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Custom cell fracture pieces
I heard about the cell fracture feature, and it is quite interesting. however i want to know if i can set custom objects as pieces. for example, i could replace the default piece shape with lego blocks, or cubes, or something

No, that’s just not how cell fracture works. It cuts the mesh into cells along planes. If you want to make a mesh out of custom pieces though, I recommend you look into Geometry Nodes solutions with instancing the pieces on points distributed in a volume (such as shown in this YouTube tutorial), but the result will probably be only simple 1x1 bricks or randomly chosen pieces, not correct special bricks and such. For more precise LEGO models, you can find or build them on Mecabricks and then use their Blender add-on to import the LEGO models as separate bricks.


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Collision with Inflated Bubbles: Error in Folds
I'm new to Blender and I wanted to ask if you have any tips to avoid the issue of collision with the folds of rubber balls. When I see it, strange pixels form and the fold isn't smooth. What do you think could be causing it?

Any information for me would be extremely useful for the study I'm doing. Thank you

Have you considered a fake collision object, slightly larger than the hero phone, in the right dimensions to be convincing to the camera.. to soak up the (expectable) error in collision  approximation?

You're thinking that the error depends on how the iPhone model is made. I replace it with a same shape. Thanks

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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How to extract this self-luminous transparent channel?
I tried shadow capture, but it turned out that the shadows were black, and the self-luminous couldn't be caught, and this problem had been bothering me for a long time

Just setting your collection to Indirect only should do the trick.

Thank you my brother.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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How to control the random rotation angle of star glow in blender synthesis

This star glow looks too uniform, I wonder if there is any way to make them random, like random size, random angle, random transparency, which is confusing to me because I can't find a node that can control this

The objects are all the same in shape, size and brightness - why should there be random glow? In reality, the size and strength of a glow depends on size and strength of the light emitting object and on technical properties of the lens, sensor etc. taking the picture. Also the angle of star streaks are dependent on the techincal properties of the device capturing it. For example star streaks in Hubble telescope pictures are different from JWST pictures - but the angles are always the same for the same telescope. Variation in size and strength comes from brightness and size of the star.

@GordonBrinkmann: he wants it random...and he didn't write anything about realism ;) it is right what you are writing ...but in German school class we would say: Thema verfehlt ;)

@Chris Not really: as I said, in reality randomness is created by variation in the source objects and by variations in technical devices. This can be transferred to the Glare node as well (not for streak angles, but glow size and strength) - if he wants variation, he can get that by varying the size and brightness of the "stars". I did not ask, why don't you want how it is in reality, I opened with: they are all the same, why should the glow be random? At least (since there is no "randomness" setting as he already discovered) there is no source providing variation for the glow.

...and it would have been nice if the uploaded file would at least show the same result as the screenshot, but the glow there is completely different.


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How to Make a Texture for a Singular Mesh with Multiple Textures
Alright, so I'm still very new to Blender and only just started getting into 3D modeling. I am making a mesh for a game I'm working on, and need all of my mesh parts (excluding the plane) to be in one mesh. I know I can do this via Ctrl+J, but I have no idea how to do the second part; making all the textures into one texture and mapping them to the right spot. I'm pretty sure I have to use Smart UV Unwrapping and then Bake textures, but I get lost from there.
Is anyone able to help me out? Please let me know, thanks!

Heelo and welcome. Please make a search first before asking, possibly redundant with all these questions: https://blender.stackexchange.com/search?q=one+uv
Tutorial : https://blender.stackexchange.com/questions/15510/possible-to-bake-texture-to-new-uv-map


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Relationship between rigid body constraint stability and rigid body weight
I am simulating a rope in Blender, represented by a chain of rigid bodies.
Each rigid body is linked to its neighbor using a generic constraint that locks X, Y, and Z linear movements. The topmost rigid body is set to passive, while all others are active.
Importantly, the bottom rigid body is heavier to exert additional force on the rope (F=m*g).
However, I am encountering stability issues when using smaller masses for the rigid bodies above the bottom one, where gaps appear between them. Increasing their mass stabilizes the simulation and prevents the emergence of gaps.
I know I can improve stability by increasing the substeps per frame and solver iterations, but I am interested in understanding the underlying principles here. Is the maximum holding force of a constraint dependent on the masses of the connected rigid bodies, especially under the tension applied by forces?
Thanks for any help!

10kg bottom, remaining rigids 0.001kg

10kg bottom, remaining rigids 1kg

in your case the constraints are just limited by the accuracy of the solver. Extremely high and low masses lower the accuracy especially when multiple constraints act together. You can try to counter it by increasing the steps per frame but it is not ideal to have such extremely different masses act together.
Also the generic constraint type is less accurate than the others. You have effectively created a point constraint with the generic constraint. Even at the same substep and iteration values the generic type will be less accurate than the point constraint. You should just use the point constraint and get the free accuracy benefit.

i used the GENERIC constraint to additionally lock the z rotation. i needed this to approximate the friction on contact with other rigid bodies. i'll test again with the POINT constraint and compare the stability and performance. do you have any other ideas on how to apply a tensile force to the lower end of the chain/rope?


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How to set origin to geometry center
I selected a model and use "Origin to Geometry" to set origin. As a result, the yellow point move to the head part of model, instead of the model's center.
So it's clear that blender default the geometry center based on the volume of the mesh. On my case, there are more meshes on the head of model.

Image reference:
How to recenter an object's origin?
If I use "Origin to Center of Mass (volumn)", the yellow point will be on the center of course.
But if my project requires that I must use "Origin to Geometry", how can I let the point on the center of model?

It sounds like you’re saying you need Origin to Geometry to do what Origin to Center of Mass does. Why on earth can’t you just use Origin to Center of Mass?

my project requires that I must use "Origin to Geometry"

So, what is the definition of "Origin to Geometry"?

Try to use different center method to set origin.


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How should I build a realistic water slide?
I've seen a few posts online about this question before, though all the answers lack realism to the slides. My main issue is not knowing where to begin. I've tried several methods though all of them seem to have some kind of problem.
(I should note that I don't know everything about Blender yet.)
Example of what I'm looking for:

There are a few things to note:

Each segment of the slide has 2 connectors on each side split down the middle. The rotation of these connectors varies per piece.
I would preferably like to have each slide segment split as a separate mesh for exporting.
Some slides have non enclosed sections with varying heights depending on forces (see image below.)

Sorry if it seems like I'm asking for too much here. I just need to be pointed in the right direction on how to do something like this. As I said earlier, the other posts about this are great, but they lack the realism I'm trying to achieve.
Thanks for reading!

I think you should start by making just the tube shape, and then extruding various bits of it to make the seal.

@TheLabCat ideally I would like to use a Curve with the tube shape. However when I try to split the curve to rotate a segment, it creates gaps. https://gyazo.com/ab8b4740fd0afb797cb27514cc9ec755

*after converting it to mesh.

@TheLabCat I get what you mean. But I was hoping there would be an easier way rather than selecting the desired edges of each segment. That seems really tedious.

There probably is with geometry notes, but those came after my knowledge had pretty much solidified IMO. It might be tedious, but it might not be too bad if you use tools like select edge loops.

If you build it in 3.2 alpha you will have some geometry nodes to choose from that were not there before.  The trim curve and extrude node are super useful for a project like this.  An advantage to building it with geometry nodes is that you can copy your "waterslide modifier" to as many curves as you like.  However, this may take some patience to put together, and you will have to change the design to fit your exact needs.  Remember that the previous suggestions on Stack Exchange you have read for building waterslides were solid advice, and the realism will come from focussing on each element of your scene and working on the details until you are satisfied.
Here is my idea-
With Add Curve: extra objects enabled in your preferences create an interesting curve, such as a spiral with a bit of height.

Then add a geometry nodes modifier and begin to work on your tree.  Also add a solidify modifier after it.

Here are the necessary nodes to create a tube out of your curve with the trim curve node so that we can adjust the length. Use an arc as the profile, in order to create the non-enclosed space on the slide:

Then build the outside lattice or edge rings from the same curve:

After you have connected everything here is what you should have:

If you copy the tree and change the profile curve to a circle instead of an arc, you can have the enclosed part of your waterslide.

optional If you wish to eliminate the solidify modifier or smooth the rivets, it can be done without them:

After change the trim curve, delete or add some nodes, and this should at least give you enough ideas to start working.

This looks really helpful! Thank you so much!


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Make falling cylinder rotate as it falls
I have a cylinder object falling and hitting pins as a game element, I want to make it rotate on the 'Y' axis as it does so in order to look more realistic. Tried keyframes but it must not work on an object with Rigid Body? Any ideas?

You could have 2 cylinders of the same size, put them at the same location, give the Rigid Body to one of the 2 cylinders, make it invisible, don't give any physics to the other one but parent it to the first one and keep it visible. Give it a rotation animation on Y, it will follow the first one and it will rotate on itself.

Awesome thanks, this works also!

If the cylinder sometimes falls to one side and sometimes to the other it would look quite unrealistic if the Y rotation always keeps spinning in the same direction. And if you would change the animation manually according to the way of the rigid body, you can just as well animate it all like that and completely abandon the animation.

@Gordon Brinkmann You can change the direction at some moments, but I'm not sure what you mean with your second phrase, maybe propose an answer, I've tried to mix animation and rigid body with the Animated option on and off but I couldn't make it work correctly...

@moonboots What I mean is, if a real cylinder would fall through these obstacles, it would not just spin all the time, the spin would be dependent on how it hits one obstacle after another. Simply animating a rotation by keyframe would be far from realistic. Chris' answer is okay so far - I just don't understand why the OP's doesn't seem to rotate at all, at least rigid bodies have some friction by default...

sure I think that Chris' answer is probably the best, but if for some reason the OP chooses to keyframe the cylinder he can still create as many keyframes as he wants and change the Y direction at some point, etc

This works "alone" by physics, if you give both, the cylinder and the obstacle, just more friction:

result:

i "cheated" here just a bit by locking some location and rotations so the cylinder doesn't fall out.

Of course you could also solve this by adding a second "transparent" plane with rigid body passive in front.
Blend file to check it out:

Thanks a lot, was wondering if it was possible with just rigid body, will play around with settings!

@Diarmuid If you want to give it some more rotation as if it started falling while already spinning, go to frame #4 and hover your mouse over the (disabled) Animated checkbox in the Rigid Body settings. Hit "i" to insert a keyframe. Then go to frame #3 and set a keyframe for the rotation of the object. Now go to either frame #1 or #2, check the Animated option and press "i" on it again. Select the object and rotate it slightly and insert another rotation keyframe for it. Depending on the frame and how much you rotated it it will have more or less initial spin.

@Chris Your solution is the way to go, it doesn't make sense like in the other answer to animate the rotation of a second cylinder independently from the falling rigid body.

Depends what you want to have …if the OP is happy with it - I am happy with it too…♂ and with 4 upvotes I even got more reps than the correct answer check

@Chris As I just commented on moonboots: what I don't understand why the OPs setup doesn't rotate at all... the default rigid bodies already have some friction. The animation in the question looks like a particle falling, not a rigid body.


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Removing floor and make objects fall animation
I have coins falling into a cube. After a few seconds of them landing I want the 'floor' to move and coins to then fall through down. I have the floor plane set to animate out of the way but the coins just stay where they landed and do not fall down then.
I have tested deleting the floor completely just to see if there was some issue but they fall all the way though then so it must be something to do with the coins after they have initially settled on the plane? Settings below are what I have on the coins.
Any ideas? Thanks

Look at Rigidbody World settings and make sure the frame range extends to the duration you need.

normally you should apply all rotation and scales...

for the object called Plane, in your file its Animated option was not activated

moonboots is right, if you check the animated checkbox of both animated objects and keyframe then on the last animated frame and uncheck and keyframe it one frame later, it works [1]: https://i.sstatic.net/wghaB.gif

moonboots, Bingo! Thanks so much

Just activate the Animated option of your floor, otherwise its movement won't be taken into account, only its initial location, and the coins won't fall.


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Overlapping material mapping on plants comes out black - possible z fighting
I have downloaded some plants from GlobePlants,but when I apply the materials and alpha to the flowers, some of the densely packed areas come out black. Could someone tell me what is happening and how I can fix this?
I have tried different alphas, changing the light passes, the camera min. and max, as well as importing from rhino instead.

https://blender.stackexchange.com/questions/27718/black-artifacts-when-looking-through-many-transparent-objects https://blender.stackexchange.com/questions/42023/transparent-textured-planes-produce-black-artifacts https://blender.stackexchange.com/questions/18857/how-to-eliminate-cycles-artifacts-with-many-overlapping-volumes


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Baking a Normal Map with details
It's not the first time that when I have to bake a normal map I lose a lot of detail. In the previous model, in the low poly mesh I had around 30k faces, in fact I could see the details.
Now in this new model I wanted to reduce the low poly faces for better optimization.
The problem is that I can't get enough detail from the high poly mesh. What can I do?
Another thing is that i retopologized the mesh with Instant meshes so it isn't perfect. I attach an image with uv grid so you can see the seams.
In case you want to try to view the problem you can download the file here:
https://www.swisstransfer.com/d/db3f1890-0752-4148-b833-fa38f84c4a7b

Why are you using max ray distance?

it seems to work fine, I've applied the scale of the high-poly, I've created a new image (32-Bit Float) and baked without cage and with an Extrusion value of 0.01, here is the result:

thank you so much!


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Can you export shapekeys without the mesh in GLB?
I am exporting shapekeys and animation data from Blender to GLB format. However, the shapekeys are dependent on the mesh, causing the GLB file size to become too large.
Is there a way to export only the shapekeys in the GLB format without the mesh?

That is like trying to sell toast but without the bread. I doubt that is possible


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Compositing get's applied in viewport and render result window but not in the saved image file
I am currently playing around with eevee next in Blender 4.2 just added a bloom effect via this simple compositing setup (the result doesn't change whether the alpha sockets are connected or not):
in the viewport it looks like this:

and in the render result it looks like this:
But after saving the image as a png with 16 bit color depths and (in this particular case) 50% compression (I tried all kinds of values) it looks like no compositing was applied at all:
I already tried to add a file output node after the glare node but it produces the same result.
In the post-processing timeline, both compositing and sequencer are checked.
Results do not change when toggling Raytracing.
While writing this I came across this post (don't know if this is still relevant): Glare alpha not saved to png file
and tried this node setup which produces the same result as before:

I am pretty much out of ideas of what to try at this point, so any help is appreciated.

It’s PNG. PNG cannot encode alpha properly. Export to EXR instead. It will work.

https://blender.stackexchange.com/questions/222837/blender-does-not-set-the-alpha-channel-correctly https://blender.stackexchange.com/questions/272917/transparent-emissive-objects-glow-effect-not-visible-in-rendered-output-files/272919#272919 https://blender.stackexchange.com/questions/164895/rendering-with-a-luminous-outline-on-transparent-background/165275#165275


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Easy render of CLT (Cross Laminated Timber)?
I'm interested in learning how to create a material that would do a "decent" representation of Cross Laminated Timber. Typically, these are mostly rectangular shapes with simple cutouts and other features used in constructing floors, walls, and roofs of Mass Timber type buildings. I'm not necessarily interested in photorealistic, but something that would reasonably represent grain direction on the top of the panels and the cross laminations visible on the end grain. Any ideas?

Some variation on this ? Do you want to model the slabs as single cuboids, or make them up of planks?

I'm more interested to model as cuboids. Example above is 4" thick, so I'd model a panel that would be 4" thick. Just not sure oh how to material the edges and top/bottom.


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Blender Python Translate object using three points
I have a collection of objects that I cycle through with a python script. Each object has six custom properties: OriginX, OriginY, OriginZ, TranslateX, TranslateY, and TranslateZ.
Each property represents a coordinate in X, Y or Z. The first three are 3D points that the object is imported to. The last three are the points I want to translate the object to.

In the image OriginX is #1, OriginY is #2, and OriginZ is #3. I want to translate #1 to #4 (TranslateX), #2 to #5 (TranslateY) and #3 to #6 (TranslateZ).
In my code I effectively transform (via rotation) the part from point #1 to point #4, but how can I apply a translation with #2 to #5 and #3 to #6? The object do not scale.
In NX I would create a coordinate system (Csys) for each set of three points (Origin and Translate) and do a Csys to Csys transformation. I cannot figure out how to accomplish this in Blender Python.
Any help would be greatly appreciated.

Hello ! As a technical standpoint this action is not a pure translation but a transformation (translation + rotation + scale). This is usually done with a Matrix multiplication. If you know the scale is uniform in all axes, you can also decompose it with a translation from 1 to 4 (which is trivial) a rotation from 1-2 to 4-5 (compute the rotational difference and apply it) and a scale from 1-2 to 4-5. If the scale is not uniform you'll have to scale each axis separately but then you'll miss a component in the Y axis. (Unless it stays the same) then you can set it to 1


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Is there a tool to erase out or reduce delta from a shape key? Like Morph brush in zbrush or Erase brush in Mudbox?
When you are using many shape keys for your sculpting, you can decrease the value of a shape key to reduce your sculpt amount. But it will apply same value reduction on all the sculpt in the shape key.
I want to tastefully erase only some of the sculpt in the shape key.
Is there a way to do this interactively?
In zbrush, your can store a morph target, and use morph brush so that your sculpt can go back to the stored sculpt and your pen pressure will determine how much you can go back to it so you can choose which sculpt to keep and how much.
In mudbox, there is a erase brush you can use it on a sculpt layer, and again your stroke and pressure will determine how much sculpt in that layer to be erased or reduced.
I do not see anything like that in blender....
If you are doing very sensitive and artistic sculpting, it is very nice to mix multiple layers of sculpt just the right amount.....
I am surprised that there is no equivalent tool for blender that all the other major 3D sculpting sofewares have....

Yeah, you can do that.  It involves different tools.  To me, it doesn't sound any more complicated than your description of Z's tools, but it will probably take getting comfortable with other elements of Blender before it feels that way to you.
What you do is create a vertex group to modulate your shapekey.  If you're already comfortable with weight painting, that's easy enough.  If you're not-- well, it does take people some time to get comfortable with weight painting.

Below the shapekey value, there is a field to enter a vertex group to modulate the shapekey-- I'm hovering my mouse over that field so you can see the tooltip.  That will blend the shapekey according to any weights we've painted for that vertex group, as demonstrated by comparing the shapekey on the left (unmodulated) with the shapekey on the right (modulated by the vertex group shown.)  It's the same shapekey.
If we'd like to write this to a brand new shapekey, that builds that vertex group modulation in, we can use the shapekey specials and do a new shape from mix.  That will respect any VGs set for any shapes we've got mixed in.
Another useful tool is blend shape from mix, in edit mode, which will add or replace the shapekey vectors of any selected vertices with any other shapekey, but that's not "soft" across the mesh, not the way that vertex groups are.  (You can still blend at 0.1 or 2.0 or whatever, so it's soft in that respect.)
Weight painting isn't hard, and is useful for a lot of modelling tasks, although people generally first encounter it when working on animation tasks like armature deformation.  For this vertex group, I just alt click dragged across the mesh to make a linear gradient.  Although I'm not certain those hotkeys are the same as yours.  Most of my weight painting involves either linear or radial gradients on Add or Multiply mode.  Making a quick VG like this is pretty easy when you've done it a few times.


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Weird colors in normal map baking
This drives me crazy! I tried many times, always wrong. Please help me with this.
It is the default cube in the default scene. I duplicated one, added a subdivision surface modifier and added some ring cuts. Applied the modifier.
In the bake set-up, it is like this:

When I bake, I get this:

The Blender file is here

Unplug the Image Texture for the moment as the high poly also uses it, and give a bit of extrusion to the bake as the faces of the 2 cubes are overlapping, and it will work:

It works! Thanks a lot!


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Object pivot point stuck to origin and duplicated objects move in tandem
New to blender, please bear with me.
Created a face from multiple objects, then joined them with ctrl + j. Things went wrong, wanted to edit the individual objects again, so unjoined by separating by loose parts.
Duplicated this new collection.
For both collections, the pivot point seems to be locked to the world origin (see image). Shift + S setting cursor to origin then Shift + S again Selection to Cursor does nothing. Tried alt + p to clear parent, that didn't seem to do anything either.
Additionally, when I drag any individual object within each collection, each entire collection moves proportionally to one another.
I've also tried changing the pivot point to median, as suggested here (why aren't move parameters staying with object), but that didn't work.
I suspect I've bungled something royally along the way, but can't seem to figure it out.

Solved. Selected the object then in upper left tab option "Object" selected Set Origin -> Origin to Geometry
Still unclear how I got to that point however, but posting in case anyone else has this issue.


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How to scale object so that two specific points have certain distance
complete newbie to Blender. I am editing some files for 3D print for personal use and was able to do most of what I need with help of this forum and YouTube tutorials, but need help with final step. I need to scale the object, but not sure how. I know that I can transform the whole object based on X, Y and Z axis.
I need to set the distance between middle of the eyes to a specific value in mm and scale the whole model based on that. Is it possible to do something like that? If so, could you advise how? Any help would be appreciated.

In this example, I want Suzanne scaled to 0.5m between the centers of her eyes.
The Measure tool and type-in values can help with this. (Ensure the Scale of your object is  CtrlAapplied.) In Edit Mode:

Snap the measure tool to the reference geometry
A select all
S to scale, and left-click
In the Scale operator's  F9 'Adjust' panel,  LMB swipe all fields to make simultaneous entries, and type in: Desired Length / Measured Length

(Using Blender 3.6.8)
Approach
Use two cubes as guide, combined with Snap to Vertex activated.
Setup
Using the middle top icons of the 3D Viewport:

Set Transform Pivot Point to Individual Origins.
Set Snap to to Vertex, and set Affect to Move and Scale.

Step 1

1. Set the cursor location to a first reference position (e.g. the centre of Suzanne right eye).
2. Displace the object to scale origin to the cursor location (menu Object/Set Origin/Origin to 3D Cursor).
3. Add a cube (menu Add/Mesh/Cube).
4. Scale it such that one of its dimensions (e.g. X) matches the specific sought value (menu Object/Transform/Scale).
5. Apply the cube transformations (menu Object/Apply/Scale).
6. Set the cursor location to one corner of the cube.
7. Displace the cube origin to the cursor location.
8. Select the object to scale and move the cursor to its origin (Shift S 2 Cursor to Selected).
9. Select the cube and move its origin to the cursor location (Shift S 8 Selection to Cursor).
At this stage, the object to scale and the cube are sharing the same origin, and one side of the cube matches the sought length.
Step 2

1. Select the cube and duplicate it without displacement (menu Object/Duplicate Objects).
2. Set the cursor location to the corner opposite to the origin of the copied cube.
3. Scale the copied cube moving the mouse such that the cursor snaps to the second reference position (e.g. the centre of Suzanne left eye).
4. Apply the copied cube transformations.
At this stage, one side of the copied cube matches the original length of the object to scale.
Step 3

1. Add a Copy Scale constraint to the object to scale.
2. Choose the copied cube as Target.
3. Select the copied cube.
4. Set the cursor location to the corner opposite to the origin of the copied cube.
5. Scale the copied cube moving the mouse such that the cursor snaps to the right corner of the original cube.
6. Select the object to scale and Apply the constraint to freeze the scale.
Resources:


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Change starting pose of animation
I have model with a T-pose as rest position. I have an animation that I created by deleting the the first 1/2 of the key frames in the animation to get just want I needed. However, but cropping the animation, the rest pose of the armature in that animation is now much closer to an 'arms at their side' pose. When i retarget this animation onto the T-pose model the arms are now at close to 90 degrees away from where I need them.
I'm quite new to Blender so I need help working out what I need to do so that when I retarget the animation onto the T-pose model, the arms remain at its side where I need them.
Thanks very much?

i highly recommend providing your blend file so we see what you done, show us what animation you want by e.g. providing a yt link


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Handle save unsaved changes user choice
I need to handle result of standard "Save unsaved changes" dialog (I want to send some signalr messages on "Yes" and on "Cancel" dialog results).
How can i do it in python script?
I mean this message.

Hello. I think you can use atexit to run custom code just before Blender closes. I don't know if you can reliably catch where the user clicked though. https://docs.python.org/3/library/atexit.html


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Bake color ramp
i have a model in blender that i want to export, but when i do it it doesn't have textures. The fix for this is to bake my color ramps to an image, but when i do it, the image that is created is just a flat color, and not an image with some different colors.

You could do a render, then keep the camera view, do a U (Unwrap) > Project from View in Edit mode, and project the render onto the surface, except you'll still have to paint the other parts (back of the object)

Can you explain it a bit more im kinda new to blender!


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Object as cut mask
a few days ago I started to learn Blender. I only have experience with Affinity Designer and Illustrator Layers and Masks and stuff like that. I have this little scene:

Link to the file: Blender File
What I want is for the red frame object to also be a sort of cut mask for the green object. So, in the rendering view, I want to see only the parts of the green object that show through inside the opening of the red frame. I hope I have described it in an understandable way.
What is the name of the technique or tool in Blender to do this?
Sorry if this question has been asked before.

It is possible, but might be hard for a blender beginner.
So i found a solution with geometry nodes and a "helper" object.
So you need to create a helper object which is just a copy of your red object, but you have to extend its edges to "infinity" ...or just make it big enough.
So mine looked like this:

then parent your red object to that new object, so whenever you move your red object, the helper object will be moved with it.
If you now turn on "viewport display" -> wire, you can see through that helper object and you can see what happens.

Now add an empty as "next" helper object which represents our point of view.
You could e.g. parent that to your camera so you will always have your effect whenever you look through your camera.
Now add to your green object a geometry modifier with these nodes:

What does this do?
It "shoots" rays from the empty to your green object. And whenever it hits something else (e.g. the helper object), the geometry of the green object (just a vertex) will be deleted. It is important that you give the green object lots of subdivisions. The more, the better the result.
Result:

Thank you for that. I have tried to reproduce it. But the green object is always hidden now. See Frame_v1.blend

wow...you made everything right...except this here :"it is important that you give the green object lots of subdivisions" -> so select your green cube, tab to edit mode and then right click -> subdivide -> enter 20 and you will see the result. And thank you very much for providing blend file, so i could check it out !!

I got it to work now. But I think my use case is a bit simpler, so maybe I don't need this elaborate solution: 1.) the reference point ("Next") is always in the center (X/Y) of the red object and Z is infinity. 2.) the green object is very flat and is just below the top of the red object. Again, your solution works quite well (see: Frame_v3.blend. There I replaced the green cube with a plane ("Canvas"), which I can now move (X/Y) and see the part of the photo I want to see :-) However, I will also try the solution from moonboots below.

If you plan to have a transparent background for your film, create these additional faces around your pink frame and give them this material which is a (Shader >) Holdout plugged into the Output:

Thanks for this. For my simple use case, see Frame_v4.blend this is probably the best solution.

ok great then..... ;)


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Knife tool won't go away
I'm pretty new to blender but I've nearly got the hang of it. Unfortunately, I keep running into the same problem: whenever I use the knife tool, it won't go away! No shortcuts are working and I can't click on any other tool - it just makes a new line in the workspace below the sidebar. I used to be able to quit blender and reopen it, but now that I'm working on one project, every time I reopen the project, the knife tool is already in action and I can't do anything.
Is this a glitch or am I just missing something really obvious? Any help appreciated:)

This is one of those obvious dumb ones, but did you try pressing Esc?

@ChristopherBennett Oh my god. I feel like such an idiot!!! Thank you so much!!! I hope you have a lovely rest of your day:)


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How do I mould a specific portion of a head model to match the shape of the one beneath it?

This is my first time using Blender, for the purpose of fixing an edited head model in the video game Fallen Order. My goal is very simple, I just want to alter the edited head model on top, so that the back of the neck matches the one highlighted in orange beneath it. However, my every attempt to either manipulate the vertices directly, use sculpt tools, or use the shrinkwrap function just results in a deformed mesh that has bumps or tears or weird distortions, and I'm really clueless as to what to do. I just want to edit the neck so it no longer clips with the clothing of the character it belongs to, but its so outside my capabilites I really need help.
Thank you!

There is no magic bullet to this kind of thing. Modifying existing models takes time and skill. But here are some tips.
To mimic some other model's shape, you can set the source model to wireframe mode and then select your new model. Enter edit mode, activate Proportional Editing and push and pull your shape based on source mesh shape. This usually works best for rough shape changes like changing proportions, matching pose of another model, or modify side or front profile of your model etc.

To drop specific vertices on the surface of your source model, you can enable face snapping, then select some vertices in your new mesh, and move a vert. This makes the vertex snap to the target surface. This is precision work, don't expect to select a big clump of vertices and then expect something good to happen if you move them. Start slowly and see how snapping works.

Sculpting tools too can be very useful. Do changes is small steps. Grab and Elastic deform brushes are my favourites. Here you can also use the wireframe trick, simply set your source model viewport display mode to wireframe, and the shape your new mesh in Solid shading mode.

Thank you for the tips, I really appreciate it! I'm finding it incredibly difficult to edit via vertices as there are thousands on this mesh, and as the shape of the neck is wafer thin, the tiniest movement causes a deformation. Do you have any advice for the sculpt tools? I found myself accidentally tearing holes in the mesh using grab, and it was very hard to retain a smooth mesh shape as required on a neck.
I will give snapping a go too, I'm not after a perfect result, just one that will reshape it so I have no neck clipping ingame.

Proportional editing (also called soft selection in some software) helps with issue of too many vertices to move, you drag one or more, and nearby vertices will follow. You can also adjust the falloff size for this effect with your mouse wheel. Without seeing the model it is hard to say what is causing holes, maybe your mesh surface has seams? Sculpting tools are usually the best option for medium and high resolution organic mesh shaping (in any 3d software). Grab brush for example has very soft effect,  and you can smooth the result afterwards by shift + left clicking mesh.


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Blender 3.0 Laser Scan Effect (With Shadows)
im so excited, this is my first Stack Exchange question :)
everyday i discover more of the blender community and this is yet another great way to learn :)
thanks for reading through this.
my aim is to create a "Laser Ray" object that looks like these types of lasers in EEVEE for a video im making. it is very important to have the shadow portion of the laser for the effect im trying to achieve
images for reference:

I found an answer to something very similar posted here in 2020,
i attempted to run the scripts posted there but unfortunately i did not get anything from them, if there are any python wizards here your help would be much appreciated.
thanks again for your help!

Hi. Please specify which of the script you tried running. It would also great to see the error console output.

thank you for replying Hezi, the scripts i am trying to run can be found here: https://blender.stackexchange.com/a/194328/141861
I don't know how to link them or post them properly as a comment, help with that would be appreciated as well. Thank you!


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need help to merge two halves of a 3d object
I have two halves of an object i scanned with a 3d scanner and have imported the .obj files with texture.  I need to merge the two halves together to make one smooth object and remove the overlapping mesh.  Forgive me if this is a simple solution but i am not able to find a good tutorial on this after searching for days.

It looks like a regular sphere: can't you create a new sphere and apply the material to it?

these are two halfs of a 3d scan.  how can i save the material off each half and combine it into one material to use?

You can UV map both parts, bake the material, combine the two in photo editing software. But that's for another question (which I'm sure is here somewhere!).


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Objects don't show up in render, render button greyed out
I'm pretty much a newbie with Blender, but have set up a few scenes before. Now I have been working on a scene and my renders with cycles turned out ok so far. But then I must have pressed some button and don't know which one, so that about the half of my objects don't show up in the render anymore, although they show up in the viewport and are selected for render. Their render symbol is greyed out, as shown in the picture. What did I do? I'm using Blender 4.0.2 on an Intel Mac.

Thanks!

Turns out I have accidentally disabled the whole collection. Problem solved.


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Blender 4 - in Orthographic projection view shows all invisible lines - how to return as it was in version 3?
In previews Blender version the perspective and ortho views in edit mode was the same.
Now the perspective mode is as usual, but ortho view displays all visible and invisible lines - this is very inconvenient and confusing. I'm looking for a way to disable it.
The sample of all this lines:

You'll be glad to know this is not the expected behaviour, due to a version-change. It is most probably due to an insufficient / misplaced viewport Cilipping Range .. (N panel, 'View' tab, Clip Start / End).. If that doesn't turn out to be the cause, share a version of the file showing the problem on https://blend-exchange.com/


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How to wrap one object around another?

I've been trying a couple of different ways to get an object that has depth to wrap around a boot as a sort of strap. I've tried shrink wrapping a plane then adding depth, tried to shrink wrap normally, tried to parent it to a plane and deform to the plane while shrink wrapping the plane, and now trying to conform. I'm not sure how to achieve what I want to do.

Create a curve that turns around the calf:

Create a plane, give it the following modifiers: Array (Fill Type > Fit Curve), Curve, Shrinkwrap, Solidify:

Apply the modifiers and move the edges so that the faces don't overlap:

Thank you so much, that is so helpful. The step by step guide is really appreciated!


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Export model color attribute to png

I can't seem to find a answer to export my mesh materials to png

Look into texture baking.


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Failed to solve motion; most likely there are no good keyframes error
I'm getting this error that doesn't let me continue with the cleaning process, i've already searched and everyone says about having less than 8 points, but i'm just starting the cleaning process i have more than even 50 points, so why is this happening?
The weird thing about it is that the first time i press Solve Camera Motion it works correctly, but if i press again with the same changes or i try to clean up and press Solve the error message appears, so it looks like just blender messing with me with random errors with no logic. Has anybody encountered this problem?
This is my tracking with tons of markers (that seems to be less than 8 for Blender)


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High Poly -> Low Poly Texture Bake Problem (UV seems to be ignored entirely)
I've been following this awesome tutorial (https://www.youtube.com/watch?v=-dc4KN2bdrw&ab_channel=BlenderBones) on converting photo scanned objects to usable, low poly objects. I've been able to follow everything up to the part of baking the diffuse textures from the high poly object to the low poly object (Link to time stamp on video: https://youtu.be/-dc4KN2bdrw?t=361). It's not working like his. It's doing this and have no idea what it could be doing.

I remapped the UV's of my lower poly object to make more sense and note there is dramatic difference between the high and low poly model UV's, but every attempt at trying to maintain the high res textures onto this low res model has not been working correctly giving very strange outputs for textures and looks like it completely ignores the UV mapping of my low poly object.
I've toyed around a lot with the render settings but still don't get adequate results. I've attached a link to google drive with more pictures. Would appreciate any knowledge and help.
(MORE IMAGES) >> https://drive.google.com/drive/folders/14LWVC06HjRELwkHG6kgQVPMJlMSkMsnj?usp=sharing

You don't have any pictures of your UV map.  That's the first thing I would look at.  The second thing I would look at would be if you have multiple UV maps.  A link to a file would let people look at that, as well as any other details, more easily.

@Nathan - Thanks for your response. I just uploaded the project file and some pictures of the UV maps of the high res tree and the low res tree to the google drive folder. Would you check that out?
Just as a note, one of the UV's was out of place because i was moving it around to test if I could bake the texture from the high res to a duplicate high res model. It worked! However when I tried scaling one of the islands in the UV it seemed to have a lot more trouble matching the texture to that UV.
https://drive.google.com/drive/folders/14LWVC06HjRELwkHG6kgQVPMJlMSkMsnj?usp=sharing

Thanks, Nathan. You're right about the dirty UVs being show stopper. Nothing would've worked without cleaning my UVs up and it makes sense to me why it would be one big blob now. After cleaning I got these results:

So it still wasn't quite working but I continued to play with some of the render settings and I simply changed my "Max Ray Distance" to 0 and it came out just right!

I'm not even sure the science behind the ray distance, but changing it to 0 worked like a charm.

Your object does not have a good UV map:

We can see that there is at least one face that occupies the entire 0,1 UV space.  Other faces overlap with this face.
To get a reasonable bake, you cannot have any overlap in your UVs in the 0,1 space.
There may be other problems as well, but this is a show-stopper that needs to be fixed before any texture bake has any possibility of doing what you want.
We can also see, in the 3D viewport, that there are a lot of loose vertices that you should probably clean up.
BTW, why disable overlays in UV?  This will confuse people who inspect your file, and the only reason to use the UV editor is to edit UVs, which cannot be done when overlays are disabled.  If you want to just look at your image in 2D, use an image editor viewport.


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DXF import to Blender with big Coordinates
New to Blender.
I want to import an DXF with big coordinates into Blender, move the Objects to 0 so i can work on them but dont change the orginial Coordinates of the Objects for the Export.

Blender doesn't handle very high coordinates well. Can't you add your delta from where the dxf came from and remove it after exporting it ?

What do you mean by adding my delta?  DXF came from AutoCad  btw

I mean center your object in autocad around 0, 0, 0 and then import it in blender. Then export it as is from blender, and use the opposite of the vector you used to recenter your object in autocad

I dont want to mess with the objects orignial coordinates as i cant have any errors here.
I thought about something like a temporary second Coordinate system that is assinged to the Objects while in Blender

What about placing an Empty at 0, 0, 0 and parent it to an object that's off center. Then move the object to 0, 0, 0 which moves the Empty somewhere else. After you finished working on the object you unparent the Empty and instead parent the object to it and move the Empty back to 0, 0, 0. Of course that's tedious. Using Delta Transforms might be easier. Do you want to move a complete collection of DXF objects to the center so that they keep their relative locations to each other or do you want to move each single object to the center on its own?


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Collision Detection
So i found a script for an Collision Detection @ https://www.cbcity.de/simple-3d-collision-detection-with-python-scripting-in-blender
But it seems outdated as i get some Errors , any ideas on how to make this run again?

so if i want to check the collision between two pointclouds is there an easy way to assign multiple objects with bounding boxes?

The script does just work for 2 cubes. I don’t think that there is an easy way - but there might be built-in functions which can do that. I know there is such a functionality in UPBGE - so you can easily detect collisions between objects - but I don’t whether vanilla Blender has this too.

Check this out:
import bpy
from mathutils import Vector

def get_BoundBox(object_name):
    """
    returns the corners of the bounding box of an object in world coordinates
    #  ________
    # |\       |\
    # |_\______|_\
    # \ |      \ |
    #  \|_______\|
    #
    """

    ob = bpy.context.scene.objects[object_name]
    bbox_corners = [ob.matrix_world @ Vector(corner) for corner in ob.bound_box]

    return bbox_corners

def check_Collision(box1, box2):
    """
    Check Collision of 2 Bounding Boxes
    box1 & box2 muss Liste mit Vector sein,
    welche die Eckpunkte der Bounding Box
    enthält
    #  ________
    # |\       |\
    # |_\______|_\
    # \ |      \ |
    #  \|_______\|
    #
    #
    """
    print('\nKollisionscheck mit:')

    x_max = max([e[0] for e in box1])
    x_min = min([e[0] for e in box1])
    y_max = max([e[1] for e in box1])
    y_min = min([e[1] for e in box1])
    z_max = max([e[2] for e in box1])
    z_min = min([e[2] for e in box1])
    print('Box1 min %.2f, %.2f, %.2f' % (x_min, y_min, z_min))
    print('Box1 max %.2f, %.2f, %.2f' % (x_max, y_max, z_max))

    x_max2 = max([e[0] for e in box2])
    x_min2 = min([e[0] for e in box2])
    y_max2 = max([e[1] for e in box2])
    y_min2 = min([e[1] for e in box2])
    z_max2 = max([e[2] for e in box2])
    z_min2 = min([e[2] for e in box2])
    print('Box2 min %.2f, %.2f, %.2f' % (x_min2, y_min2, z_min2))
    print('Box2 max %.2f, %.2f, %.2f' % (x_max2, y_max2, z_max2))

    isColliding = ((x_max >= x_min2 and x_max <= x_max2) \
                    or (x_min <= x_max2 and x_min >= x_min2)) \
                    and ((y_max >= y_min2 and y_max <= y_max2) \
                    or (y_min <= y_max2 and y_min >= y_min2)) \
                    and ((z_max >= z_min2 and z_max <= z_max2) \
                    or (z_min <= z_max2 and z_min >= z_min2))

    if isColliding:
        print('Kollision!')

    return isColliding

# MAIN
# Check Collision of Objects named 'Cube1' and 'Cube2' in Scene
collision = check_Collision(get_BoundBox('Cube1'), get_BoundBox('Cube2'))

This creates bounding boxes from objects and then returns True if the bounding boxes are touching using the BVHTree overlap method. Otherwise, it'll return False.
import bpy
from mathutils import Vector
from mathutils.bvhtree import BVHTree

def worldBoundingBox(obj):
    """returns the corners of the bounding box of an object in world coordinates"""
    return [obj.matrix_world @ Vector(corner) for corner in obj.bound_box]

def objectsOverlap(obj1, obj2):
    """returns True if the object's bounding boxes are overlapping"""
    vert1 = worldBoundingBox(obj1)
    vert2 = worldBoundingBox(obj2)
    faces = [(0, 1, 2, 3), (4, 7, 6, 5), (0, 4, 5, 1), (1, 5, 6, 2), (2, 6, 7, 3), (4, 0, 3, 7)]

    bvh1 = BVHTree.FromPolygons(vert1, faces)
    bvh2 = BVHTree.FromPolygons(vert2, faces)

    return bool(bvh1.overlap(bvh2))


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Raycast + Align Euler to Vector. Wrong Hit Normals
I try user Raycast with "Align Euler to Vector" node.
Target is simple rotate plane (4 vertex).
As a result, some triangles are rotated incorrectly. What's wrong ?

Here's how your setup is evaluated:

White line ⬅ Group Output decides to evaluate the Geometry
Cyan lines ⬅ Instance on Points decides to evaluate Points, and evaluated data returns on yellow lines ➡. Nodes (1) - (4) were evaluated.
Pink line ⬅ Instance on Points decides to evaluate Instance, and evaluated geometry returns on the green line ➡. Node (5) was evaluated.
Red lines ⬅ Instance on Points decides to evaluate Rotation for each instance, and evaluated vectors return on the blue lines ➡. Nodes (6) - (8) were evaluated.
Instance on Points finishes work, returning the data to Group Output on the black line ➡. Nodes (9) & (10) were evaluated.

I tried to make it clear Object Info and Raycast nodes are evaluated two times each. So if you duplicated those nodes, I think the execution would be exactly the same (maybe some optimizations wouldn't kick in, but other than the evaluation time, the result would be the same):

While the Object Info node might have some cache, because it returns the same data the second time, the latter, the Raycast, is given different Source Position - the 2nd time it's the position of the instance, which is already positioned on the plane.
So it is now up to the quirkiness of the floating point calculations if a ray shot from the plane down will hit the plane or not. With node wrangler enabled, CtrlShiftclicking the Instance on Points node (the context) and the Raycast node (to read values for this context) will reveal Is Hit for many instances (those with wrong rotations) is ❌ False.
The simplest fix is to edit Plane.001, duplicate the plane and move it down. Now there's a second plane with the same normal to be sampled by (7) node.
The proper fix is to use a Capture Attribute node, to remember the Hit Normal to not have to run the node again (it will therefore also reduce the evaluation time of the setup):

More reading:

Combine two position nodes from different mesh primitives inside a geometry node tree
Geometry Nodes: What Does Capture Attribute Add to Geometry?
Understanding how "vertex of corner" works in geometry node
Passing Data Into Simulation Zone


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Copy Rotation Constraint on only X and Y flips the bone when the target bone moves to much
I want to make a mechanical thing where there's a piece that would only move like a gimbal without the local z rotating but the copy rotation constraint does work it just doesn't allow full rotations of other angles and flips. Is there a solution to this or an alternative?
Here is a video:https://drive.google.com/file/d/1B01LTPHNLLg8w2IJOIQQpM30ZeKwYLGP/view?usp=sharing

Hello and welcome. While files, images, and external videos or links may be helpful additions they should not be the only way to obtain information about your issue. Don't make understanding your question rely on downloading a file, watching a video or visiting an external site. Use the builtin tools to upload images or gifs, along with thoroughly explaining the problem in written form so it can be indexed and searched for thus helping future visitors with similar issues.


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draw texturing take account of face's orientation?
When i texture an object by drawing onto a mesh (mix mode, strength = 1), i can't paint faces that are not perpendicular to the camera.

(But it works if i paint directly on the image texture)
so come questions :
How to disable this ?
The more the orientation is far from perpendicular to the camera, the lighter the color is ?
(The normals are all flipped outside)

The angle setting is in Falloff:

You can disable this by pressing Normal Falloff.
Disabling Backface culling in Options allows painting on flipped faces:

Disabling Occlude allows painting trough faces.


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My particle is rotating constantly as I move curve
I want to create this rolling velcro effect, I'm using this spiral curve as a guiding object for my velcro to roll. But the problem is that my particle is constantly rotating in a wave motion as i move the curve (but when i move the velcro to the side the particle doesn't constantly rotate).
I have tried parent the curve to a new empty but nothing works. Is there any solution for this problem?
Blender version 4.0


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Adjust circle radius by spline parameter
I am currently trying to create an array of circles of different radii in geometry nodes such that it forms a sphere.
I currently have an array of curve circles instanced on a curve line. I have attempted to set the radius of each circle by using the Length output on the Spline Parameter node but it indicates an Invalid Link error each time.
This is what I am trying to achieve:

Here is the setup:

Here is the result of the setup:

How can I effectively achieve this?

Your problem is your mixing Field-based data (Diamond shaped sockets) with static data (circular sockets). Basically blender is asking for one specific value and you're giving it values that vary depending on which part of the mesh it's referring to. I would set the first curve radius to a static value (like .1 or 1 to make multiplying easier) and then use a Scale Instances node after that with some math on your Spline Factor as the scale amount.

You cannot plug the Length of a Spline Parameter (or the Factor what you actually did according to your screenshot) into the Radius of a Curve Circle node, because it produces a single circle which can only have a single radius. This is why there is a red dashed line and an error message "Invalid Link".

What you have to do is scale the instances. Then you need to do something to match the factor going from 0 to 1 from bottom to top to something more useful for a sphere. I used a Map Range node to map the 0 to 1 range to a -1 to 1 range. Then the result x would be the sine value and to get the radius you need cos(arcsin x). This you plug into the Scale input of the Instnace on Points node.

However note that the top and bottom circles have a scale of 0 which makes them disappear. So if you want to have at least little circles there, you might want to change the Map Range node to not fully go to -1 and 1, but maybe -0.999 and 0.999:

I have 2 possible solutions for you. Solution 1 gives worse result but is closer to your original process, solution 2 gives a perfect result but the process is completely different.
Solution 1: Your problem is that the radius input only accepts a single value instead of a field. You have to scale the circles after you instance them, and at the point you can't use spline parameter.

This node tree takes the Z coordinate of an instance and uses it to scale the circles on the X and Y axis. You also control the scale through a float curve node.
And here's the result:

Solution 2: This solution adds a uv sphere and deletes edges based on the absolute value of the difference of the Z coordinate of the start and end vertex. So, if the start of the edge is at a different height than the end, that edge is deleted.

And here's the result:


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Molten Metal Blobs moving and fusing on a surface?
I am trying to re-create an advert as a practise which involves molten metal fluid blobs moving along a surface and fusing with other blobs in a natural way.
Here is the video - 3 scenes are involved : https://youtu.be/VcZetwcBZ6Q?si=7BZDPJKi1ds6BVdp
I have tried all sorts of methods involving the inbuilt Blender fluid sim, metaballs and geometry nodes and particles systems and have gone back to a geometry nodes method where I basically use blobs on a path making up one cube object but deforming with the displace modifier (to create the blob wobble). I then have a remesh modifier in the modifier stack to create the merging effect of molten metal particles as the blobs get close.
The problem comes when I animate as I have each blob on a path keyframed in geometry nodes but trying to then get each blob to move at the right speed and position relative to one another in a way which creates the effect of molten metal moving is almost impossible. It just looks like blobs moving independently.
There doesn't seem to be a workable solution to use a plug-in to animate the number and position of blobs - flip fluids won't do it, nor other plug-ins for blender. There is one called 'realflow' which I could import as alembic files but I don't know how to use that software and I am not sure if I can use the free version (the paid version is expensive)
I am just canvassing opinion on if anyone has ever done this as I think there are not any tutorials on how to do this online. If anyone can help me reach a solution I would be happy to give back and post a tutorial on how these scenes can be done.

If I were to attempt this effect, I would use a particle system with metaballs as the particle to get the merging effect. As for getting the particles to behave as you want, I would try changing the physics of the particles from Newtonian to Boids. That way you can make them move on a surface. Boid particles can be made to flock to an object, maintain a certain distance from each other, etc. With some fiddling, I am sure you can come up with settings for the desired movement.
Here is a video on the boid system you might find useful  and a video on using metaballs as particles . Good luck. I hope you found this helpful.

Thanks for the posts. This is not a regular forum, according to site rules links to answers are not answers if the link goes missing your answer becomes an empty shell without content. Answers should be substantial and stand on their own without relying on external data like links, videos or images. Instead of having users go through external links, either transcribe essential parts of the process here, linking the source, or posts these in the comments section instead.


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Why are mixamo animations messed up after combining them?
I am currently working on a baseball animation and I wanted to combine two mixamo animations that I have downloaded (idle and stepout). For some reason, the movement of the arms from the stepout animation gets completely messed up. I first wanted to solve the problem manually, because I read that there might be a mistake with the rotation of the arms however the whole animation does not show up on the Graph Editor.

I am quite new to blender so i would appreciate it if someone could help me out.
Thanks in advance

That's not really a qestion we can answer here. I'd suggest you watch a few short tutorials on combining Mixamo animations, such as this, this or this one.

To me, the crossed arms look as if there are different rest positions (e.g. T-pose vs A-pose). Make sure you select the same rest position (e.g. T-pose) for both animations when you download them from Mixamo.

Thanks a lot @Blunder. Indeed it had something to do with the rest pose. After I set the rest position to a T-pose it finally worked out.


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Understanding Loops: How does a loop connect vertices
I am trying to understand loops. In the manual (https://docs.blender.org/manual/en/latest/modeling/meshes/structure.html#loops) I read:

edge loops. They connect vertices so that each one on the loop has
exactly two neighbors that are not on the loop and placed on both
sides of the loop (except the start and end vertex in case of poles).

I start with a cube and connect on it's top and bottom two vertices making a diagonal edge:

I thought that in this mesh I should be able to get a loop selected containing the two diagonals and the vertical edges connecting them, since this would have at each vertex two edges on the loop and on both sides one edge that is not on the loop.
What am I getting wrong?

The 2 corner vertices on the top face (bottom-left and top-right) are neighbours of more-than-1 vertex of the loop (the 2 other vertices of the top face). I think that explains why its not an edge loop. Each vertex should have its own neighbour.

@Lutzi That is not correct, a diagonal connection on top and bottom should create a loop that can be selected. I guess pwp made a mistake connecting those corner vertices.

@GordonBrinkmann I selected the vertices and pressed F to "fill".

The question is how did you "connect" those two corner vertices at the top and bottom: with J or with F?
Beginners often use F, this is the New Edge/Face from Vertices tool. And this is exactly the problem, it only creates a new edge. The new edge only connects those two vertices and is not connected to the already existing face which the vertices are part of.

As you can see in the following screenshot after creating the new edge, when I select the top face it is still a single square face, only the boundary edges are selected, not the diagonal edge going across:

You could also select the edge nopw and delete it without getting a hole at the top. What you have to do instead is use the shortcut J for the Connect Vertex Path tool. As the tooltip shows, this tool "creates edges, splitting faces".

So after selecting two corner vertices and pressing J you can now select one of the two triangle faces at the top separately, and the new edge gets selected with it as well:

If you would delete this diagonal edge, you would have a hole at the top because now this edge is part of the two triangle faces. If you make diagonal edges with this tool, you can select an edge loop going around the cube diagonally.


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Help in modelling a cosmetic tube
I'm slightly new to Blender (using it after a long time and haven't been regular) and am currently working on modelling a cosmetic tube. I'm having a hard time aligning the bottle with the fringed end. Is there a way I can make these two cube objects be the same shape and get attached?

Now, this is the subjective part of the post and I'm not sure if this allowed here but I feel like the final result doesn't seem to resemble the product, although I have the general shape down. I feel like it could be an issue of the width of the tube, its very round at the top and very thin at the bottom - however, I'm unsure of how to correct this (if this is even the issue).
I used a reference image and, although nothing seems to be drastically wrong, it still doesn't look quite right. I'm also sharing the file temporarily in case it helps.

File:

Why are you connecting anything to anything at all? The tube is a single piece of plastic pressed at one end. It's not made of separate parts. I would start over. The trick is getting the form of the pressed part going to the round tube and the bumps at the end should be just an easy extrude operation.

@MartynasŽiemys I was actually kinda keen on starting over and making it one piece, but I wasn’t sure if I could add loop cuts just to the fringed end without messing up the rest of the tube.
If the loop cuts end up affecting the rest of the tube, would the extra geometry be an issue? I’m a bit nervous about getting more than I can handle.


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Is it possible to get a mesh to appear behind a specific object?
Here I'm using a reverse hull method to create an outline for this object, though I'd like for the mesh to appear behind the cat as shown here.

I'm aware this could be done with render layers but I'd like to have this work realtime (In the viewport).
Effect I get:


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Looping animation after the first animated scene
Completely new to Blender here. In fact, completely new to 3D modelling/animation and everything that has to do with it. And that makes it really hard for me to formulate this question, because all the terminology is new to me. But, i (think) i have created my first scene, at least done modelling, and i am ready to animate. Which made the modelling seem easy
The question at hand, is if there is any way to keep an animation going after the "main" animation? Like: Fram 1 (animation starts) -> Frame 250 (animation ends): but i want it to loop after Frame 250. Not the whole animation, just like the last 10 (or so) frames.
Only been doing this for 3 weeks, so please forgive me if the question seems dumb.

Look into the Cycles f-curve modifier. Also see https://blender.stackexchange.com/questions/242835/how-to-cycle-only-part-of-the-frames-in-an-animation and https://blender.stackexchange.com/questions/57394/how-to-specify-frames-for-%D0%A1ycles-modifier-in-f-curve-editor

Hey @DuarteFarrajotaRamos!
"Cycles* f-curve modifier" is like reading mandarin (i'm Norwegian), i am really new to this But i'll check out the links you added, thank you so much!


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Help with hip and thigh rigging

I'm working with this model I downloaded from Mixamo.  The rigging is mostly good but the hips and thighs are very messed up as you can see in the sample.  I show the mesh which looks detailed enough.
The center crotch area is being dragged and deforming the other inner thigh.  Obviously this shouldn't happen in real life spandex or bare skin.  The side hip-thigh crease is caving in a lot.  I think I need to either add bones and/or use weight painting but I'm not sure.  Does anyone have any advice?

Hello could you please share your file (only share the useful part)? https://blend-exchange.com/

The file can be downloaded from Mixamo.  The character is Jennifer.  Here's the full link.
https://www.mixamo.com/#/?page=1&query=jennifer&type=Character

It's hard to get the thigh to deform correctly with just one bone, so the usual practice is to add a shape key and a driver, it's called a corrective shape key.
Here is a tutorial from Royal Skies, the only difference in your case is that you need to set a different axis for the driver.
Also this playlist explains shape keys really well

https://blender.meta.stackexchange.com/questions/2382/what-is-wrong-about-answering-with-a-link

@HarryMcKenzie I know answering with a link isn't the best I can do, but should we answer questions that have been asked before with small changes? Should I send a link to a similar question/answer?

Thank you, I will give it a try.

probably mark as a duplicate maybe? Can you share a link that is similar to this?

I tried to use the shape key using the Royal Skies tutorial.  This isn't working for some reason in Blender 4.1.1.  I added a driver using the left thigh armature rotating on the Y axis and used the same expression formula he showed in the video and tried to change it a little but value always shows 0.  But the effect of the modification is left permanently on at max strength so that when I move the left thigh bone back to normal, there's now a big bulge in the left hip-thigh crease.  It looks good when living the left leg fully but anything else shows an increasing bulge.

Make sure that the expression works and the variable has the right name. You can pick the right equation yourself to make the Shape key change from 0 to 1 in 90 degrees of rotation.

I finally got it working somehow by using the XYZ ruler, and using the Z axis rotation even though the bone was clearly rotating the Y axis.  In fact when I hit R and Y, it rotates it how I want.  But in the XYZ Euler, it was showing a number changing from 0 to 1 in the Z rotation axis.
I had already applied rotation to the armature because it came from Mixamo pre-rotated.  But it still changed on the Z axis as far as the Driver was concerned.  I ended up using the formula var * 1.4.

@GeorgeOu Rigging can be hard, and why the axis was different than you'd think is because bones have mean tilt and local rotation, you can see this by enabling the axis overlay in the armature/bone tab.

I guess there are several solutions, like creating a shapekey that will correc the bad deformation, with a driver to trigger the shapekey, also you could create another bone that will control this part. At last you could give a Smooth Corrective modifier to your object, you can limit its effect on a vertex group only:


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How to bake an animation with modifiers in Blender?
Im making an animation in blender. The issue is that the animation can't be baked because of the modifiers. I've tried other methods like exporting it in mdd file or skrinkwrap framing but those two don't work as im animating a water mesh. I would love to hear some suggestions like blender addons that can bake all kinds of animation or other methods.

apply the modifiers and then bake?

I guess you mean it's not an armature animation, but instead a mesh generated animation?
In that case, the answer is simple: export to Alembic.
It quite literary bakes your mesh "as is" on every frame (or even subframe if you ask for it). It's the go-to format in VFX industry for pretty much everything.

I found this answer too while experimenting on stuffs. Thanks anyways.


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How to change UI text depending on language settings Blender Python
I wan't my addon to be on multiple languages, how could I do it? taking for example a label
layout.label (text = 'use')

if the user has configured his blender in japanese I would like a japanese version to appear on the UI.

You don't have to add anything, the layout.label function has a default translate argument that's True. It will automatically fetch the translation from the builtin dictionary.
Link to the docs

Of course, provided the word has been added to the dictionary in the target language.
Here's the result of
layout.label(text="Use")

Source/Interface/Internationalization has specifics on the rare cases where you do have to deal with it as well as an explanation for how to do it.


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Blender Python | How to make an Enumerator with images preview?
I've seen in plenty of add-ons how they draw in the Gui an enumerator with small preview images (ex. Easy PBR material preview, Botaniq asset selector, etc.). I tried to "reverse engineer" it, but to be honest I can't even start to comprehend how it is done nor I could find a tutorial or an explanation online. may someone explain how can I code that?

You may want to start by looking at the ui_previews_dynamic_enum.py template available in blender (keep in mind this template only previews .png files based on line 48 if fn.lower().endswith(".png"):).

Oh, I see, I'll check it out. Thanks

This is answered here https://blender.stackexchange.com/questions/155135/how-to-display-an-image-in-blender-ui-with-python


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How to get a Value fill the entire image?
Let me explain. I want to get a specific value from the z buffer (the closest pixel of a specific object to the camera) and then fill the image with that value in order to Run a Less than Math operator to get a mask of the objects are in front of my object. but I can´t find a way to do it. here is an image of what I´m trying to do. sorry for the convoluted explanation.

You're using cryptomatte, but AFAIK it doesn't have anything to say about actual depth.  Have you enabled View Layers -> Passes -> Z?

I think what you want is that Z pass into math node or color ramp


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I Want to separate grease pencil in compositor
Is there a Way of isolating the grease pencil like the freestyle pass or cryptomatte?. I can't find a way of doing it.

Store Grease Pencil objects in Collection and control visibility via View Layers?


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Camera projection with geo-nodes
I’m trying to create camera projection with geo-nodes to store image color on point cloud color attribute, but I’m not into trigonometry at all.
What I’d like to achieve is this:

But with geo-nodes - not on a shading level.

Is rephrasing your objective as what follows is correct ? (1) You have an image, imported as an object (a plane ?). (2) You have a point cloud. (3) You have a camera set to look at the image (1) through the point cloud (2). (4) You would like to colour a point according the background pixel seen in line "behind" it.

Could you provide your Blender file using https://blend-exchange.com/ with image and point cloud ?

@StefLAncien, seems I made it work. I shared file in answer. Thanks!

Seems I did it with new 4.2 matricies nodes combining setup I had in shading.

Inside geo-nodes there are 3 drivers - to get camera angle and shift x/y for proper mapping. So to use in defferent scene - be sure to remap those drivers to scene camera.


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Replay type fluid simulation not working as expected. What am I doing wrong?
Replay type fluid simulation not working as expected.
Hello everyone, I am following a tutorial from a book, on fluid simulation. I am expecting the simulation to have been baked after the first run and should be replaying on subsequent runs using the Timeline editor.
This is not the case as the frame rate of subsequent runs is the same (as that of the first run as you will see in the screenshot which is one of the subsequent runs and still running at a 0.78 fps).
I am assuming that the cause of the low frame rate is that the subsequent runs are redoing the calculation, hence the simulation is not baked. From the blender manual,
Type
...
Replay
The cache will be baked as the simulation is being played in the viewport...
My Question: I assume this means that the first run already did the baking, what could I be doing wrong that makes the subsequent play in the timeline to redo the baking?

it is only baked if you hit the "bake" button, else it is "just" cached. So if you change anything in between - Blender calculates again and it will be slow again. The difference is: if you change anything after you hit the bake button, you will see the "old simulation". If you make changes, they won't be considered until you hit the bake button again.

@Chris I played it repeatedly without changing anything. Does that mean that it recalculates even when nothing is changed?


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Simulation of water in a bottle
how do I do a simulation of water in a bottle. So that it turns over there relative to the position of the bottle. Thanks)

Hello, what does the fluid simulation give?

You should provide context and tell us what this is for. Show some images and screenshots of what you have and try to describe what you are after, maybe show some examples of what would be an acceptable result. The answer depends on what you need. It's possible to just simulate the level of the water changing, it's also possible to simulate water splashing around.

Hello, Паоло, welcome.  .. there are lots of ways to fake/simulate this.. which to chose will depend on the style of your result. Please include an illustration of  the kind of water and bottle you want to create, indicate whether the water should splash, or just remain level, etc. Your description turns out to be not specific enough.


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Path Animation of a collection containing bone animations (steam locomotive with movable wheels and rods)
How can I achieve that a steam locomotive with a) rigid parts such as boiler, chimney etc., b) rotating wheels and c) movable rods which are animated depending on the rotation of the wheels and parented to bones will follow a path?
I understand that I can select all objects in the collection "locomotive" (by the way: only as long as they are visible...!) and parent them to e.g. an empty, which then can get a Follow Path constraint and will "tow" the parented loco parts, but when I do this, the movement of the rods is gone (they stand still and just move together with the whole loco, while the movement of the bones continues). I guess that this is probably due to double parenting, since the rods are at first parented to their bones and now parented to the empty. Is there a standard method to overcome this issue?

There isn't such a thing like double parenting, the rods you're speaking of are now just parented to the empty. Leave anything that's parented to the  armature as is and just parent the armature to the empty. If that doesn't help, it maybe helpful to see some pictures or even better your blend file.


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How do you find the active element of an object's edit mode components (verts, points, faces, loops, ..whatever) using python?
Where does blender store the information for the active element for an object?
For example, I can tab in and out of edit mode for a mesh, and the active element remains the same. This is the same for various non-mesh object types as well. The program is keeping track of which element is active somewhere, and I'm looking to figure out where that is and how to access it (specifically from a python script). I am aware that, specifically for a mesh object, you can convert the thing to a bmesh and use the selection history to get the last selected item (i.e. the active one), but this is specific to only mesh objects and does not really have anything to do internally with the active element. (It is just a workaround that gets the desired result cause the last selected element just so happens, also, to be the active one.)

bpy.context.active_object

The title and body of your question seem like they ask two different things ? Do you want to track the active object or do you want to track the selected components of the active object ?


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Model not rigging properly
When i move body parts of my model there are some vertices that dont move when i rig the model, someone knows how to fix this??

It is hard to tell just from the screenshot. Have you checked the face normals and the weights in the vertex groups?

The weight painting is all blue


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Blending terrain tiles
I have terrain tiles that have normal maps and diffuse maps for their shaders, and separately, subdivison surface modifiers along with separate HeightMaps used in their separate displacement modifiers.
My question is: how can I effectively "blend" such terrain tiles so that they look reasonably smooth?
One thing I tried is applying all modifiers. Then, there is a small bridge-edge-loops option to blend terrain, but at varying distances, this will either distort the diffuse maps too much or make the landscape look too stretched at far distances apart.
So what's the solution here?


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How do I get this Geometry Nodes Hair Generator working?
I downloaded this free Geometry Nodes Hair Generator from here:

https://xeofrios.gumroad.com/l/gnhair
https://80.lv/articles/developing-a-custom-hair-creation-system-with-blender-s-geometry-nodes/
https://www.youtube.com/watch?v=XY5j4_BHU2A
I'm using Blender 4.2.1 but I can't get it to work. I select the hair, go into edit mode, draw the curve (like in the video tutorial), but the hair doesn't appear. What am I doing wrong?
Thanks in advance.

You edit the wrong object. Note that the Hair is a Curves object. This is a new curve type for hair curves (Blender 3.3). The Curve object (type Curve, without s) is the old Bezier/Poly/Nurbs curve type. They are similar. The Hair object has a Geometry Nodes modifier on it. If you look at the very first node on the left you see it uses the objects in the Guide collection. So, the Curve and the Mesh objects are used to create the geometry for the Hair and its own geometry gets replaced ==> edit the Curve object to create the guides, not the Hair object.

Thanks a lot friend, that solved the problem! In the video tutorial they didn't show which object they had selected, that's why I couldn't get it to work.


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How to invert the selection while keeping the previous selection?
How can I select the same faces on the right side, which are selected on the left side? I know I can select the rest of the faces little by little with "shift", "c", or "b", but I would like to know if there is something easier, so I can apply it in future projects. Thanks in advance.

In the Select Menu you can find "Select Mirror" (Shift Ctrl M).
Tick the "Extend" option in the "Edit Last Operation" Tab (in the left bottom, a black box, F9 to recall it) if you want to add to the previous selection.

Omg, this really worked, thanks so much for your help! This setting was really hidden! Thanks again!


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Baking AO map with Python in Blender 3.0
I'm fairly new to Blender and I've been looking for a way to bake an ao map using python with blender 3.0. I've been trying to adapt this code to the new version of blender, but I'm struggling
import bpy

ops = bpy.ops
scene = bpy.context.scene
mesh = bpy.ops.mesh

# Delete default scene objects
ops.object.select_all()
ops.object.select_all()
ops.object.delete()

# Import the model from our Three scene
ops.import_scene.obj(filepath="input.obj")

current_mesh = scene.objects[0]

# Set it to active and go into edit mode
scene.objects.active = current_mesh
ops.object.mode_set(mode='EDIT')

# Mesh cleanup step, since what's coming out of Three is mostly cubes laying side by side.

# Remove double verts...
mesh.select_mode(type="VERT")
mesh.remove_doubles()

# Merge tris into quads...
mesh.select_mode(type="FACE")
mesh.dissolve_limited()

# Remove interior faces
mesh.select_all()
mesh.select_interior_faces()
mesh.delete(type="FACE")

# Create a second UV layer for the ambient occlusion map
bpy.ops.mesh.uv_texture_add()
current_mesh.data.uv_layers[1].name = 'Shadows'

# Unwrap the mesh
mesh.select_all()
ops.uv.lightmap_pack(PREF_IMG_PX_SIZE=512)

# Create a new image to bake the lighting in to
bpy.ops.image.new(name="AO Map")
image = bpy.data.images['AO Map']

# Set the image to active (applies it to the object)
bpy.data.screens['UV Editing'].areas[1].spaces[0].image = image

# Bake the lightmap
bpy.data.scenes["Scene"].render.bake_margin = 4
bpy.data.worlds["World"].light_settings.use_ambient_occlusion = True
bpy.data.worlds["World"].light_settings.samples = 10
bpy.ops.object.bake_image()

# Save the baked image
image.filepath_raw = "output.png"
image.file_format = "PNG"
image.save()

# Save the new model with the new UV channel
ops.object.mode_set(mode='OBJECT')
bpy.ops.export.three(filepath="output.json")

For now, I replaced the 18th line by :
current_mesh = bpy.context.window.scene.objects[0]
bpy.context.view_layer.objects.active = current_mesh

there is also a problem with this line that i havent been able to solve
current_mesh.data.uv_layers[1].name = 'Shadows'

As you can see from bug report there is no attribute 'image' in 'SpaceOutliner'. So maybe it's more simple to use nodes? you can connect texture via node and start to bake.
For node connection you can read example here.
Connecting a texture node to a material node via the Blender Python API for Blender 2.82
Something like this
mat = current_mesh.active_material
mat.use_nodes = True
matnodes = mat.node_tree.nodes

tex = matnodes.new('ShaderNodeTexImage')
img = image
tex.image = img

disp = matnodes['Material Output'].inputs[2]
mat.node_tree.links.new(disp, tex.outputs[0])

Also maybe instead this
    # Bake the lightmap
bpy.data.scenes["Scene"].render.bake_margin = 4
bpy.data.worlds["World"].light_settings.use_ambient_occlusion = True
bpy.data.worlds["World"].light_settings.samples = 10
bpy.ops.object.bake_image()

Use this
bpy.context.scene.render.engine = 'CYCLES'
bpy.ops.object.bake(type='AO')


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interactive 2D animation for the web
Is it possible to make an interactive 2D animation in Blender? For example to let a car drive (over a map) along a path and let it start or stop by clicking?
And if yes, can this be exported for the web?
Even better:  can a 2D picture (a piture of somebody for instance) go through a 3D enviroment along a path by mouseclicking?
Or is this an awkward idea and should I better use other software?

Blender is better for creating the car and animating it, and finally exporting it.  It isn't designed at the moment for interactivity.  Typically people are working with some other software such as Unreal, Unity, and UPBGE, to create what you are describing.

Thnx,   I just noticed that UPBGE is the new game engine that works together with Blender. So you mean that when I bring in the 2D animation made in Blender, I can make it interactive in UPBGE. And can't I make an interactive Web aplication from the 2D Blender animation with Verge3D (inspite of the name)?

The website says it is compatible. I have not worked with Verge 3D so I can't answer questions about it.


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Animation Action
I'm new to Blender so probably I'm asking a stupid question.
When I export an FBX with some Actions baked in, I found in the baked file a lot more Action than what I expect. It seems like the original action has been applied separately to each object that was part of the animated group (Parented objects) and baked consequently.
Can someone help me to find the correct way to bake a file of for example a drawer with all is in it with an action for the opening and another for the closure?

Open NLA Editor and add all necessary actions here:

In FBX export settings, uncheck All actions and check NLA Strips:

This will export only actions added in NLA editor

Thank you Crantisz for your help; i'm gong to try it immediately.


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water refraction
I am a beginner user of blender and I hope that stack exchange not only is for experts.
I like to "make" a swimming pool in blender / eevee with water and refraction , without animation and without rendering .
It works with the glass BSDF or with the principled BSDF , but there is always a dirty grey "shadow" appearing .
The only way to get rid of that "shadow" is to disable refraction .
I suppose that it will only be possible with compositor and rendering , but I dont want to render .
Can someone help me ?

Hello, could you please show a screenshot to show what you mean? maybe share your file?

Reflections and refraction interacts with ALL that is visible in the scene, including the background that is grey by default. But if you don't want to render, then why do you care about how your shading reflects its environment? What are you trying to achieve?


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Accessing custom property of mesh data through Attribute Node in Shader Editor
Accessing custom properties of object data through the Attribute Node works just fine but custom property in mesh data does not. Even though the documentation says:

The name or path is looked up first in the object data-block, followed
by the mesh data-block if not found.

Since my object contains a mesh and the custom property I look for is defined only in the mesh level, i was expecting to be able to access it through the Attribute Node but Blender does not seem to find it.
Am I misunderstanding the doc ?
Documentation also talks about "path". Maybe I can access the mesh custom property through a specific path, I tried to copy-paste data-path / full data-path but sadly it does not work. Any idea ?

I assume it's because object properties are evaluated only once with the mesh they are using, but on the other hand it looks for values on each individual vertex of the mesh in case you choose Geometry in the Attribute node. Long story short, you can access it but you have to first convert it either into an attribute stored on the mesh or on a vertex color layer, but you are limited to 8 maximum. Both can be done with python scripting


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Why my WorldOutput trun all hdr map to one-colored
I want to use custom .hdr file as enviornment map, I do this:

as you can see, my env is no image but one-color(now is a gray, when I change hdr file, it change with the file), why?

You used an Image Texture node instead of an Environment Texture node. Always use Environment Texture for HDRI's.

thank you, sorry for so silly question.

@Z.Haw By the way, I sometimes experience that when I somehow messed up the Environment Texture so that it doesn't work although the node setup looks correct, I have to open up the HDRI file again with the open dialogue. Just reloading via Alt+R doesn't help.


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How can I bake animations in geometry node(using drivers)?
I driver to translate the position of the cube, and I click Object-Animation-Bake Action to bake it , it works fine.
But when I use driver in Geometry node (for example: using "#frame/24" to drive a roatation value of Rotate Instance Node), and try to bake again. The animation is empty(have keyframes but have no animations).
Why and How can I bake drivers-made animation in geometry node?

AFAIK you can't. Hopefully they will build something for it like "visual" keyframing.

@Chris thank you very much.

At the moment there is not a way to bake into Action (f-curve).
In this simple test of Cube rotation ...

You can convert into Shape Keys per frame by exporting as Light Wave Point Cache (.mdd) format.
Enable export addon under Preferences and export selected object as .mdd. With the Cube selected (without modifier) Import .mdd back.

Or export object as Alembic (.abc) file format and import back ... stored under Mesh Sequence modifier.

That is not the same as baked action into f-curves), but it is what it is :)


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Hi I download a human model with "bone roots" but no Armature in Blender, how can I make "bone" to armature?
here is my model node:

I wonder how can I make those bone root to Armature.

These "bone roots" are Empty objects. You can use their position and rotation to create the bones of an armature, either manually or with a script (https://github.com/artellblender/empties_to_bones). To get the correct size of the bone you probably need to use 2 Empties to place the bone's head & tail. It shouldn't be hard to create a script that does this if you are familiar with scripting. But the generated rig is very simple. For animation, I rather would use an animation rig like Rigify, Cloud Rig, Blenrig, etc. These rigs offer IK controls and a lot more to make animation easier.

@Blunder thank you so much, Im a totally beginner on Blender. And your answer solve all my confusion clearly.


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How to get Normal and Position using Capture Attributes Node
Waht I do:

In my case, I capture Index using a Capture Attributes, and then put the value to a Noise Texture. It works fine. You'll see the IcoSphere distorted.
And then when I change the Index to Normal / Position, I got a IcoSphere without distortion.

My Questions:

Why it works with Index but Normal&Position fails.

In your second example, your Set Position node is still linked to the geometry output of the first Capture Attribute node--which is getting the Index information but not doing anything with it. As noted in the manual, you need to use the geometry output of the Capture Attribute node you get the information from for it to have an effect.

P.S. You don't need the node at all here in this case, it's redundant:

oh, thank you. I really made a silly mistake. And still learn sth else from your answer. BlenderStackExchange answer anything I wonder, so nice of you guys.


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What is real input of Noise Texture Node in Blender Geometry Node?
What I did:
I have a Node to create some cubes base on the position of a points of an ico sphere.
Image here:
What I Met: And you'll see I connect a Noise Texture to a Add Node and a Scale Elements node to Transform the cubes. When I change the Scale of my Noise Texture. The Cube's Position randomized to a new positon, but scale always same.
My Question: Why when the input of Noise Texture Node is Same, but one output are randomized numbers, but another oputput are same value.

i think it's because of your instance on points not has scale 1/1/1

Plug the scale to your scale of instance on points.

oh, you're right. Thank you, but why? I can not using a Scale Elements to scale it before plug to Instance on Points?

@shibi: i am not sure why. But if my answer helped you, please click on the checkmark left of my answer. thank you. Just by trying out it looks like scale elements cannot scale different values, except you use that selection input. and for that what you want the scale value in the instance node is perfect, no need to scale it before.

thank you again


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black rendered imagine
i have a problem with rendered imagine - its all black, and i cant fix it, i checked everything what i knew could be wrong, and i tried find help in youtube tutorials, but its still the same... i tried to make render in cycles - i usually do - i made maybe 10 renders, and suddenly i have black renders, i didnt change anything, in eevee is the same problem could anybody help me? i have to finish my project as soon as possible

I'm afraid you haven't given us enough details to even guess at what's causing your problem. Please at least provide a screenshot of your Blender window (the 3D View one, not the render output). See: How to upload an image to a post. You can also use the top Search bar here to search for posts with similar problems to yours. - There are lots of them!


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False Color Objects by Size
I have a mesh which is clearly made up of several loose components. I want a way of applying a rainbow colour ramp to the mesh to act as a 'heat map' for component size. I would like to apply this in a systematic way to the components so that 'big' are to one end of the ramp and 'small' to the other. I can false colour components randomly easily enough, but I cannot figure out how to do this systematically by size. There must be a simple solution, but I cannot figure it out. Thanks!

If you're talking about "size" in 3D you could be talking about different things? Volume? Height? Mass? Width? I assume you mean volume?

Hi! Yes true, any of those could be metrics for size. But let's say by volume. Do you know any shader configs?

I used the GeoNodes setup from this answer to calculate the volume of your meshes. I only added the Mesh Island field node as the Group ID input for the Accumulate Field node; calculating the volume for each separate element of the mesh. Then I just mapped the range of those from 0-1 with the Map Range node.

Then you can just store that value in a Named Attribute and use that as a gradient for a color ramp node to color your meshes according to their volume.

Great answer! I found the other answer as well but had no time to really investigate it.

@GordonBrinkmann it's pretty funny cause that answer is actually a recreation of another regular stackexchange answer about how to calculate volume in code. So we're just creating a chain of answers expanding on other answers into infinity.

Yes, I've seen that  Well, keeping it up to date

Thanks for your answer @Jakemoyo! It looks like this is what I need to do, and have tried, but it is still not working for me. I am sure it is a simple problem, but I cannot figure it out. Could someone please take a quick look at my blend file and node setup?

Looks like you don't have anything plugged into the attribute statistic node. You need to connect the Geometry input into that. I'm not switched to the newest version, so some of your nodes are coming up undefined on my end. But I'm pretty sure that's your problem.


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Skecher import add-on error
I am trying to import the add-on Sketcher import. On Blender add-ons it is supported on version 4.2 and later, my version is 4.4 gfor ARM architecture and after imported a pop up window appears with a error message.
Any clue about that.
Thank for your time and cooperation
Kind regards

What error message? If you mean the CAD Sketcher addon, it probably links to binary components, and as such is platform dependent. Very likely no one compiled a version specific for ARM devices, especially considering how relatively new support is.

Thanks Duarte. I made mistake the problem is with Sketchup and not with Sketcher. I find more information on https://extensions.blender.org/approval-queue/sketchup-importer/. I will do some tests following some recommendations

It works on X64 architecture


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Why is my colour not the same, despite having followed a tutorial
I'm relatively new to Blender VFX, and I've been following a tutorial. When he uses base colour and emission colour, I do the same, but my colour is not the same.

I've looked for other posts about this but can't find anything.
I know it's not really a big deal, but I do want to know why this is.
Any help would be much appreciated :)

I guess they have different Color Management settings in the tutorial.

Ah ok thanks :)

It worked! Thank you so much! :D @gordon-brinkmann

Please post the answer to the question as an answer, so it won't show up as unanswered anymore. :-)