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Achieve Escher holding sphere, but with real image
I'm trying to achieve a specific effect based on the idea of the famous Escher "Hand with Reflecting Sphere" image, but instead of reflecting a modeled environment, I want it to reflect a real image of myself holding the sphere. I first saw this effect 25 years ago in the video The Mind's Eye, which contained a part an animation called "Prime Corporate Video".
You can see specific part of that video here:
http://www.youtube.com/watch?v=GP2g4uprgx4&t=4m3s
I've always wondered exactly how that animation was made since I first saw it 25 years ago. The animation was made in 1986 so I don't think the hand in the video was rendered, so maybe raytracing wasn't even the technique used and it was just some photography/greenscreen trick.
Either way, I've been trying to reproduce a scene like this and haven't figured it out. I usually end up with image mapping issues like circular regions that look distorted and the sphere reflecting part of the background instead of only the real image.  I'm wondering if maybe I have to use some tricks with render layers.
Below is an example of what I've been able to produce using a world background image using "Object" Texture coordinates that have been vector mapped 0.5 xyz location, rotated -90 on X and scaled x 0.3 and y -3.9. The background is just an image on a plane sitting behind the sphere.  This is all done using nodes in Cycles.
Any ideas?

tried to map your image on the sphere with reflection texture coordinates on a diffuse or emission (no glossy)?

A good idea and this does get rid of the problem of the background reflection, but this won't work when I add the hand object (based on my hand) into the scene because it won't be reflected.  Also, the image distortion problems still exist.

Related: http://blender.stackexchange.com/q/2030/599

The original 1986 animation? A selfie. He is holding the camera in his hand, then used something like a fisheye lens to distort that to create the video. You know they were making visual effects on film before computers ;) Even without rendering you can take a selfie and distort it in the compositor or gimp/ps.

Perhaps and I am open to that possibility, but the company that made it specialized in 3D rendering. If you watch the beginning of the video as well there is a similar animation that turns into a more obviously 3D rendered scene, but still with real video elements. How can you explain that his real hand is being reflected so precisely in the virtual sphere?  And the lighting matches exactly. They were not making hands/scenes and people this real back then. If you watch these two animations frame by frame, you'll have trouble believing it was just a photographic trick.

Do compositing using a lens distortion node to give a bit of sphere effect on your image, add this to your rendered glossy sphere with modeled arm with the sphere objectID as factor/mask

the render of the sphere and hand has to use a black background (because you'll add your reflection) and also you have to check tranparent in render settings/film options

Thanks for answering, but your solution is more of a work around than trying to find the correct texture mapping I was looking for.  Either way, I'll accept your answer since its the only one.


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Scaling keyed video with alpha over generates black border
I'm working on a green screened project and am scaling my foreground video then passing it into a keying node, then alpha over. The problem is, the area outside the scaled video is black not green, so it ends up masking out the background video. Is there a way to make the area outside the foreground video be alpha?

I think we can use an alpha over node to combine a green background image with you existing greenscreen. Can you please upload you .blend?

Actually, using a mix node between scale and keying worked. I'll post the solution.

At least in this case, adding a mix node between the scale and keying nodes that mixes the foreground video with the green screen color extended the green color to the original size of the foreground video.
This raises the question of what if your background video is larger than your foreground video to begin with.

source: Stack Exchange

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

sort: votes


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Can you use another material as input to material nodes in cycles?
Is it possible in cycles to use setup a material node to take the output from another material as input into a mix shader?  This way if I change the configuration in the other material it updates both materials?  Or do I need to do this another way?
I'm surprised nobody has asked this already and can't find anything online so maybe it's not possible.

Ah yes that works and is different from what I thought a node group was for.  Didn't realize it created an output that was available in different materials. Thanks.  Did you want to create an answer for this or should I?

That's a typical use case for Node Groups.
Select all relevant nodes and group them with Ctrl+G. This way the created group is accessible within all material node trees, located in the Add menu: Shift+A > Groups > Your Group Name.

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


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How to emit light from base color of a wave texture node?

So as you can see I am trying to recreate the added picture using wave texture node and I want only the red color to emit light. So that to do? and what should be the node set up?

If you want the red part to emit light, use the black and white component from your Wave Texture as the Mix Factor Between a red Emission Shader and whatever you want the rest to be (I left it as a default principled BSDF with a black BaseColor, but you can use whatever you want.)


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How to move the gizmo of a section?
How to move the gizmo of a section of to make a scale (NOT relative to the center of the selection)? When I do it with the cursor it crushes all in 1 single point

Hello. From which part do you want to scale?

When you say section, I assume you mean selection or group of objects (more than one object).
First you move your 3d Cursor from the origin (0,0,0) to where you want to center your transform.

Then select your objects, set "Transition Orientation" to be relative to "Cursor", than any rotation or scale or move will be relative to that cursor point.

(please if this is your answer, please mark it as ANSWER so I can build credits)

I want to move the gizmo from a selection of edge to the left in the center of the mesh of the mesh then scale

there is no way to do it, except after making the selection and placing the cursor (i couldn't find how to move the cursor to the selection gizmo except by hand) then edit from there .
In Maya you unlock your gizmo, you move it where you want (do not modify the selection) then relock and you make the modification.

I would place the cursor first, then make the selection.   In an example (https://blend-exchange.com/b/Qw2vX3Jo/), I set the cursor to a selected vertex on Sphere.001, set transform pivot point to 3d Cursor, and then a rotate or scale is relative to that point.   I the VIEW tool, you can see the XYZ position of the cursor and change it precisely.   Or you could create an empty, position that and align the 3d cursor to the empty.   If this is nowhere near what you are looking for, then you might want to add detail to your description, especially a screenshot.


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Area dragging not working
The corners that would usually allow me to drag and create new areas from (along with joining or swapping them) isn't working. No marker shows up when I hover over the corners, and I only get the resizing options.
I checked to see if the controls/keybinds were messed up, but nope..  it's still "ActionZone Area" ..
Any fix to this?

Hello, what blender version are you using ?

i'm using version 2.83.5


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How do i connect points A to B following the sphere curve, and then add some height ad midpoint of the curve? (Flightpaths)
I have been really struggling past couple of days on how to connect the points of A to B, and create a nice curve line between the points. I want the midpoint of the curve to be elevated, so as to create flightpaths where the midpoint of the curve between point A and B is elevated the most, after which the curve bends down again until it reaches point B.
I have a problem understanding how geonodes work for this seemingly simplistic question, and have tried many things, but I can't figure it out.

Could you provide an other Blender file with a decimated "BlackMarble_2016_3km_gray_geo" mesh ? I don't know what's going on, but using Blender 3.6.5, just reading then writing your file saves a 35Mb file, that I can not upload to share it with you. If not, I will replace this with a simple grid...

Not related to your question: I notice in the console that you have 2 dependency cycles because "BlackMarble" is "shrinkwraped" on "OtherAirports", then "OtherAirports" are "surface deformed" on "BlackMarble". May I recommend to remove those cycles ?

Not related to your question: As you commented below, "the sphere is not a perfect sphere on top" because the origin of the plane you are making the sphere from with two SimpleDeform modifiers is not at this plane centre. It is put actually on Schiphol airport. Just by shifting in Z direction all three objects by 52.308 (based on your data), then "Applying" the new "Location" should solve this minor issue.

Not really a duplicate, but it reminds me of something that has been built before: https://i.sstatic.net/kGjTd.gif ..You can find the blend file at this post: https://blender.stackexchange.com/questions/248064/

Using geometry nodes:

This first part builds a curve and set its point positions on the target airports.
Then it subdivides the curve and associates the center airport position to the points associated to this subdivision.
As it makes doubled segments, convert to mesh and remove doubles.
Second part:

Split edges and come back to curve in order to have one spline by air flight.
So that we can use the spline factor to adjust each point position.
 (Blender 4.0)

Wow, thank you so much! I wil try to retrofit that to my specific case, and will let you know if it worked. Thanks!!

You'll need to know the sphere radius and the airports should be centered to their origin (sphere center).

I tried to apply it to my data and changed it in this blend file

But I dont know where it goes wrong....
Ill note what might make my data different...

The points are imported, and transformed to a sphere using gisplugin
I then "guestimate" how big the sphere must be in order for the points to align  just in top of it.

You noted i need to know the sphere radius (4250 as dimensions are 8500m each), but I dont know what to do with that info, how to apply it.

Shiphol object should be on the sphere (not a vertex only on sphere), or sample it to get the location. Here is an adjusted file. But Blender is not easy which such distances (viewport rendering suffers a bit).

or this one should be better

Also, be sure to adjust the "resample curve" length appropriately to your model size as if not you'll generate many points (i've set it 100m in the last file).

Wow thanks! But just to learn, what did you do different in the last file you shared , where the location is exactly on the sphere? And the file you shared 3 minutes before that?
Im looking at the differences of both files but cant find what you did different :)

I've adjusted this part: https://i.sstatic.net/Lw12W.png

(Using Blender 3.6.5 and Geometry Nodes)
NB: This answer is under work and has yet to be fully documented...
Objective
Build Bezier curves connecting pairs of points on a sphere, controlling mid-point height.
Approach

The GeometryNodes modifier is added to the object made of vertices put at the targetted airports position (named OtherAirports in the demo file).
1. Sphere properties and hub airport (named Schiphol in the demo file) position are recovered from objects specified through the Group Input node (label 7).
2. A single edge per targetted airport (label A) is build to connect it to the hub airport (label H).
3. The perpendicular bisector to those edges crossing the sphere centre is used to shift outward the mid-point. These points are collected as a point cloud.
4. Edges and apex points are combined in broken lines made of three points and two edges.
5. These pairs of segments are converted to Bezier curves, which handles are modified to tune the flightpath shape.
6. Control parameters are:
6.1. Height: Fraction of the circular arc connecting H to A used to shift the apex. A value of 0 puts apices on sphere.
6.2. HubAngle: Additional angle between the curve tangent and the edge connecting H to apex. Positive values increase "take-off" slope.
6.3. ApexWeight: Factor controlling the radius of curvature at apex. 0 is the default value. -1 makes a sharp angle. Positive values yield flatter curves.
6.4. AirportAngle: Additional angle between the curve tangent and the edge connecting apex to A. Positive values increase "landing" slope.
Process data

1. The centre of the sphere (labelled C) is computed as the middle of its bounding box.
2. The hub airport position (labelled H) is recovered with a Sample Index node set in Point domain. It is assumed that the hub is at Index 0. This procedure is robust if there is more than one vertex in the input object, and if the vertex is moved from the origin.
3. The sphere radius is computed as the distance between points C and H.
Build direct paths

Direct paths are segments connecting the targetted airports (labelled A) to the hub airport (labelled H).
1. Using an Instance on Points node, a single edge is put at every vertex A of the Airport mesh provided by the Group Input node. As the Mesh Line Start Location is (0,0,0), the position of the Index 1 vertex of an edge (labelled V1) is equal to the position of the associated point A. The Offset parameter is irrelevant, as the position of the Index 2 vertex (labelled V2) will be edited afterwards.
2. Through a Realize Instances node, instances are made independent edges.
3. The position of the vertex V2 of every edge is set equal to the position of point H, provided by the Group Input node.
4. Because it is downstream the Realize Instances node, the Set Position node modifies the Point domain. So the Index tested to define the Selection mask is a Point index, not an Instance index.
5. Through a Capture Attribute node set in Edge domain, the index of vertex V2 is recovered to be compared to the actual point Index. Its value is provided by an Edge Vertices node.
Compute apices

Apex is the highest point of a flightpath.
1. A point per direct path edge is created using a Mesh to Points node set in Edges domain. The procedure to compute its position follows. These points are collected in a Point Cloud. It is to notice that an edge and the associated point are sharing the same Index, but in different domains.
2. The mid-point position of an edge [AH] (labelled I) is computed from its two end vertices, which position is recovered with an Edge Vertices node.
3. The perpendicular bisector of [AH] is computed by subtracting the sphere centre position (labelled C) to the mid-point I position, because points A and H are laying on the sphere. So $\vec{CI}$ is perpendicular to $\vec{AH}$.
4. This vector is normalized to be scaled afterwards by the apex height. This height is a function of the length of the circular arc connecting A and H. Let $\Delta \theta$ be the angle between $\vec{CI}$ and $\vec{CH}$, and $R$ the sphere radius. The length of this arc is then $2 R \Delta \theta$.
5. $\Delta \theta$ is such that $\cos{(\Delta \theta)} = \|\vec{CI}\|/R$.
6. The distance between point C and the apex is defined as $(\kappa \Delta \theta + 1) \times R$. The $\kappa$ parameter is user-defined, and its value is recovered through the Group Input node. For $\kappa=0$, the apex is on the sphere ; for $\kappa=2$, the apex height is equal to the distance between A and H along the sphere.
7. The apex position is defined from point C, by adding the vector computed at step 4. So by construction, points C, A, H and the apex are coplanar.
Build over paths

Over paths are made by combining direct paths end points and apices in sets of two edges.
1. A Mesh Line with two edges sharing one central vertex is duplicated as many times as the number of direct paths. Start Location and Offset parameters are irrelevant, as vertices position will be set afterwards. It is to notice that the Duplicate Elements node is set in Instance domain. This way, duplicated edges remain connected. Whereas in Edge domain, this connection is lost as two vertices are created at the junction. So the three vertices of copy number $i$ are with indexes $3i$, $3i+1$ and $3i+2$.
2. Through a Realize Instances node, instances are made independent sets of edges. Subsequent Set position nodes are thus in Point domain.
3. Point H is copied as the first vertex of the $i^\mathrm{th}$ copy.
3.1. Its index matches the selection mask $3i$.
3.2. Point H position is recovered with a Sample Index node set in Edge domain, looking for the $i^\mathrm{th}$ direct path. As point H was recorded at second position by the DirectPath node group, its coordinates are provided by the socket Position 2 of the connected Edge Vertices node.
4. The apex (labelled T) is copied as the second vertex of the $i^\mathrm{th}$ copy.
4.1. Its index matches the selection mask $3i+1$.
4.2. Point T position is recovered with a Sample Index node set in Point domain, looking for the $i^\mathrm{th}$ apex.
5. Point A is copied as the third and last vertex of the $i^\mathrm{th}$ copy.
5.1. Its index matches the selection mask $3i+2$.
5.2. Its position is recovered as for point H, but from the socket Position 1.
6. The normal to the plane defined by (H,T,A) is computed as $\vec{TA} \wedge \vec{HT}$. It is stored in an attribute named normal, to be used to rotate the Bezier curves handles.
Build and adjust flightpaths

1. .
2. .
3. .
Resources

Hi! First of all thank you for your extensive response @StefLAncien
!

I made a new file, where i didnt apply so many subdivisions on the sphere (I know the sphere isnt a perfect sphere on top, but ill figure that out another moment).
.
Your image looks good, thats what I want. My real file will consist of many, many more points on the otherairports data, so thats why geonodes setup is neccesary.
I tried a setup in the file above but I just cannot figure out how to

I deleted a comment with a follow up question, as it seems a separate question instead of relevant to this thread ;)
Thanks again! Many respect!


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Rectangular to cylindrical coordinates with volume material
I'm trying to create a volume material which consists of several rings that pulse outwards. I have a solution with a cylinder. It consists of a wave texture of rings along the x axis, where the phase is driven by frame time.

I'd like to wrap this in a torus shape. I have tried using rectangular coordinates to polar coordinates as an input for the vector of the wave texture, but can't seem to get cylinder wrapped in torus.

I think we need to take into account the torus major radius to do that.

The idea is to take a slice of the torus and calculate wave input coordinates from the slice center point.

Which can be done with the following:

Get X Y component to have the axis to the center point.
Normalize it and scale by the major radius of the torus to obtain the slice center point.
Use two dot products to have X along Z and Y along the axis to the center point.
Use the wave and use Z axis for it as we calculated X, Y above.

Awesome. I didn't think about using the vector scale and subtracting it from the original object coords to make a new coordinate system. In my head, the second coord system is X pointing out in the direction of the major radius, then y pointing up, and z pointing along the curve of the torus. Thank you! Now I can stretch gradient textures into toruses as well! And scale the x and y components!
I do see cylindrical coordinates here... I see a r, theta, z. I'll see if a similar result can be done using arctan rather than vectors. Thanks very much!

A possible approach would be to use distance-from-circle, Pythagoras all the way.
This group returns the 3D distance from an XY circle of radius radius centered on 0 in your given vector-space:

The distance-function, if put through a less-than threshold, yields a volumetric torus. It could be used pretty much the same way as your distance-from-line.
Here with some bells and whistles, Ping-Pong-ing the distance to give bands in the torus volume, varying the colour with distance, offsetting 0 to animate the bands:

for this kind of result:

Ooops, probably backwards, for you.. reverse keyframes in the 'Add' node...


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By using proportional editing, vertices are moved in the wrong axis
So I am following Andrew Price's 2.8 Donut tutorial but sometimes (not always) when I move vertices with Proportional editing, it moves the vertices around it really unpredictably (see screenshots below).
I don't know how to make it all move adjacent to the camera rather than bits shooting off that I didn't even grab directly in the first place.
Is there any way I can do this?
---Screenshots---
Before:

Grabbing with PE (looks fine):

After:

Have you applied scale to the object? Object>Apply>Scale. Did you use "Connected" in proportional editing? Also have you checked that X-mirror is not enabled in options?


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Rotating bone of rig created using automatic weights moves other areas of mesh
I have a similar problem as this question. I'm trying to learn blender, and am attempting to rig a low poly dog model, but when I rotate one of the legs in pose mode, the opposite side leg follows, but I can't figure out why. I made my rig the parent of my mesh by first selecting my mesh object, then my armature, hotkey Ctrl+P and selecting “With Automatic Weight”.  Per the answer to the similar question I mentioned, I followed all the advice there (applying scale and rotation, fixing normals, etc.). The mirror modifier I used to create the mesh has been applied. There is a subdivision modifier and a decimate modifier both on the object (not yet applied), but neither applying nor removing those fixes it. I've moved the armature modifier to the top also, but that doesn't solve it either. In every tutorial I find, it seems they are able to use "With Automatic Weights" with no problems -- what am I missing?
Here is my blend file:

Try editing the weights, so each bone only affects the part its supposed to.

As you can see, you have flipped normals, recalculate them. Also, apply the scale and rotation of both the object and armature. Then reparent the mesh to the armature.

After recalculating normals, I also had to sever the relationship between the armature and mesh and reparent it and it finally works. Thank you!

sure I forgot to say to reparent  ;)


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Blender Won't Render Transparent Images Properly
So I'm new to blender, only been using it for a week. I've looked up a lot of tutorials and I'm trying to figure out how to make animations with it. Currently I have something set up like this:

The materials and texture have alpha turned on, and I went to render. I tried looking at it through F12 but this is what comes up:
Update: Turns out the light was making shadows, so I turned it off, but I still end up with this:

There should be several tutorials on Youtube, or I can get back to you if you're stuck.  Just leave a comment here.

Added to the above - Have you tried rendering with OpenGL?  It's way faster and what you see in the 3D window (viewport) is what will be rendered to video.

Well, I have tried youtube but none of them work. And I tried to get OpenGL but I can't seem to find a download link to it.

When your project is loaded, go to the left of the top of window.  Click on the "Render" option, then the OpenGL Render Animation.  That will use your hardware to render to video, what you see in your 3D window.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Object won't render over tracked background image
I've been working on an animation trying to incorporate animation into the background images.I don't know the reason why it won't render the arm. I  tracked and solved the motion in the movie clip editor, and here's how it renders:

I'm using blender render and not cycles.Items that I figured probably aren't as important are blurred out a little, so it's easier to see what settings I have.
If anyone can help please do. Here are some settings of that part of the arm that shows up in the render as transparent:

Thanks!
-CHorse

Possible duplicate of Why does my object not show up?

Also see https://blender.stackexchange.com/questions/53632/render-result-is-completely-blank/

Well the problem is I don't know if you guys saw but it's in blender render. I didn't use any nodes, and I don't intend to switch to cycles because blender render worked fine for my other animation, I don't know why it's acting up now.

Well in the movie clip editor it has something that solves for the camera path.
and as for links; I checked them out but it didn't help because I either had the setting active or it was for cycles, which didn't work out because I'm on blender render. What's the compositor?

why don't you have any texture file loaded in you texture settings?

@cegaton I put it up

Possible duplicate of Transparent rendered object over tracked background


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My cloth simulation is going through my face model no matter what I try

I have a problem regarding my cloth simulation. I am working with a mesh of a face that I want to put under a cloth and see its lips move under the cloth. However, no matter the parameters I tweak, the cloth keeps going through the mesh. The main improvement in my tweaks was disabling the "Single sided" option in the collision object (face mesh). Increasing the quality of the simulation and the collisions didn't change anything, so I kept it low enough to be able to run the simulation easily.
Here are my inspirations regarding the project I want to make:
https://youtu.be/G1VBbHowAs8?si=MUI3eM1VRxx410D4
https://youtu.be/OguGDqf9xgs?si=UqKRAbVXyxhIHzsZ
I haven't found an answer on any question asked before, so I hope you will be able to help me on this. Thank you very much !
(I couldn't get the .blend file so it's in the .zip)

Hi. I've added a screenshot to your question. Cool effect. With the wireframe overlay+X-ray you can see better what's going on. The mesh faces are stretched as the face object pushes against it. The reason why it pushes through the cloth mesh at some point is because there is not enough geometry left to calculate the collision properly. For the same reason you can not see the shape of the lips when the mouth opens. Maybe try to fake the desired effect with a 2nd cloth simulation+a 2nd mesh at a certain frame.


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Creating Clothes using the Mask Method
I was trying to create clothes for my female character but when I create a mask and extract it, parts of the torso do not get extracted properly and some parts get joined to the neck.
Here is how it looks. In sculpt mode, I used Mask Brush to paint the area to be clothed and went to the mask options from the top menu and chose Mask Extract. Then unchecked Extract As Solid and extracted the mask.
But some parts of the torso did not get extracted with the mask and some parts of the mask extraction joined to the neck.

Have you checked if the face orientation is correct? Have you applied the scale to the model? (A negative scale can flip normals). Make sure that it's not parented to a rig or something. Had you left the Project to Sculpt option enabled? (it's by default). This seems to work like the shrinkwrap modifier. I've tried it on my own model which was parented to a rig and still scaled up. With this option enabled the result was that the shirt got crumbled on the head. Without this option, the shirt was ok but scaled up.

Yes it's parented to a rig

Thanks a lllooooooooottttttt, It worked!!!!!

Cheers! :-) So the rig and this Project to Sculpt option caused the problem? Feel free to post an answer to your question.

I don't know about Project To Sculpt Option, but it was the rig being parented to the mesh caused the problem, I deleted the rig and now everything is solved


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(FIXED) Blender 3.2.2 Desired material wouldn't apply, emission color shows up instead
I tried giving this svg a metallic texture, i selected the svg and put metallic at 1.000, roughness at 0, switched the viewport shading to material preview and also tried the rendered preview it still wouldn’t show up as metallic and only showed the emission color, then i redid everything and switched to edit mode and selected everything with A then applied the material, still didn’t work. i’m sort of new to blender so i’m really sorry if i overlooked anything even though i feel like i’ve done everything by the book but still didn’t get the desired results, any help would be extremely appreciated.

metallic 1.000 , roughness 0.000 , emission strength 1.000

metallic 1.000 , roughness 0.000 , emission strength 1.000 (red)

metallic 0.000 , roughness 0.300 , emission strength 1.000

metallic 1.000 , roughness 0.000 , emission strength 0.000
[FIXED!!]
after contemplating abandoning the project i tried one last thing which was to uninstall blender(3.2.2) and re-install a previous version of blender(2.80.75) which worked!
get the msi file of either x64 or x32 windows depending on your system:
https://download.blender.org/release/Blender2.80/
list of all the releases if someone wants to experiment further or attempt to find the most recent version that doesn't have the material problem:
https://download.blender.org/release/

hello could you please share your file? https://blend-exchange.com/

of course @moonboots ! although blend-exchange wouldn't allow it, i've put it up on we transfer https://we.tl/t-ZjFiWmgwhT

It works fine in Material preview, in Rendered preview you need to reactivate Scene Lights and Scene World, it won't work fine because you don't have any HDRI image for the world for the moment. But it doesn't look black like in your first picture

i've added an HDRI and tried to apply the material to a sphere to see if the svg is the problem but they're both black, i'm guessing it has to be a hardware issue, thank you for checking though i really appreciate it @moonboots!

yes it may be a graphic card or driver issue? I hope someone will know...

@moonboots i fixed it somehow through installing a previous version of blender so it's confirmed that it has to be drivers or graphics card either way now it works, thanks again!

Oh ok i hope you'll find a solution

what does it give if you switch to a previous driver version? there are some problems with the last AMD driver. Also maybe try in the Render panel > Performance > High Quality Normals


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Emulating a rifled scaled extrusion: create rim faces between levels
A note on what I would like to end up with:
The effect I want to finish with is a kind of rifled, scaled extrusion. But I would like to maximise end-effect editability. The screw modifier represents the basis of what I need, however, at every 'level' I would like to maintain control over the lattice's simple deform bending, rotation, and  scale.
What I've got: My thinking at the moment:
So, taking a look at the images I've attached; I've taken the individual plane and duplicated it to several z-altitudes, scaling and rotating each time. Each duplicate has a simple deform modifier associated with it.
What I would like to do now is emulate the effect of the screw modifier, joining each level to create rim faces.
All suggestions and questions welcome!

So you want a screw-like "tower" with this profile getting smaller towards the top? Are the colors in any way relevant or just to see it better? But I guess you don't want something like this: profile screw because it looks like your profiles are curved somehow...


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Radius-Variable Screwing, possibly involving nodes
a novice here looking to be ambitious (and presently failing).
I'm trying to take a polygon plane (approximately circular and with radius = R) and screw modifier it with an R that reduces in size with z-position, such as described in the attached media, such that the eventual screw mimics a circle.

Given that a similar solution is presented in method 2 here, I suspect the solution will involve either Geometry or Animation nodes, but as a 3D modelling novice, I have absolutely no idea how to do nodes, and I'm not even sure that Blender can do what I'm asking. I also suspect that a python script would be involved.
Advice, pointers, suggestions, and demonstrations from the advanced blender community would be greatly, greatly appreciated. Even links to appropriate nodes & python youtube tutorials would be great - my problem as a novice is in part not knowing what to search for...

Hi, welcome to BSE! We're a welcoming community, however we're driven by a very specific ruleset: Tour. Please make the title of the question specific, e.g. "Use a screw modifier on a circle to get a sphere", also please put some effort into the question: a scan of a sketch is absolutely fine, but you should write down the description in a text form that will be searchable. Also show what you have tried already as a proof of doing your homework, cheers!

... or is this the sort of thing?

A screw modifier is probably not the way to go, or perhaps I don't understand your question... The question linked by you indeed produces a screw. The sketch you provide doesn't resemble a screw.
So let me try to take advantage of Cunningham's Law and post a first answer:

I guess that OP may wish to rotate each plane to form the screw, something like this?

So a node layout something like this?


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Is there a way to limit a node input field's range?
this isn't necessary, but would definitely help save time & frustration for housekeeping/troubleshooting on my procedural materials.
I'd like to be able to put a limiter on a node input field so that it would functionally stop at specific minimum and maximum positions--not unlike many existing node fields such as texture detail: 0,15; or generative texture Randomness: 0,1.
While I use a Map Range node to functionally remap this range , I'd like to, in addition, prevent the actual value field from being manipulated beyond the remapped range when click-dragging across the input. Can I limit a MR node value field or a Value node value field (or any other node field for that matter)?
Does anyone know of a (preferably low-cost) way of doing this?

Taiyo's way is probably the best, especially under the "low-cost" request. Other alternatives than already mentioned Map Range: Math minimum and maximum, ColorRamp, Float Curve and similar nodes.

Thank you, @Markus von Broady! Taiyo's way is the answer. The other alternatives will limit the signal, but they're not what I was looking for: I wanted a way to limit the value itself, rather than the resulting math. I could better describe it as a potentiometer (or electric knob if I'm using the term incorrectly): some will come to a hard stop when you turn them to their maximums and minimums and some will turn infinitely past the limits. Both will limit a signal that they send, but one of them gives you feedback to "feel" the limit and that's what I was nitpicking. Cheers!

This is why I listed a float curve and a colorramp, where the interface also has a limit, though for the latter it can't be changed.

Ah! I'm not familiar with the float curve node, but I use a lot of Color Ramp nodes as limiters, though I find them awkward and finicky, (in this case I was actually using the Value node -> Mapping -> Math multiplier to fine tune a Color Ramp that manipulated a Gradient Texture). Too many Color Ramps in one NG is surprisingly hard on my concentration and focus & I prefer the feedback of the number value being prominent in the field. Thanks for the clarification, I will check out the float curve!

anyone know how to do it for geometry nodes? https://snipboard.io/dG5nia.jpg

You can utilize Node Groups for that (dont know if there is a shorter way). In a node group you have control over the input and output values. Create some node, right-click it and select Make Group. Now within this group node you can put constraints on the input and output values with Default, Min, Max (you can also rename the fields and group, manage the in/outputs and so on). If you dont need the actual node with which you created the node group, you can remove it, so you are just left with an "empty" node group.
If you dont find the node menu, its hidden behind the (very) small < in the top right corner of the shader editor. Additionally, to leave the node group again, click the upward arrow icon. In the screenshot, the input field MyValue of the node group NodeGroup behaves now like you want.

This is the answer! It's too bad that we can't do the same to nodes themselves, but that might also become a housekeeping nightmare.

Oops, I accidentally entered the comment before finishing: Thank you! With your advice I put everything into a Node Group, removed the Value node and used a NG Input with limits to noodle a Mapping node that remapped the 0,5 range value to what was needed for my multiplier (Math) node. To add to your reply for others: 'N' will toggle the popup menu on the right and there should be labelled tabs along the right side that can be clicked for the appropriate context ("Node" in this case)

this doesn't work for geometry nodes https://snipboard.io/dG5nia.jpg

@HarryMcKenzie the setup in your image works for me in Blender 4.0. Maybe a Blender 3.x version bug? Edit: works only when clicking on the arrows, not when typing a value directly into it.

@taiyo should i file a bug report or do you think there is already a ticket for this?

i also noticed it will not work for the increment/decrement button if you set minimum dynamically like bpy.data.node_groups["mynodegrp"].interface.items_tree[2].min_value=value or inputs[1].min_value = value (those paths are from copy full datapath). it only works if you manually input the min_value and press enter. no other way.

@HarryMcKenzie i am not aware of a report, but this may be dismissed anyway. The docs https://docs.blender.org/manual/en/latest/interface/controls/nodes/groups.html say: "The minimum and maximum value for the UI button shown in the node interface. Note, this is not a minimum or maximum for the data that can pass through the node. If a socket passes a higher value than the maximum, it will still pass into the node unchanged." So i guess, inputting the value directly or with code is considered valid bypassing.


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Unnatural shadows in corners with Cycles
The problem is that in all my renders the shadows in the corners, where objects/surfaces touch each other, look unnatural. The objects look "floating" above the surface, or "detached", like I cut them from a different picture and photoshopped. It feels like there is no ambient occlusion, if I'm not mistaken. Can you advice how can I improve it?
I use Cycles and Principled BSDF for all materials. The only light source is HDRI. Normals look correct - all faces are blue. The render settings are:

Here is the render:

The shelves look "floating":

The cabinets and floor also look unnatural:

Although some objects look not bad. For example, the plant or cabinets and ceiling:

200 samples with denoising can be really asking for troubles. The less time you spend rendering, the more the denoiser has to invent and approximate what should be there. I might be wrong on this, but that could be the source of your weird shadows. Plus, depending on your HDR, lighting can be weird anyway.

Render settings look fine, the shadow of the cabinet matches with the one on the plant. I think it looks overall weird because the chosen light setup doesn't valorize the scene. It's an artistic issue, not a technical one. Try to rotate the hdri, or use a different one, find some references that suite your project ant try to match them... ecc

Thanks for the input. I will try to play with HDR and do more samples.


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Using external (Snow/Rain) Rigs on own characters
I want to animate my own characters using the Snow or Rain Rig provided by Blender. Are those Rigs bound to the Snow and Rain Characters, or can I use them for my own characters?
If it's not possible, does anyone know how to use external rigs on own characters without building everything from scratch?

where is a snow/rain rig?

These are from the Blender Studio

Before the technicalities, you have to consider the legalities. Can you legally reuse a rig (or anything) that isn't yours?
Most laws consider that you cannot do this unless the rights holders explicitly state otherwise. Which means you have to check every time.
In your specific case, Rain and Snow are both published under CC BY 4.0, so you could use them with conditions.

For the technicalities: in general, you can't really re-use a rig made for another character. Unless that character is exactly the same proportions, and same deformation features, it will be a lot of unnecessary work to make them "fit".
That being said, lots of rigs are not made from scratch, but instead generated with addons. Rain and Snow are made using Cloudrig, which is a custom Rigify set.
So if you want to generate a rig like these, you just have to download and install Cloudrig into your Rigify and use it. It's all explained in Cloudrig's documentation. Then it's basically like generating any Rigify rig.


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Use shader's texture in displacement modifier
Is this possible?
In my shader in cycles, I have a noise texture hooked up to a displacement node.
In Eevee, I would use displacements by using the displacement modifier. There, it lets me select a texture image.
If I could just somehow export the noise texture from the cycles shader as a texture usable for the displacement modifier, I'm golden.
Is this possible?

I don't have experience with that, but I think the solution to this would be to bake it

@TheKalaakaar I figured it out and I'll never go back to using these premade texture nodes, now I can edit them in gimp

As of today, you can't exactly use shader's textures into modifiers. You can either recreate your texture in Blender's legacy texture system, or bake the texture into an image.
The legacy textures system is limited and clunky, but it remains faster for simple setups and procedural. While baking requires to create and load external data that you can't change.
Legacy Textures
From your displace modifier, you can hit this button to open the texture's settiongs in the legacy texture tab of the Properties Editor:

From there, you can change the type to a different procedural noise:

You could also have more control making a procedural texture using nodes via the legacy Texture Node Editor (shortcut: ⇧ ShiftF3), but it's been abandoned for years now and seems broken in v3.6.0:

Bake the texture
Open the Image Editor (⇧ ShiftF10) and click the New button to create a new texture. Give it a name, disable Alpha as we won't need it, and click ok.
In the shader editor (⇧ ShiftF3), plug the last noodle of your texture to the Material Ouput's Surface socket, or ⎈ Ctrl LMB the last texture node to do the same if you have the Node Wrangler addon enabled.
Add an Image Texture node with the texture you just created, and make sure it is selected.
It should look like this:

In the Properties Editor > Render settings, switch the render engine to Cycles (only it can do baking).
In the Baking panel, set the Baking Type to Emit (it will be faster to bake).
Make sure you have a big enough margin depending your texture and UVs. And hit Bake. It should take only a few seconds.
In the Image Editor, you should see your texture. From there, hit ⎇ AltS and Save your texture into a file. If you don't, Blender will discard it when you close the project.
Back in the legacy Texture tab of the Properties Editor, set your texture file in the texture (if you don't see the option, just create a new texture).
Then set your displacement Strength to a low value, like 0.1;
As for the texture's nodes from your shader, you can either remove them, or unplug them and leave them here to be able to change and bake the texture again if needed.

Don't forget that geometry nodes has all the textures as well as a fair amount of other shader nodes available, and it's pretty trivial (around 6 nodes I think) to construct a displacement modifier equivalent that can be driven by a tree of such nodes. Better than baking since it allows a rapid iterative workflow and I use it for anything not inordinately complicated.

Feel free to post an answer for that method. I barely ever use geo nodes so I can't talk much about it.

Did this by following this tutorial (https://www.youtube.com/watch?v=LLQFopN--LY):

creating a image texture node
creating a new image in image editor
setting the image texture node's image to the new image
with node wrangler, ctrl shift click the noise texture node so that its output is displayed (or just hook it up to the material output)
bake with type "combined"


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why when i edit bones and open mirror funtion,the other side move weird
here is the video
I guess it is relative to bones'axis .i don't know.
and when i rotate both the character and the bones,thecharater's left arm distort.

here is the video

The mirror is mirroring on the X axis, so your model is supposed to face to the Y axis. But your model is facing to the X axis.

@FFeller must be a mind reader?  ;-)

sry i don't know how to upload a video .i use rigyfy .when i change the character facing to y axcis .it' still not working

You have to do it in edit mode, or apply the rotation if you do it in object mode (ctrl+a).


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My viewport movement is inverted and strange
I'm not sure what I did but when I rotate my view in the viewport, it's like it's inverted or rotating around another object offset from the one I've selected. Any ideas as to what I did to cause this?

You may have enabled the option called "Lock to 3D cursor", which can be found by pressing 'n' to get the side bar and clicking on the "view" tab.

Hello :). Nice Q and A. If you find the time, you can also add some images to better illustrate the answer.


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Method of creating verticies around object in photo based on background color
Similar to how you would select the outline of an object based on a common background color in a 2d graphics program and then delete the background, is there a way in Blender to import a reference photo and create vertices automatically based on where the object in an image meets the background color. For example, making the vertices that would create the outline of the lettuce leaf in the image below:

What about using a vector program to trace it then import svg curves into blender?

+brandon-bien Thanks, that actually works better than I expected. I can even use GIMP to do an auto select, make that selection a path, then export it as SVG and import into Blender pretty quickly.

Glad that helped, don't forget that inkscape has a trace bitmap function under path that will do a simliar thing.


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Can you turn off object visibility in a separate window?
Just for the sake of modeling something, I wanted to have two Blender windows, each on separate monitors and have one show the model and empty references images and the other to only show the model. Is this possible?
Right now I have the two windows, and both showing the model and reference photo empties, but of course if I use the outliner to control viewport visibility of an object, it does so for both windows. I seem to remember that there was a way to make viewports independent, but maybe that was an older version of Blender.

One way to do this is to take advantage of local view.

Set up your second 3DViewport exactly like your first and move it to your second monitor.
In that viewport select only the items you want to have visible.
Type / to enter Local View

Everything except the selected objects will seem to disappear.
The / key is a toggle, so you can switch between local and global view.  But if you switch back to global view remember that the next time you switch to Local view only the things you have selected at that moment will appear.

That's a useful method too. Thanks.

Because it is an empty that you want to hide, one convenient way of hiding only those in a single viewport is to deselect empty from the new Object Types Visibility menu at the top right of the 3D viewport as show in the screenshot below.

In the screenshot below it shows a split viewport where the top one has two image reference empties that are visible and in the bottom one it has the same cube object visible, but without the image reference empties.


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Camera keep changing object
Something weird is happening and I don't know why.
I imported an animated .fbx character from Maximo. Everything seems fine but whenever I try to move the position of the camera the character seems so stretch as if it is attached to the camera.
I tried to delete the camera but I keeps happening. Does anyone know how to fix this?

Kind of Dali effect? Could you upload your file using https://blend-exchange.giantcowfilms.com/ ?

It's probably parented to the mesh, click on the camera and hold down Alt+P. And clear the parent.


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Is it possible to see or edit several frames at the same time in viewports?
First of all, sorry for the title of the question but I don't really know how to phrase the all thing.
Here it is :
Okay so let's say that, on frame 1, I have a vertical bar.

What I wanna do is for that bar to be at a 45° angle on frame 30 but with no keyframe.
So I naturally go to frame 60, put the bar at a 90° angle to make the bar rotate half-90° at half-60 frames.
Is it clear ?

My ultimate goal is to have tens of elements going from their point A to their point C while only being interested in their point B, somewhere between the two, where all the elements would harmonize in a bigger picture.

The issue is that I would like to play with several factors like location and X, Y, Z rotation at the same time and won't have easy values like "90÷2" most of the time.
So rather that doing complicated maths for each factor of each element to determinate their A and C points, I was wondering if there was a way for Blender to display the viewport at three different times in three separate windows.
It would allow me to live-tweak point A and point C to adjust point B.

Hoping that I'm being clear, can someone help me ?
Thanks a lot.


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Spherical Arrays in Blender 2.8
I am trying to create a spherical array in blender 2.8. (I am trying to make a liposome form two opposing lipids) I understand that in the previous blender versions I would have taken my object (here the lipid) and added a sphere. Then I would have used the "dupliface" function to make the array form the faces of the sphere. In Blender 2.8, this function is gone.
Can anyone help me? I greatly appreciate it!!

could you please show a picture of your final goal?

Try in the Object properties panel under 'Instancing', that seems to work as expected.

Thanks, this works


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Face rig shapes keys
Face rig shapes keys are not working in right direction but only working in left direction.

Why is this happening?

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


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Help with Shading for a pencil model
I'm currently working on a tutorial for modeling and shading a pencil, and I'm trying to make the shading good enough to create those distinct markings made on it by sharpening it.
Here's where I am in the tutorial...
https://youtu.be/OaB92KsvOtM?t=255
Here are some images I'm talking about...

And here is a link to the downloadable file of the project I'm working on...

Updated model:

Yes, the updated model looks much better :-)

Compared to the tutorial your shader nodes differ slightly. That's the reason why it looks different. But it's easy to fix.
Shader adjustments

increase the Scale of the Voronoi Texture to 50
remove the 3 duplicated Color Ramp nodes on the first one. There are a bunch of them stacked on top of each other.
set the Fac of the MixRGB (Multiply) node to 1 and adjust the color a little bit, less saturated (S) and higher brightness (V), something like EEC176 (HEX).
make the first color of the first Color Ramp a grey value like E5E5E5.
increase the first slider of the second Color Ramp to the middle as shown a bit later in the video.

Mesh adjustments
Switch to Edit mode, select everything and remove the duplicated vertices with M > Merge by Distance. Repeat this for the other pencil.
Optional adjustments
Scale the pencils down to real-world size and apply the Scale in Object mode with Ctrl+A > Scale. This way you can easily append the pencils to other scenes and you don't run into issues with the lighting.
You also can add a Bevel modifier, to make the end of the pencil look more natural and not that sharp-edged.
In Eevee render settings, turn on Ambient Occlusion and Screen Space Reflection. Last but not least, set up an HDRI in the world shader settings like Cayley Interior and the pencils will look like this:

I don't see these extra color ramps anywhere for the shader. What do I do?

Which extra color ramps do you mean? There are just two color ramp nodes as shown on the screenshots and the video...

What is the real world size for a pencil when thinking in Blender?

Does this look like an improvement?

Does this look like an improvement? What do I do next?

Blender's measurement unit is 'meter' by default. You can check the dimensions of an object in the side panel ("N-panel", key N to open it). Your pencil is about 8 meters tall. A common pencil is about 16-18 cm long and 7-8 mm thick. So you need to scale it down by a factor of 0.021. Size comparison => https://i.sstatic.net/tl7Lh.jpg -- Yes, it looks like an improvement!

Do you think the marks on the pencil look good, or does it need to be improved a bit more?

Should I be worried if the model I'm working on doesn't look EXACTLY like the one in the tutorial?

Shouldn't the exposed parts of the wood have lines going down them?

It looks fine to me. But it depends on what are you going for. If you want to have it super-realistic in a closeup render then you might want to tweak it a bit more. If you want to use it for animation (holding it in the hand, writing a letter, or so) it's totally fine. You don't be worried if it doesn't look exactly like in the tutorial. It's your pencil. It's fine when you like it ;-) The difference is the scale of 0.1 by the way. And for critique is better to ask here: https://blenderartists.org/c/artwork/focused-critiques/ since this here is question and answer site, not a forum.


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Where can I change the color of the vertical tab labels in Blender?
Where can I change the color of the vertical tab labels of the N-panel in Blender? (red marked square)

You can't unless you mess with the source code.

These vertical Tabs are adjusted per editor.
For 3D Viewport, it's in Properties > Themes > 3D Viewport > Theme Space

Go to Properties > Themes > 3D Viewport > Theme Space > Region Text.

If you like your settings, you can copy them via the eyedropper (in theme preferences), for instance, from the 3D Viewport to the Node Editor.

If you want to delete your answer, please do so through the "Delete" option rather than removing the content with an edit


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Hair Geometry Nodes not visible / does not render
I would like to create a hair geometry node setup with procedural distribution.
I got it to work with an image density mask (top left) where I got those nice stripes. I want to do the same with a wave texture procedurally and the curves appear in the right place, however I found no way to apply a thickness/geometry to the hair, so it won't render.
Do you have any ideas for this?

Update:
Here are two screenshots with the Set Curve Profile node (not rendering):

And Curve To Mesh Node (does render):

What do you mean by "I found no way to apply a thickness/geometry to the hair, so it won't render."? The (hair) curves of the Curves object are rendered natively by Eevee and Cycles and do not need geometry (=faces). Set the curve radius with a Set Curve Radius node to control the thickness of the curves. There is also a Set Hair Curve Profile node group in the Add Node menu (Hair > Write > ...) with more options. -- If you want to export them you need to convert the curves into a mesh with a Curve To Mesh node. This will create geometry with faces.

Thanks for your comment! I tried this and it still won't render for some reason. If I add a Curve to Mesh node, it will show, but then I have all the geometry that i did not want. If I just add the Set Curve Radius node, it just won't change show up.

Thanks for the new screenshots. I've added them to your question.  This is a Q&A site and works differently than a forum. If you post them in the answer section the post will be removed because it's actually not a real answer but a follow-up info. It should be added as an edit in order to keep the page structure clean (one question, multiple answers).

Have a look at the Set Curve Radius and Curve to Mesh nodes that you have added. They have a little "[i]" icon at the top right corner. That's an error message. Hover the mouse cursor over it to see the message. My guess is that the Geometry input in your node tree not only contains curve data but also mesh data. This causes problems. You either need to make sure you only have curve data -or- you need to split the data types. If you tab into the Generate Hair Curves node group you will see a Separate Components and a Join Geometry node and the group only handles the curves.

Hair curves renders as hair curves only in hair object:

If you make hair curves on object itself, curves will be interpreted as usual curves, that (if they have not converted to mesh) is not rendered.
So the problem is how to transfer data from mesh to hair object, I suppose. This can be done using sample nearest surface point node:


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Help with animation. Simulation ends prematurely. How to extend it?
I'm currently working on a video featuring soft-body sphere "blobs", and I want to make the animation longer so I can see what's going on, but despite me extending the number of frames, the animation stops around frame 240. How do I make the animation last as long as I want to?

In the Physics panel, under Cache, you need to increase the Simulation End value for each ball. If you want to change for all the balls at once, select them all, change the value and Alt Enter.


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I want to have cold smoke emitting from bottle but can't get the settings right
So I want to make an ad video for my portfolio. It's a beverage bottle and I saw a tutorial on Youtube which was smoke from a cup of tea. It worked for the top part of the bottle and I tried to tweak it to have smoke kind of emitting from the bottle itself. But it didn't work.
It was this tutorial: "How to Create Steam w/ Mantaflow" by Blender Made Easy
I want the smoke to emit like this:

With current settings, the smoke emits out of the bottle but it's too much smoke. It's like it's on fire, while I want it to emit lower smoke so it seems like it's cold.
Also, let me know if those settings could be further optimized in any way.
Thank you.

I think what you want to create is physically fog, not smoke. It's cold condensed water in the air that settles down and in this case, dissolves quickly.
To simulate cold gas there are these settings in the domain:

Buoyancy Density - values below 0 will cause smoke to sink.
→ Give it a try and set this to -1.0
Heat - controls how much smoke is affected by temperature. Values below 0 will result in the opposite of positive values, i.e. smoke emitted from flow objects with a positive Initial Temperature will sink, and smoke from flow objects with a negative Initial Temperature will rise. → make this also negative, -1.5
Vorticity - can add a bit turbulence, try 0.1
Dissolve > Time - if you lower this value the smoke will disappear faster. But you also can lower or even deactivate the Wind Force Field to keep the smoke closer to the bottle.

The bottle (gas inflow) has the

Initial Temperature. It's the difference between the temperature of emitted smoke and the domain’s ambient temperature.
→ Keep it positive. You can experiment with it. I've increased it from 1.2 to 2.0.

Test with the adjustments (frame 168, Cycles):

With a shorter Dissolve > Time value of 10 frames:

In the Shader you can adjust the values for the Multiplier nodes and the ColorRamp to control the visual appearance ("strength"/density) of the fog. I've lowered the values a bit, adjusted the values of the ColorRamp and set it to B-Spline:

If you want to animate the condensate droplets this question might be helpful:
How to animate metaballs as condesate drops

Thanks A lot man, never thought with this little tweaking it could be perfected, also that metaball drops is really dope, that should be on youtube tbh, But I have one question on Heat, as you mentioned "with positive values it will sink and with negative values it will rise" and we want our smoke to sink in this case then why did we used negative value ?


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Remove every nth Vertex with Geometry Nodes/Python
Node noob calling all node gurus.
I'm working with some simulated galaxy data at university and as an aside, I'm wondering if I can render it in Blender - however because it was legitimately simulated on a supercomputer there are a lot of data points. I've already cropped the data but I need to 'sparse out' the render by removing every nth point. I would like to do this non-destructively using nodes, but will fall back to python if that falls through.

Also, for some reason, my point-radius allocation isn't working.
Cheers!
Part II of the project is here.

Hello ! You might want to explore the point cloud visualizer addon which is awesome to visualize point cloud data. It is paid for though. https://blendermarket.com/products/pcv The Set Point Radius node isn't working because it expects a Point Cloud native geometry type, and you seem to be using a mesh with vertices acting as a point cloud (not the same, and not optimized for extremely large number of items). What is the format of your input data ?

or you may remove randomly points.

"I would like to do this non-destructively using nodes" - why? This way the process will consume resources on each frame.

Are you working with vertices-data only? This setup would remove every nth vertices of a mesh.
EDIT: I have modified the setup based on user recommendations

Hi Robert! That works great in edit mode, but when I switch back to object mode all the original points become visible again. Any ideas?

Why "Truncate"? Also it doesn't remove ever nth point, it keeps every nth point.

Yup you can use an integer output in geometry nodes instead of the value + truncate nodes. And add a boolean invert between the modulo and the delete geometry node

@Blenderman Sorry, I have no idea why that happens. Could depend on your input data/mesh or other things. I tried a couple of primitives with this node setup and I did not have this problem.

@Gorgious You are right, I have modified my answer accordingly. Sorry, I'm new to Geometry Nodes.

One reason why maybe this doesn't work is that it uses ID node. If ID doesn't exist, it uses index, but if it does, it could as well be all zeroes. BTW, instead of using "NOT", perhaps a more readable (but maybe slower, I don't know) compare node could be used: personally, I would use "equal" in integer mode, to signal I'm expecting an integer as input, and compare with 0 explicitly, rather than rely on float to boolean conversion, which perhaps not everyone understands (0 is False, otherwise True). I admit though, there is something satisfying about converting values to boolean.


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Maelstrom Profile
A node-noob calling all node-geniuses!
This is what I'm after:

However, at present, points are only being generated on the curve profile of the object specified below. These points are then being converted to a volume and then a mesh. What I need is for points to be generated inside that curve profile too, such that I end up with a solid volume.

This is a partial snippet of my node layout, and is - I suspect, where the problem lies. The full layout is available in the linked [project file] here.

Update 1

I've tried modifying the nodes, replacing [distribute points on faces] with [distribute points in volume] but the model vanishes.

...and as helper for no money helping in our free time without getting anything for it - you should provide a blend file to make as easy as possible for us to help you.

You're right, I've provided a link in the desc now (y)

The distribute points in volume node should do exactly that

Sounds like it should do the trick. Tried it out and I've gotten something in error. Could you take a look at the update and help me out on why my model's disappeared?

fist of all, what are you trying to generate as the outcome, because if you share that piece of information we can give you a better answer. Second of all, can you share what the error on the distribute points in volume days, that could be the solution. Last of all, try filling caps on the curves to mesh.

Hi Shmuel, I've added an update. Please let me know if this helps and if a 'desired outcome diagram' is something you wish were 'standard submission' in these forums.
Re. second point, there isn't an error as such: the model just disappears, as shown in photo-4.
Re. point 3, perhaps there is a way I could do so procedurally, but I would appreciate an example blend file on how exactly to do that. If it isn't procedural, then I resist using this as an option.

In the node Curve to Mesh enable Fill Caps, then use Mesh to Volume and after that you can use Distribute Points in Volume.

@Quellenform you absolute beauty.

ANSWER RE @QUELLENFORM 19.04.2023:
"In the node Curve to Mesh enable Fill Caps, then use Mesh to Volume and after that you can use Distribute Points in Volume."

^ Working node configuration.


text:
Create a sphere mesh, subtracted of a load of points using Geometry Nodes
Calling all nodes geniuses.
I'm trying to subtract a load of points from a UV sphere of radius $R$. I'm seeking the end effect of something that looks like a planet cracked in two.

Please note I'm quite new to nodes, so small words plz and plenty of pictures
Cheers!
ps.1 My next stage of the project is to create a variable number of random length lines $L$ that shoot radially out from the centre of this same model. These lines begin at radius $R_0, R_0>R$. I know blender doesn't work on spherical coords $(r,\theta,\phi)$ but these lines are to have random $\theta$ and $\phi$. If any node guru wants to take home fifty points for Gryffindoor, advice on how I could achieve that would be - and I can't stress this enough - mega.
ps.2 I'm aware my screenshots aren't the best resolution for the total map, so I've attached a link to the blender file here should you want a closer look.

You have not defined what r, R, L, δL, θ and ϕ are.  It's probably possible to guess what those are, but why would you want to make people guess the problem before solving it? Why not define it exactly without uncertain terms? You should draw a diagram showing what they are so it is exact and clear.

You should ask it as a separate question, but you could distribute random points on faces of a sphere and the use those points to instance lines, taking the rotation of the points for instance rotation so they end up rotated in the direction of sphere face normals(so that's approximately as if the lines were going from the center of the sphere) https://i.imgur.com/wNrqGtx.png You could modify the sphere geometry if you need to limit where the lines appear somehow.

You cannot do Boolean operations with a mesh and a bunch of points. Boolean operations are for volumes defined by surfaces and a bunch of points doesn't have volume. You could convert those points to a volume and then convert that volume to mesh:


text:
Can't join objects with different materials
I'm trying to join multiple objects with different materials(Ctrl+J). When I join them they disappear in render view.
I was trying to assign materials to different mashes, but it doesn't work!
I just don't know what to do
This is my blender file:
https://drive.google.com/open?id=1w6xj5XGGIMKtyS8n-4XUSqpCFBkTOaAx
There is flower model and 4 materials: green for flower stem, flower leafs and flowers
I joined flower stem,leafs and flowers but it shows only flower stem in render view.
edit: sorry, I forget to pack textures into .blend file

So...
When you want to join multiple objects, be sure that they have UV maps with identical names.
It was not obvious for me.


text:
How to create a rubber sheet with ball bearings causing indentations
I am new to Blender and I have a very specific image I wish to create to illustrate a new theory of physics.
Specifically:
1) I would like a rubber sheet, where the rubber sheet is held rigid (cannot move) at all edges (perfect would be a circular rubber sheet).  Lets say it should 25 x 25 units if square, or 25 units diameter if it is a circle.
2) At every unit intersection (eg 0/0, 0/1, 0/2, 1/0, 1/1, etc) attach a 0.25 unit diameter helium filled ping-pong ball below the rubber sheet, which will cause the rubber sheet to gently stretch upward, like a shallow umbrella.
3) At 3 arbitrary locations (two a couple of units apart and one far away from the other two) attach very heavy 0.25 unit diameter ball-bearings on top of the sheet, which cause the rubber sheet to bend down sharply, but only for a narrow distance. My goal is for the upward curve to be totally overridden between the two close balls, but for the upward curve to rise a above the three balls between the distant ball and the pair of balls.
Can you give me a rough description of how to do this and I will figure out the details.  No animation is necessary - just a static image after the balls have distorted the rubber sheet.
Any help would be greatly appreciated.  In the meantime I will continue learning blender basics.
[UPDATE]
In response to requests for a draft image, here is what I mean.  [You can see by my drawing skills why I need blender :-)]
I have drawn the image looking up from below.  You are looking through a transparent rubber sheet with 3 heavy balls "above" pulling it down and many helium balls below gently pushing it upward.
The surface is generally raised, like a shallow umbrella, but 3 spots have very heavy ball bearings pulling the rubber umbrella down.  The empty circles are helium filled balls under the rubber sheet.  The filled circles are the heavy balls which began above the sheet.

I have figured out I need to use a cloth sheet made of rubber.  I tried putting the rubber sheet and one heavy ball above it in a blender image, but when I ran it, both fell straight down.  So, I need to figure out how to anchor the edges of the rubber sheet so it doesn't fall.  Then I need to figure out how to add balls that float (have negative gravity?) below the sheet.
Thanks for any help!  I am slowly learning blender.  Very cool tool!

Could you please add some reference image of how should this look? It's a little bit hard to actually imagine it without making it.

The final goal is a static image destined for a physics ebook (and maybe print book) with a semi-transparent surface (representing Space) so you can see the light balls (negative particles) generally curving space upwards and the heavy balls (positive particles) sharply, but locally, curving space downwards.

I'd go for a Soft Body plane, subdivided suitably, pinned around the edges. You can then animate the balls, each set with Collision. The trick will be in tuning the Soft Body settings to get the appropriate behaviour.... probably disable gravity, set the mass quite low, set edge springs quite soft. If this sounds suitable I can provide a more detailed answer.

Do the light balls curve space upwards as a whole, or does each ball curve space locally?

I know you are looking to illustrate a physics idea and some of the solutions are using the physics aspects of Blender, but I was able to make a rough approximation of your illustration using the Sculp feature with dynotopo on. There are many ways to model this with or without physics.

@ScottMilner The theory is Quantum-Geometry Dynamics and a good summary is at https://www.quantumgeometrydynamics.com/blog/wp-content/uploads/2016/08/An-Axiomatic-Approach-to-Physics-new-draft.pdf
In the theory, there are space particles with weak negative gravity in a regular grid, and matter/energy particles with strong positive gravity spaced far apart.  All particles affect all other particles instantly, so the effect is space is generally upward curved pushing particles apart but locally strongly downward curved near positive particles. Does that answer the question?

@RichSedman Yes, that sounds great.  Why a Soft Body plane rather than a Rubber Cloth plane?  I was assuming a physics simulation with the helium balls rising until the rubber stretch was tight and the steel balls falling until the rubber stretched tight would get me to a stable state that I could capture as a static image.  But I am totally happy with your idea too, if it ends at an image I can use!
So far I can't even get the steel ball to stop falling through the rubber sheet.  Then my pinning stopped working.... I get one piece to work, then others fall apart.

@Bfoot  I'm new enough to Blender that I'm not even sure that the Sculp feature and dynotopo are.  If it can give me a generally upward curved surface (like a shallow umbrella) with a few deep dimples, two closer together, one far away from the other two, then I would be very happy with that.  I don't need to actually physically simulate it.  Thanks!

@MarkBC It’s difficult to get rigid bodies to react properly to soft body so manually animating will be mich easier than physics. I generally prefer soft body over cloth as there’s more control over how it behaves as there’s a lot more options to tweak.

Though I'm not completely sure I understand exactly what you're trying to illustrate, I believe I've found a solution with Animation Nodes. While Animation Nodes has a bit of a learning curve, it can help you produce very precise, procedural results. I think this will be a better solution than simulation. First, download and install the add-on in the link above.
Once the add-on is installed, create a new Animation Nodes tree in the Node Editor:

In Animation nodes, you can add nodes two ways. The first is with Shift + A, which brings up the normal menu. If you are unfamiliar with the nodes, they can be hard to find, so you can search for nodes with Ctrl + A.
First, we need to make a plane to represent space. Add a Grid Mesh node. the $X$ and $Y$ divisions represent the number of vertices, not faces, so we'll need to add $1$ to the dimensions that we want. Let's do $25$ by $25$ units, and $101$ by $101$ divisions. We'll add an Integer node so we can set both Divisions at the same time:

In order to view the mesh we are creating, add a Combine Mesh Data node and a Mesh Object Output node:

Next, let's add the bearings. In the 3D View, add $3$ Empties. I chose the Single Arrow display type and set the Radius to $5$. In the N panel, lock the Z-axis location. Select the $3$ Empties and press Ctrl + G to group them. Name the group Bearings:

Add an Objects from Group node and select the Bearings group. Now, add an Object Controller Falloff node. Set the mix type to Add. Since the bearing's radius is $0.125$, set that as the Offset value. Experiment with the Width value to find something that depicts what you want. I chose $1$. Now, the most important part is the Interpolation. Since gravity has an inverse square falloff, my guess would be that you want the Quadratic option. You can visualize interpolations with the Interpolation Viewer node. You can also create a custom interpolation with the Curve Interpolation node:

To apply the falloff, add an Offset Vector node. Enable the list input, and plug in the Vertices list and the Falloff. Set the Z-value of the Offset to however deep you want the ball bearings to go. I chose $5$:

Result:

Now, let's add the upward curvature. We'll do that with two Directional Falloff and Interpolate Falloff nodes, a Mix Falloffs node, and another Offset Vector node, configured accordingly:

Now we have 3 "ball bearings" with a gentle upward curvature. You'll notice I made the upward curvature Quadratic, but that can, of course, be configured differently.

This is the bare minimum, but I want to go a little bit further. Let's draw a grid over the top, so that it renders cleaner. We can do this by creating Splines (curves) that follow certain edges. First, lets create a script to select edges. Add an Expression node, and plug in the Edge Indices list from the Grid Mesh node, the Integer node that sets the number of Divisions, and another Integer node. Name them according to the picture below. Use the gear icon to set the output type to Generic List. Paste in the following code:
[x[i*(n-1):(i+1)*(n-1)] for i in range(2*n) if ((i<n) and i%o==0) or i==n or ((i>n) and i%o==1)]

This code will isolate every o runs of edges in the grid, so this currently gets every $10$ edges of this $100$ by $100$ grid. To turn these into splines, we need to loop through every run and join them together. Add a Loop Input node and give it a Generic List iterator, a Vector List parameter, and a Spline List output.

Add a Convert node to change the Generic input to a Edge Indices List. Then add a Splines from Edges node and a Connect Splines node:

Add an Invoke Subprogam node and a Curve Object Output node, configuring settings as shown, and you should have a wireframe.

To make it look a little nicer, crank up the Divisions and adjust the Bevel Depth:

^^^ $501$ divisions, gridline every $10$, Bevel Depth of $0.4$
NodeTree:

Gif:

Rendered Result (two sets of overlay lines, thick lines every unit, and slim lines every $\frac{1}{4}$ unit):

With transparency:

Download the .blend (requires Animation Nodes):

(Plane divisions turned down to $400$ to fit on Blend-Exchange)

Beautiful answer Scott. I'm partial to AN but don't have the skills to achieve your answer. But given the question, it may be the best solution and one that I hope speaks the language MarkBC wants.

@Bfoot Thanks! Is there a part of the answer that goes too fast to follow?

I think your answer is spot on. It's direct and quite clear without any missing 'black boxes'. It does require a decent knowledge of geometry, math and some programming which I may assume MarkBC has more than me. Then it will be only a matter of having fun with learning Animation Nodes.

While Soft Body and Cloth will simply react to Rigid Body objects, the opposite is not true - it's quite difficult to get Rigid Body objects to correctly interact with Soft Body/Cloth. There are workarounds (such as that described here (https://blender.stackexchange.com/a/96789/29586)) but getting the interaction to be convincing is difficult and involves a lot of trial and error.
Instead, we can simply animate the falling heavy balls and allow them to displace the fabric. Additionally, rather than using 'floating spheres' for the opposing forces with pinned edges we can use the Soft Body goal over the whole plane to oppose the heavy weights (and disabled gravity) - as the fabric is pressed down, each vertex will attempt to return to its original location, effectively pushing back up again until it reaches its 'rest' position.
So, starting with a subdivided plane, add a Soft Body modifier. Adjust the Goal Strength to adjust how much the fabric should resist deformation - 0.0 = no resistance (no "upthrust"), 1.0 = do not move at all.
Create 3 spheres and add Collision physics to each. Adjust the Inner collision setting if required - but keep it to not more than the radius of the sphere (this sets the collision 'zone' and keeping it less than the radius will prevent overlap of the zones within the mesh; reducing the tendancy for the vertices to 'push through' the mesh). Enable Edge collision in the Soft Body Edges properties - this will slow down the simulation considerably but will reduce the chance of vertices passing through the meshes. For even better collision, enable Face collision - if you have enough time to wait for the simulation to complete!
Animate them moving down through the fabric. This should produce a result similar to the following :

Note the Soft Body settings I've used at the right-hand-side of the image. In addition, I decreased the Soft Body Solver Error Limit from 0.1 to 0.01.
Blend file attached


text:
Is it possible to animate a soft body object?
What I'm trying to do is create a few bouncing jello cubes. I can make a jello cube. And I can scale it to make it bounce. I can't do both.
Scaling it requires Soft Body Goal to be enabled, but enabling Soft Body Goal glues it in place and prevents it from actually bouncing around the scene.
Bring in more of these objects, and you have another issue in that they don't want to collide. You can sort of fix that last issue by tacking on a Collision modifier but it seems a bit buggy. And I'm also back to not being able to scale the cube. As user3800527 suggested I tried tacking on a Rigid Body to that, but that just led to some really weird behavior.
As far as trying to make the soft body animateable, I've tried just plain animating the scale of the object as well as animating the Soft Body Edge Spring Length property, but those don't appear to affect the simulation while it's taking place. Soft Body Goal is able to slightly fix this, but when you turn that on you're trading that for the soft body's freedom of movement.
Here's an example blend file showing some of what I've tried so far, layers 1-3 have different things I've tried, and all of them have the bottom cube scale from 1 to 2 from frame 20 to 23. http://pasteall.org/blend/index.php?id=43836
So is something like this even currently possible in blender?

Could you post a blend file or screenshots to help demonstrate your problem?

Sure thing, I've updated my first post with example animations and a blend file with examples of what I've tried on layers 1-3.

Yes this is possible
First create a floor cube large wide but not that high.
Make it a Passive rigid body.  (so it wont fall down its the floor)
Next a bit above it add a cube, subdivide it a few times.
First add rigid body collision (convex hull, source deform).
Next add softbody to this cube.
It will drop and woble on the floor.
oh and for better results use damping on soft body.
such cubes can bounche on eachother as well if you copy them shift D

That almost works, but not quite. It acts like there's now two objects, an invisible rigid body and a visible soft body, and the two are separate. With Soft Body Goal on, the soft body acts attached to the rigid by a rubber band, which leads to some odd behavior. Turning Soft Body Goal off gets us back to the soft bodies ignoring each other again.

Looking at it i think you used subdiv modifier as well (apply it), also check your colision object type (use detailed mesh).
and you might put in more calculation time (as when they colide) adding mass and damping more can help as well. .. Note goals is there for objects who naturaly spring back, ea sponge.

Well that pretty well solves the "jello cubes don't like to interact" issue. Thanks! Now all I need is to figure out how to animate the scale of a soft body object during the simulation. Right now it only seems to respond to scale and property changes if it's not currently being simulated.

not exactly sure what your after, but pressing i (loc scale) creates a key on time line that locks place and current scale.
move timeline, go to the objects property (location rotation scale) change scale and press again i in the scale property itself, as this time you wouldnt want to lock position (i asume).

That's exactly the problem. Soft Body Simulations don't care about that. Give it a try, keyframe a soft body cube's scale. Hit play. It'll stay scaled at 1 unit through the simulation. I'm not sure how to describe it, but it seems like soft body sims basically rip the vertices off the object and animate them. Select the object during animation and you can see the origin of the object getting left behind.

hm it might be too complex for the softbody simulation, it allready has to check collision physics. if the deformation isnt to big, you might make use of an extra hidden object to collide against. you can do a lot with blender but sometimes your on the edge of what it can do.

Yeah I guess so. Well the good thing about open source software is that it's always improving. :) Thanks for all the help!


text:
Video Aspect Ratio Not Vertical
I'm trying to create a vertical animation for a YouTube short. I have set the resolution, so it has a greater height than its width. But the rendered animation looks like the vertical was cut out of a standard horizontal 1920x1080, so there are empty sheds on the sides. How do I render this animation, so the aspect vertical ratio is centered or fit to the screen, like a YouTube or Instagram short or reel?

The only settings that really do control the output resolution are... The resolution settings:

It looks like you didn't set a vertical resolution output, but instead used a render region in your camera to try "crop" the render.
But unless you enable "Crop to Render Region", all it will do is restrict the render to the render region and output it in the image as per the Resolution setting.

Thank you for the emphasis on the Resolution settings being the only control for the output, and me not really setting it to a vertical resolution, it opened my eyes to the mistake I made. Having rendered the  animation as Image Sequences with a vertical resolution initially, I opened Blender again and forgot to re-adjust the resolution in the Video sequence Editor type. Thank you.


text:
Blender parametric modeling !help!
I have been trying to define a set of parameters that I can change and iterate over to make a number of different blobs or shapes depending on the parameters.
The scrip is as follows:
import bpy
import math
from mathutils import Vector

while bpy.data.objects:
    bpy.data.objects.remove(bpy.data.objects[0], do_unlink=True)

# Define the parametric functions with weights

def sin_func(x, y, z, w):
    return w * math.sin(x), w * math.sin(y), w * math.sin(z)

def cos_func(x, y, z, w):
    return w * math.cos(x), w * math.cos(y), w * math.cos(z)

def exp_func(x, y, z, w):
    return w * math.exp(x), w * math.exp(y), w * math.exp(z)

def tan_func(x, y, z, w):
    return w * math.tan(x), w * math.tan(y), w * math.tan(z)

def sqr_func(x, y, z, w):
    return w * (x**2), w * (y**2), w * (z**2)

# Define the arrays and weights for each function

arrays = [[sin_func, [1, 1, 1]], [cos_func, [2, 2, 2]], [exp_func, [3, 3, 3]], [tan_func, [4, 4, 4]], [sqr_func, [5, 5, 5]]]

# Set the number of vertices and the size of the bounding box

num_verts = 200
box_size = 4.0

# Create the mesh data

mesh = bpy.data.meshes.new('BlobMesh')

# Create the vertices

verts = []
for i in range(num_verts):
    x = (2*box_size)*(i/num_verts) - box_size
    for j in range(num_verts):
        y = (2*box_size)*(j/num_verts) - box_size
        for k in range(num_verts):
            z = (2*box_size)*(k/num_verts) - box_size
            weighted_sum = Vector((0, 0, 0))
            for func, weights in arrays:
                for j in range(3):
                    weighted_sum += Vector(func(x, y, z, weights[j])) * weights[j]
            verts.append(weighted_sum)

# Create the edges

edges = []
for i in range(num_verts-1):
    for j in range(num_verts-1):
        for k in range(num_verts-1):
            v1 = i*num_verts*num_verts + j*num_verts + k
            v2 = v1 + 1
            v3 = v1 + num_verts
            v4 = v2 + num_verts
            edges.extend([(v1, v2), (v1, v3), (v2, v4), (v3, v4), (v1, v4), (v2, v3)])

#Create the faces

faces = []
for i in range(num_verts-1):
    for j in range(num_verts-1):
        for k in range(num_verts-1):
            v1 = i*num_verts*num_verts + j*num_verts + k
            v2 = v1 + 1
            v3 = v1 + num_verts
            v4 = v2 + num_verts
            v5 = v1 + num_verts*num_verts
            v6 = v2 + num_verts*num_verts
            v7 = v3 + num_verts*num_verts
            v8 = v4 + num_verts*num_verts
            faces.extend([(v1, v2, v4, v3), (v5, v6, v8, v7), (v1, v3, v7, v5),
            (v2, v4, v8, v6), (v1, v2, v6, v5), (v3, v4, v8, v7)])

#Create the mesh object

mesh.from_pydata(verts, edges, faces)
obj = bpy.data.objects.new('BlobObject', mesh)
bpy.context.scene.collection.objects.link(obj)

#Deselect all objects

bpy.ops.object.select_all(action='DESELECT')

#Select the blob object and make it active

obj.select_set(True)
bpy.context.view_layer.objects.active = obj

#Apply scale and rotation to the object

bpy.ops.object.transform_apply(location=False, rotation=True, scale=True)

#Set the origin of the object to its center

bpy.ops.object.origin_set(type='ORIGIN_CENTER_OF_MASS')

#Export the object to an STL file again

bpy.ops.export_mesh.stl(filepath="blob.stl", check_existing=False, use_mesh_modifiers=True)

However, the resulting STL file doesn't have anything in it after taking like 20 mins to run. I can open the file in Solidworks but there isn't anything there.
Can someone help point out where im going wrong? The latter most part

Have your exported successfully any collection of objects not created by your script?  Do you have a valid selection in the Blender UI?  Have you consider a smaller test where ...num_verts = 4?  For testing you may want to separate the lengthy creation as opposed to export.

Are you asking about the time consumption of the Script or not?

It would be way more useful for you to choose a title that reflects the content of the question better than including meaningless text like "!help!". All questions here are asking for help - this adds nothing, just gets in the way as noise. If you choose a good title it may attract more people who might be able to help.

I gueses the best thing I can do is try to clarify. I am not using the blender gui. But certainly can if needed. I guess I just don't see many guide on have to make an object with parametric functions in an efficient manner. I believe what I am doing is possibly the right way to do it. But I'm VERY new to blender as in this week.

I am then going to eventually use that script in a bpy module in python to iterate over different parametric function inputs to generate 2 arbitrary but different objects. Sorry if I suck at posts I'm a super introvert

When I set the filepath as "blob.stl" I get "Permission Error: [Errno 13] Permission denied: 'blob.stl'" . However, if I change the filepath to something like "C:\Users\yourUsername\Desktop\blob.stl" , I'm then able to see the stl file. I don't have Solidworks, but I downloaded FreeCAD and I was able to open the stl file with ease. (can also import .stl in Blender, but thought I'd try external CAD):

and the above shape matches what the script made in blender:

I chose for num_verts to equal 10 for this. Also, I'm not gonna make the assumption that this shape is incorrect, but it's very large, chaotic, and not what I imagine a "blob" to be shaped like. Maybe there're some math logic mistakes?

Ok thanks that actually helped a lot!


text:
Aligning rotation to target along z axis

why brown object not snapping to face like other gray object in scene while i turn on all required setting.i locked rotation setting to avoid  unnecessary rotation. object should rotate along z-axis only using snapping option is it possible.

With this snapping options, and in particular with "align rotation to target" checked:

Moving an empty, you can notice that the Z axis is align to the target face normal and Y axis is up for the lateral faces:

But strangely this is not the case for a mesh:

Though, if you place a first mesh, then duplicate it, you can have the wanted result:

Duplication is not actually needed, you can place the object on a first face then move it again.
In my opinion (this is only an opinion), the code behind may do so that the rotation is minimal when snapping.
PS: locking rotation is not needed here.

Thanks a lot for the explanation, this is great! :). It's probably worth mentioning that it snaps the origin point, not any face (but maybe that's obvious to others).

@JachymMichal, unfortunatly the former answer was incorrect...

Thank you for explanation.this is very helpful.it's solves my problem


text:
Bones don't follow animation
I have another problem,
I started a new model for animation, but I don't know why bones don't follow anymore the cloth modifier?
Previous model works fine, in this model I cannot find a solution, can someone help me where I forgot to apply something?
https://www.youtube.com/watch?v=WXmAsbhc6fk&feature=youtu.be
How to make it work and follow the armature
https://www.youtube.com/watch?v=Q0KMj4zwO8c&feature=youtu.be
again I followed this tutorial
https://www.youtube.com/watch?v=r1w4VoVPixg&t=14s

Comments are not for extended discussion; this conversation has been moved to chat.

was trying to make simple flag model like i did in previus model and bone still rotating like in this model


text:
What would be the best way to add groves to this control knob?
I am learning blender for school and I need some help, I want to add groves to this control knob in the picture, but I'm not sure what would be the best way to go about it.
Should I try editing the mesh? Or should I try to construct a cutter piece?
Thanks in advance if you can help.

One easy way to do it is to use the Simple Deform modifier / Bend mode:

Create your segment:

Array it (enable the Merge option of the Array modifier):

Give it the Simple Deform modifier / Bend mode:

You can continue to work on the segment as much as you want, when you're glad with the result, apply the Array and Simple Deform modifiers (keep the Subdivision Surface if possible), merge the vertices:

Thanks for the help, I'll go and try this method/modifier now

If you meet any problem please let me know  ;)

Hi I've managed to get to the point where I am adding the simple deform modifier, but it doesn't go the way I want it to, only if I set the origin to my reference photo does it bend the way I want it to, how do you rectify that?

apply the rotation in Object mode (Ctrl A) and choose Z as axis in the modifier

Ah okay, didn't know I was supposed to apply the rotation, thank you very much, it's done now


text:
Is there a way to apply a boolean modifier to a metaball?
Is this possible with Animation Nodes?
If not, how do you convert a metaball to a mesh that can then have modifiers applied, and by extension can you do this simultaneously for multiple frames of an animation so you don't have to do it manually for each frame.


text:
How to add keyframes and change the shape key (named shrinkwrap) value with Python?
I'm animating a model (a lightsaber) and I want the blade to ignate. I found a method that uses the shrinkwrap modifier but I don't know how to code it with python. This is the animation with the shrinkwrap value= 1.0
And this is the animation with the shrinkwrap value= 0.0
It's kind of difficult to me to explain, but basically is adding keyframes and each keyframe added needs to have a different shrinkwrap value. I'm also open to other methods, but I need to code the animation.
This is what I have so far:
import bpy

lightsaber = bpy.data.objects['Lightsaber']

lightsaber.keyframe_insert(data_path='location', frame=1)
lightsaber.keyframe_insert(data_path='location', frame=4)
lightsaber.keyframe_insert(data_path='location', frame=10)

Thank you.

Your "shrinkwrap" is a shape key.
You have to access it through the object data, in the shape_keys part and get the key_block by its name (or index).
That can be:
import bpy

#Get the object
lightsaber = bpy.data.objects['Lightsaber']

#Get the shape key
shrinkwrap = lightsaber.data.shape_keys.key_blocks['Shrinkwrap']

#Assign values and insert keyframes on it

shrinkwrap.value = 1
shrinkwrap.keyframe_insert("value", frame = 0)

shrinkwrap.value = 0
shrinkwrap.keyframe_insert("value", frame = 50)


text:
what workflow should I use to turn this photograph of a contour gauge into a curve in blender?
I have smooshed a contour gauge into an object so I can model a "cradle" that will hold it in a box.
What is the workflow to transfer the curve from this image into blender?

I deliberately took it at an angle, because even if I took it from straight above there would be camera distortion.  I assume there is some software which can use the grid in the image to make the correction easier.

To "remove" the perspective in the picture, hugin seems to work.  Use the advanced interface to mark the horizontal and vertical lines and change the projection type to rectilinear

hugin can then output a resampled version of the photo usable in blender.

In a fresh blender scene, convert your camera from Perspective to Orthographic, and clear out its rotation (alt-r) and set the position to [0,0,20] (just someplace high on the Z axis will do).

Set the Background Image of your camera to be the undistorted image.

You also need to adjust your scene Output Properties resolution x and y to match the image, otherwise the pixels will be rectangular instead of square and your image will be distorted.
If matching the size of the physical object is important (it is to me) then create a cube or plane that matches the size of an object in the scene.  Since my photograph includes a grid of 1-inch squares I set my Scene Properties > Units to Imperial Inches and created a 1-inch cube.
I then adjusted the camera's orthographic scale until the 1-inch blender cube matched a 1-inch square in the camera's background image.
At this point you should be ready to create an object to trace the curve.  I started by making a Bezier Curve.

I converted the curve into a mesh and extruded it to create a 3-d printable object I can use to compare against the original object.