text:
Create mesh from four curves (Loft)
I want to create a smooth mesh using four curves.  I want to animate the curves so that it changes the mesh.
Basically, I have the four curves(black lines) in the picture.  Just want to cross link them (red lines) and make the mesh.

Suggestion.  Please consider an armature of 4 sets of 4 bone sequences.  Hook modifiers on curves are possibility.  You may want to search question with the word [loft] or [lofting]

are your curves subdivided? You could hook each vertex of your mesh to some empties, then parent the empties to the vertices of the curve...

You can also consider a [spline ik constraint] on armatures.

@moonboots would like to have many points > 50 on curve to produce smooth mesh.  I will probably need to subdivide it to get the right shape when I create animation.  But to get started doesn't have to be subdivided.

Related https://blender.stackexchange.com/questions/1503/how-to-make-uv-loft-like-3ds-max-in-blender-using-curves https://blender.stackexchange.com/questions/746/lofting-between-splines https://blender.stackexchange.com/questions/138901/loft-tool-in-blender-2-8/ https://blender.stackexchange.com/questions/278462/create-mesh-from-four-curves-loft https://blender.stackexchange.com/questions/301152/how-could-a-loft-object-be-closed

Here's a shot at making Loft Curves: a reasonable GN emulation of the AN node in @Chris's answer.
It modifies a curve comprising an arbitrary number of ordered, acyclic splines, of any resolution or type.
The strategy is: first, to create 'cross-ribs' on the incoming splines, by resampling the incoming splines to a desired U resolution, and doing some index-wrangling to switch spline indices and point-per-spline indices:

The cross-ribs simplify smoothing of the geometry in the loft (V) direction, by converting the ribs to Bezier curves, and extending or retracting their curve-handles. Loft Curves assumes the smoothing is already set on the incoming splines:

The Loft Curves GN group employs the above sub-groups as shown. After the ribs are smoothed, they can be resampled to the desired V resolution, and a Mesh Grid can be mapped to the ribs, by index:

A few extra nodes are included to permit the setting of smooth-shading, material, and to flip the face-normals of the lofted mesh, if needed. The group also outputs the UV coordinates of the mesh, for use in texturing.

(Blender 3.3)
Edit: in answer to  @alibaba_0000 's query.
When transferring attributes by mapped indices, you must find a mapping from the destination indices to the source indices. You tell the destination where to find the attribute on the source.
The 'Map Indices' cluster, in this case, performs the mapping illustrated by a few examples, below:

.. try a couple by hand.. you'll see. If you can find a neater way.. let me know  :)

This works! Could you explain what the index mapping is doing?

@alibaba_0000 It takes N splines with M points each, and re-jigs the  indices to match M splines with N points each, (Rotating 'grid' indices through 90° without the expense of mapping, rotation, 'closest', for attribute transfer).

@RobinBetts ... Thanks :) in hope I will be able to learn from you one day.

@RobinBetts Thanks. This method is really good for constructing meshes (tried a few other things as well).  Re-arranging the indices is really janky though.  If I understood correctly, the indices get ordered: s00,s01,s02..., s10,s11,s12,..., s20,s21,s23...       and the index manipulation changes to: s00,s10,s20...,s01,s11,s12,...,s02,s12,s32... where the splines are sn0,sn1,sn2...

@alibaba_0000  Hehe :)  not sure! I need a picture in front of me .. ( which is  how I worked it out )  As soon as I get a moment with  a machine, I'll  send you one...

@alibaba_0000 ... see edit.

Geometry Nodes
Edit - Previous version with Merge by Distance was quite limited ... so here is better one :)

start-end connection is bezier now
easily change grid density from modifier panel
current setup handle extreme curvature
start/end surface fits at its position

The example uses ...

Two curves (Start / End)
Instanced Bezier Segment on Start curve with end point at End curve
Points position used as attribute for Grid object

i just "stole" your solution here to post it here: https://blender.stackexchange.com/questions/278553/double-curvature-surface-from-curves-generated-with-geometry-node - hope you don't mind.

@Chris No problem ... justQ - Why you didnt reused RobinBetts's one ... seems to be way flexible :)

Because i could quickly understand yours. Robin's solution are often from his genius mind - but the downside for me is: i don't understand them quickly.... ;)

@vklidu The bonus thing is very sweet of you.. thanks.  this one did  take me a while.. I started off down completely the wrong road..

@RobinBetts - I could value it through my own pain :) I felt glorious just for simple indices pairing thing ... so your remapped index list is (in such a flexible way) is in miracle category for me. Thanks

with help of the amazing free add-on animation nodes you can basically do it with 4 nodes: (if i don't count the smooth node)

Going to try this weekend

@Chris ... Nice and simple :) Thanks ... I just can't make it work. Last blender that works with addon is 2.93 ... even with that a mesh object just disappears ... can you check my file ? Thank you for help

@vklidu: You are right. It works "only" on my animation nodes version for Blender 3.4 - i just tested it on older version, there it doesn't work so i would assume this is a bug in older version of AN.

and if i remember correctly i have compiled my own animation nodes add-on because i am working with python 3.10 - so if you compile it for yourself (i don't think you have a mac, but if you have i can send it to you) and then this worked.

ok, just copied my animation nodes folder from 3.4 to 3.2.1 and it works with your file: [1]: https://i.sstatic.net/DAcpE.jpg

and 3.3 works as well:  [1]: https://i.sstatic.net/adNSl.jpg

so maybe just update your AN?

Yes, Mac user here :) I haven't been compiling addon before ... I even didnt know adding can be compiled :( Sorry

ok, just send me an email (my email is in my profile) and i can send you the files if you want to. Do you have a M1? I don't know whether this matters but it might be a reason why it doesn't work....and of course you have to have python 10 for your Blender installed (that i know for sure matters, because it is compiled for a specific python version)


text:
How to use the vector of another different object as information for material node?
I'm pretty new to blender so probably i'm going to say wrong terms or function in this question, feel free to ask for a better explanation if necessary.
I have created a material tab that makes the images in the planes show only when the camera is looking at them at a certain angle (like the NPC in the Doom 1993 game).
In this case I set the angle to be 90° degrees so that when the camera turn past that point, the plane in the front became invisible and the one on the side shows up (In this example I used only 2 planes for simplicity, normally there would be 8 planes each one turned by 45° in an octagon like shape).
I use some math with vector and arcosine to do the trick as shown in the example.
There are two colored planes on the side to show better what's happening: when the plane is red it means is showing the guy, when is green it don't.

This is the node used for each plane:

The rotation works fine, the true problem is that the plane is still acting like... well, like a plane.
I wanted to make the guy rotate and follow the camera at the same time (Billboard if I'm correct).
My first thought was to use a simple locked or damped track set on the camera, but unfortunately this is the result:

The plane shows both the guy because they are always facing the camera and so of course the camera is always in the 90° cone.
So here's my idea:
I make two sets of planes, the first one (Planes 1) will be invisible and immobile, while the second set (Planes 2) will have the image to show, the material and the locked track.
My idea was to make Planes 2 show not using his vector (that if I'm correct its use in the material tab) but the vector of Planes 1, so that the camera take in consideration the angle or vector of Planes 1 while Planes 2 will be free to rotate.

Is it possible to make a link like this without using any script? If it isn't possible, can you recommend another solution without any script to make a character rotate and act like a Doom 1993 game NPC?
Again, I'm sorry for any error while typing or incorrect terms since I'm new to blender and this is my first question, I tried to be as clear as possible but, if necessary I'm ready to give you any information that you need to resolve my problem.

This is the blend file if necessary

Please next time place given code into your Q via Edit. Thank you and welcome :)

You're on the right track.  Well, tracks.  You need to both billboard this guy (kinda billboard him, we'll get to that) and check the angle.
So first, let's see why we need to billboard him:

Let's say your little dude is running at a diagonal to the camera.  We're still seeing his side, but the camera isn't pointed directly at the plane.  Just like the monkey on the left, he's going to get distorted by the angle to the plane.  So we always need the plane to be pointing at the camera.  We can do that with a locked track constraint.  Because your planes have had rotation applied (+Z is up, +X is right, and plane normal in object space is -Y) we'll do a locked track, lock Z, track -Y to camera.  Now we can see that issue is fixed:

Why locked track instead of damped track or track to?  Because although we want our little dude pivoting on the up/down axis to track the camera, we actually do want him foreshortening if the camera is ever raised above him.  That's why we're only kinda billboarding him: there is an axis where we won't.
Now, we still need a way to indicate facing, so that we can mix between front and side views.  But because we're tracking the camera, we can no longer use our object coordinates to measure facing.  -Y is always facing the camera.  We need something new to indicate facing.  We'll do that by creating an empty at the location of the plane, then parenting the plane to that empty.  Our empty will carry the information about facing, even as our plane rotates to face the camera.
Since we're using an empty to measure facing, we now need to compare a vector of the empty to the +Z vector of the camera.  That's not so easy to do in pure nodes (it's possible, just confusing and painful.)  Let's slog through it with drivers instead, doing everything in a way that's totally clear.
We want to know the world space vector associated with one of our empty's axes.  To find that out, let's make another empty, move it in one axis, parent it to the other empty, and then subtract the locations.  We can use drivers to acquire those positions into value or combine XYZ nodes:

Now, we'll set up the nodes to compare that (world space) vector to where our camera is pointing:

We convert the camera's +Z vector into a world space vector, then we drop the world space Z component (we don't want it switching views when we adopt a bird's eye view!)  We normalize the vector and compare it to the vector we created with our drivers.  If the absolute value is greater than 2^0.5/2 (cosine of 45 degrees), then we're facing front or back; otherwise, we're facing to the side.  We can use our knowledge of this facing to mix between two different texture lookups.  (Ideally here, we'd actually be mixing between four, or more, different lookups, but I'll leave that problem for another day.  This is already a pretty long answer.)

Images are not packed into that file, in order to spare their server some bandwidth.

This kinda work even if for some reason the plane doesn't get affected by shadow, do I have to put a principled Bsdf on the color input on mix color? Also, could you please continue the explanation on how to expand with 8 images? I even made a question apart with more details: https://blender.stackexchange.com/questions/244601/how-to-switch-beetwen-two-or-more-textures-with-material-nodes

@ErCoso I'm doing emission, so there's no shadow.  If you want shadow, you can use a diffuse or a principled (or even a glossy).  But you probably don't want shadow: the actual geometry that will be shadowed here is just a plane, after all.  I'll check out your other question.

If i understand you right, you need the track to constraint.
So select your human/plane, add object constraint...

choose track to and choose your cam as target.

you can - if your camera should also look always to your plane add an object constraint to the cam as well with target "plane".
result:

source: Stack Exchange

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

sort: votes


text:
How do I "Glue" an object to the surface of a mesh that is using a modifier?
I am trying to stick a tree to a path as the path begins to spiral/screw along the Y axis.
I have used the screw modifier to make the path spiral and then parented the tree using 3 vertices. This doesn't work, the tree becomes deformed and doesn't follow the scale, location or rotation of the path it is parented to.
I have tried using both a plane and a line curve for the path, neither work, they both have the same undesired effect. I have also tried using all of the constraints both individually and stacking the ones I think could work. I have tried parenting by 3 verts plus adding LOC,ROT and Scale constraints. No luck their either.
Is there a way to do this where the tree doesn't deform and actually stays on the surface of the path?

Related https://blender.stackexchange.com/a/113989/2214

If you need position one tree ... use Snap tool > Face Center, ALign Rotation to Targen https://blender.stackexchange.com/a/167718/2214

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


text:
Cannot light portions of object with point light
I am setting up a simple scene with only a single object, a truck, and a point light. It seems that regardless of where I put the light, the hood (among other portions) of the truck won't be lit. Here's an example:

My first thought was that it was a problem with the materials on the truck. But the material on the hood is the same as that on the top and sides, so I don't think that it is the issue.
I also replaced all of the materials with the default one (diffuse intensity 0.8 and specular intensity 0.5) to see just the contribution from lighting more clearly:

Is there some other reason that might be making it impossible to light certain portions of the object?
Other possibly relevant information: In the images above, the light is a bit above the driver's seat of the truck, but the problem remains even if it is directly on top of the hood. I have had better luck with Hemi lights, but would prefer to use point lights if possible. I am using Blender Internal rendering. I am also happy to post more images (the car rendered with shadeless textures, the actual blend file, etc) in the follow-up.

Check the normals of the model

@cegaton: Thanks for the suggestion. I tried moving the light away from the model and making it a bit brighter, but I still am unable to light the hood: example rendering here.

@DuarteFarrajotaRamos I looked into the normals a bit, and found that Mesh -> Normals -> Recalculate Outside did change the shading a bit. Here's the new result. Much of the truck is still completely unlit though. Could you point me to a resource explaining how to deal with the normals better?

If anyone would like to take a look directly, here is a download link to the blend file. There are only three objects in the file: the camera, a car, and a point light. The car has been decimated a bit to reduce the file size, but I don't think that shouldn't affect the lighting issue.

Your model seems to have some shading issues beyond a simple one-button-press fix, was this modeled in Blender? I can only take a look at the model later tonight if no one beats me to it.

@DuarteFarrajotaRamos No, I imported an obj file from Shapenet, so I can't be sure of its origin or how it was modeled.

Taking a look at your model, it was clearly made in a CAD-like solid modeling or NURBS base software. It has very messy geometry and awful topology, there are sever normal and shading problems that cause these artifacts. I don't think there is any simple one-click-fix for this, other than manually cleaning up. Add an Edge-Split modifier to the whole car, then separate mesh by chunks with Ctrl+L > P > Selected, and recalculate normals afterwards. It seems to be producing some mild results, though it doesn't completely solve all problems

I believe the light is too close. The Dark areas of the truck are shadows from the lit areas of the truck.

I'd say it's because of the normals split in a custom way and imported with the mesh, https://blender.stackexchange.com/questions/76513/strange-black-shading-cannot-fully-light-mesh-cycles

While im not a Pro. I Think, I THINK. You should try increasing the strength of the Light. Or try using multiple lights. I Could also say Try to Transparent the background and Raise the color of the background to a bright color Preferrably a Bright White This will make the Background transparent, And the objects in the rendered image will be Nice and bright.
If you want to have the background grey i won't reccomend the latter.
One of my renders of a character for one of my games. With one default pointlight just above the head, Not bright, I Would like it more bright.
Now i have changed the Strength of the Pointlight to 900.
As you may notice the ribs are more bright And so are alot of the other parts.

I tried increasing the strength of the light (to 1000) and making the background white. Here is the result. It seems that the areas that were previously lit are now brighter, but the areas like the hood which weren't lit at all still are completely black.

You didn't make the background transparent.

Good catch, thanks. This is the version with a transparent background. It unfortunately didn't seem to affect the shading on the truck much though.

Hmm, Try to send me one with the background brightness lower Still transparent. If it doesn't work then give me the link to the truck and i will show you my attempts.

Here's the transparent version with darker background. If you'd like to take a look at the model directly, here's the folder with the obj and mtl files, and here it is imported and joined in a blend file.

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


text:
Can you apply an action to an armature that has more bones than the one that created the action?
I'm trying to create mocap animations for my characters in Unity. I currently use character models and animations downloaded from mixamo.com. I've just created some mocap animations with Brekel pro body v2, and I have imported the bvh file into Blender along with one of my models that were imported as a collada. I am trying to assign the bvh animation action to the mixamo armature. I've changed the names of each bone to match the names of the bvh armature, and the only difference is that the mixamo model has more bones than the bvh. It has a toe, eyes, head top, and extra spine bone where the bvh model does not have them, but everything else is the same.
When I assigned the bvh animation action to the mixamo armature, the animation plays but the rotations seem off and it doesn't look as good as when I play the action on the bvh armature. I've tried changing the type of rotation (ZXY Euler, XYZ Euler, etc.) but it hasn't helped. I'm trying to get the mixamo armature to make the same exact movements as the bvh armature.
Are those extra bones causing the issue? If so, is there a way to apply this animation to only the bones they share? I need to keep the current mixamo skeleton.
Thanks,
Clownthulhu
Edit:
Here are some added pictures of the problems I'm experiencing.
The first image shows the bvh armature on the left and the mixamo one that I need to keep the same on the right.

This shows the mesh of the mixamo model in the middle of the animation as well as the bvh armature during the animation. It also points out the problems I'm seeing and looking to correct.

As far as I know, you just have to set keyframes and whenever you change any part of the armature, just select all the bones and set a keyframe to 'whole character'. If i'm right it should now work as a normal set of keyframes and not anything special for armatures or something...

How would I go about setting keyframes? I know that I can click the "insert keyframe" button and have it set to whole body, but I currently have no animation on my mixamo model. The animation is on my imported bvh armature. I clicked on my mixamo armature and went to the action editor and selected the bvh action. Now there are a ton of keyframes already there, but when I play the animation it doesn't move quite right on the mixamo model. I just tried inserting a whole body keyframe for each frame but it just made more keyframes and did the same messed up animation.

Have a look into re-targeting deform armature to bvh armature with constraints.  Mostly copy loc and copy rotation and track to,  GLOBAL space to GLOBAL space.  Once you have the retarget rig set up giving a reasonable result, you can bake the visual transforms as your new action on deform rig.

The toe bone shouldn't be a problem, but an extra spine bone might be, as it will have children that are animated by the armature. Because of this it is likely that the transferred animation may never look the same.
To fix this I'd suggest adding an extra control bone to the mixamo armature named after one of the bvh bones and constrain two of the spine bones (the dupilicate and another) to move based on its rotation. A picture of the two armatures would make this easier to explain.
You may want to check that the bone rolls on each bone in edit mode match between the two armatures.

I just edited my post to include images. I checked the bone rolls and they were different between the two armatures. I changed the mixamo bone rolls to be the same as the bvh, but that just made the rotation issues look worse (the model went into almost a T-pose and its legs crossed in an X). I then looked into trying to constrain two spine bones like you said, but Blender wont allow me to constrain to another bone, and it says I can only choose an object to constrain to. I also compared every bone each armature has in common and they all had the same rotation values throughout the animation.

@Clownthulhu to constrain to a bone, first select the armature they belong to as the object, then it should let you select the bone. Looking at the two armatures a direct transfer might be hard to achieve. The second picture does suggest a mismatch in some combination of bone roll, bone orientation or rotation order.

Ahh okay, I didn't realize you pick the armature first and then the bone. I tried using constraints and it helped keep my armature in the same position as the bvh but the rotations were really off. When I tried to constrain rotation as well, it didn't come close to matching the rotation and still looked bad. I will try to play around with bone roll values some more and see if it helps. Thanks.

So I've solved my problem in a way, but I'll leave it here in case anyone runs into a similar issue.
Instead of exporting from Pro-Body as a bvh, I exported as an fbx. Blender couldn't open the fbx, so I used Autodesk's FBX converter (http://usa.autodesk.com/adsk/servlet/pc/item?siteID=123112&id=22694909) to convert that fbx to a collada file. From there I just imported that collada into blender and was able to apply the animation that came with it to my model and it was a very close fit to the original animation. I could make minor modifications from here in Blender and then export it to Unity as an fbx for use. I hope this helps if anyone comes across a similar issue.
However to answer my original question from the very beginning, you can apply an action to a model with more bones. Even that extra spine bone that had children didn't cause an issue as it just moved along with the other spine bones.

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


text:
Spawning Cube on Same Level
I'm trying to learn how to use blender but everytime I try to model... it spawns on different levels! There is a big space and I dont know how to keep them on the same level

Welcome to Blender.SE. New objects are added at the current 3D Cursor location. Are you moving it up and down?

Press G + Z to move an object up and down. When you add a new object, it goes to where the 3D cursor is.

When adding a new mesh/object into Blender, it will be added where your 3D cursor is (looks like a red and white circle). You can move the location of the 3D cursor by left clicking. Also, if you want to move the objects so that they are the same level, change their position on the Z-axis. This can be done in multiple ways

The properties window: by default, the properties window will be on the right side, under Outliner tab. To move the 'level' of an object (where it is located on the Z-axis), click on the Object tab (looks like a cube) and change the Z value under location (1st is X-value, 2nd is y-value, 3rd is Z-value). To put all your objects on the same level, make sure all of their Z-values are the same.
The other properties tab: By pressing the key shortcut "N" or dragging the + (top right of your 3D view box) to the left, you can bring up the other properties tab. The Z-value of the objects location will be under 'Transform'.


text:
Particle velocities not working as expected
I'm trying to create a foam based on particles velocity.
Here is a folder with some tests of the problem.

Cycles particle info node implement colour of velocity to a instanced spheres very... wrong (opposite to the display of velocity inside particle system), but if connect output of velocity to normal channel of material it seemes to display colours right. But it is not a solution...
How to use this node to proper colour of material?

Feeding the velocity into a Math or a Color Ramp node will be averaging the X,Y,Z values of the vector and this can produce unexpected results - especially where you have a mix of positive and negative values.
Instead, you can use a Vector math Dot Product node to determine the magnitude of the Velocity by passing the Velocity into both inputs of the Dot Product (which will give the magnitude of the velocity, squared) and raising to the power of 0.5 (to square root it - to get the speed) and using this Value output as a scalar representing speed. This can then be passed through a Math node to scale it and on to a Color Ramp to generate a colour based on the speed.

I copied Rich Sedman's node setup, and still got some unexpected results. the particles seem to continually slow down while falling, and do whatever they want once they have made contact with and object.

Here is the result:
Weird Particle Colouring

I didn't spot this as it's as another answer so didn't get notified. I've had a look and it appears to be a problem with the Particle Info Particle Velocity not becoming close to zero once it's collided - it seems to stay at a high negative zertical velocity as if they are still falling - rather than a problem with the node setup. Very strange. I'd suggest adding this as a new question - perhaps someone has seen this before and knows of a solution.


text:
How do I lock hair / particle orientation?
I have a particle system where the top and bottom of the particle are different colors. The particle should rotate when a field is applied and show the other color when it's upside down.
This is not happening. Below I've shown the rotation progression.

They just..swap colors?

How do I stop this from happening?
Instance object and appearance of top and bottom of particles:

https://drive.google.com/file/d/18r91klJSHk3fBrrRuODgpjT5Bedg9M8B/view?usp=sharing
here's the blend file

Weird. It seems the rectangular particles can only bend over backwards. As soon as they the start going face first towards the ground, they quickly turn around (on the Z-axis) and continue in the same direction, but now bending over backwards again. (Blue side being the back and orange being the front.) They don't arrive at the tipping point at the same time, so at certain moment some are turned while other haven't yet.  It seems to be a inherent property of the Orientation Axis (in Particle Properties > Rotation) which is set to "Velocity / Hair" . I wish I had an idea how to fix it.

Is this a bug then? I can't imagine that auto-flipping things in a physics simulation is desirable behavior

I suspect it is by design. Imagine an upside down (somewhat rigid) L-shape. If that L was a hair on a head, you would want to have it point in the same direction as the wind, and not bend over backwards in the wind. So it would have to turn. It seems the particles behave a bit similar to a wind vane. I must say though, I have very little knowledge of the inner workings of Blender and I'm not qualified to say with any certainty if it is a bug, feature, or anything else.


text:
Require help with multiple lights in EEVEE creating a clean and sharp black/white shading (shadows and light bounce)
I'm currently trying out different things for an animation series I've planned and need help with creating sharp and clean black/white shadows and light bounces, when the range of - for example - two (or more) point lights overlap (while casting shadow and light onto a ground). The scene contains a simple plane for the ground floor, an actor and two point lights, which are positioned in front and behind the actor.
I have here two pictures (four with the node setups), that I hope will illustrate, what I'm going for.
First example (not what I'm going for, just to illustrate certain points):
The first one is with the ground plane having a simple diffuse shader. As you can see, the two point lights cast two seperate shadows onto the ground while also lighting the ground corresponding to their position. A little "specular" overlay of white can be seen especially on the right side (which overlays the shadow). I would like to remove this little speck, but keep the lighting of the ground itself (can be seen much better in the second example):

Second example (what I'm going for, but with the adjustments I mention below):
As you can see, for the floor I want to go for a clean break of black and white. The two point lights cast again two shadows and also light the floor in a sharp circular form. But also here, there are those two "specular" specks which completely overlay both shadows (or, the "speck" from the one point light overlays over the shadow from the other point light).

What I want is to be able to use multiple point lights in this way, which each can cast their shadows and the "specular" circle not to overlap any shadows (but still keep the usual circle of light)
Specular is disabled on both point lights, though I think I would have to include the removal of that somehow in the material nodes of the ground material, though I can't figure out how.
I hope you can help me somehow. Should the description of my request not be clear, please say so, and I'll try to edit the question, to make it clearer.
I'll include my test blend file (with packaged resources), so that anyone who wants to help, can take a look at every parameter and my setup.-
Thank you very much in advance.
.blend file: https://drive.infomaniak.com/app/share/139668/5c09308a-4b00-4600-925d-ec3cdd494f07
Edit 24.04.21:
It is possible to render on different render layers, as soon as I have more than one light that illuminate the same region, which will probably be a common ocurrance. It is possible, but I would rather do it directly, if that's possible.


text:
How can I connect two bones head to head (not head to tail)?
I have a problem with my Armature, to be more specific, it's 3 bones which makes the problem.
I have a Pony character which I wanted to rig, so I made an armature which works great, but I can't connect my Root bone to the Front legs and neck section. (see picture) I watched a few tutorials on the internet and read this question, but all they said was to flip the bone from the Head to Tail and connect them together. I don't want to flip, but connect Head to Head.
Can I do this? I can't move the legs and the neck/head section from the Root(Spine) bone. Here are some pictures. I marked the Root bone with a White circle and the other bones which I want to connect with Red circles.

I want to congratulate you on coming back and sticking with your question. (I've seen other new users just leave.) Not only did I close and reopen your question after reading your edit, but I think I may of solved your problem too. You already fit in with the SE Q/A system very well. Welcome to the site, I hope you can find and give much help here.

You can not "connect" (parent) a bone's head to another head, nor does tail to tail work. As I showed in my answer parenting bones to other bones is the normal way to connect them. The manual's page about armature structure explains how bones link together.
However, there is another option, using the bone Child Of constraint.*
In pose mode, Under the Bone Constraint tab of the properties window add a Child Of constraint to each bone you want to be connected.
Simply set the Target to be the armature, and then your "root" bone.
The Set Inverse button will keep the bones position. (as you may of noticed it jumped to the targeted bone's head).
The Clear Inverse button will move the bone to the traget's location.

The downside to this method is it will not work in edit mode.

* The manual warns against using a Child Of constraint to create chains of bones.
I don't see any problem in this instance, and it is the only way to connect bones' head to another head.

Yeah, okay, i fixed it, i just made a Root bone and from there i go whoever i want, it's a bit complicated how all this Rigging works aparentely :/ I just want to make a game with animations... I saw a few tutorials about rigging, but this all was just about Humanoid characters but not animals...
I don't know if that what i made would give me some issues with animating, but this was the only sulution for me 'cause when i made it with your tutorial, my head was the root... Not the "Belly" what causes to be unable to move the head... Here's what i made http://i.imgur.com/Xx7byHx.png

(Ran out of character...) Thank you for your kind answers! I hope i'll get more support from this forum :) I want to learn more about 3D Modelling in Blender. Ou, and sorry for my bad english :D This is not my native language ^_^
Regards ^^


text:
Proportional editing functionality
No matter what I tried only the immediate area around the center rotated and deformed.
According to everything I could read about proportional editing I am supposed to be able to increase the range of influence by scrolling my mouse wheel or using the Page up or down keys.
The mouse wheel just zoom the scene like always.  And page up or down does nothing at all.  Did they change the functionality in 3.0?
Thanks

please make a screenshot when you are trying to scroll your mouse....

https://docs.blender.org/manual/en/latest/editors/3dview/controls/proportional_editing.html

In order for the mouse wheel to work with proportional editing, you need to be doing an action with that option "ON", like G(Move) S(scale) or R(Rotate)
An example is:
In edit mode select a vertex from your mesh
Turn On proportional editing O
Press G (move)
And now you can scroll the mouse to make the Proportional editing area Bigger or smaller.

Thank you so much.  That does the trick.


text:
How to prevent Texture Stretching
As seen in the first picture the image texture (with Texture coordinates) works ok

But when i try to move the image texture up the wall this happens

is there a way to fix this i tried to rotate the Controler plane and it did prevent the stretch but made it so the texture was in 2 places as seen below

is there a diffrent way to fix this ?

a way to fix this would be to use a UV unwrap, I supposed this is not waht you're using? But maybe share your file (don't forget to pack your image)? https://pasteall.org/blend/

Does it solve your issue? https://blender.stackexchange.com/a/249069/2214

it solves my other problem but not this one still thx for the help.

How did it fail? If you are still looking for answer share your blend ... Or use uv texturing as suggested.


text:
Problems with Textures
Hello i have 2  problems with textures
1.i use (Texture Coordinates) with image texture on cube (or any mesh that isn't flat plane). the texture is in 2 places at the same time how to fix this

here is a file with the problem

I'm not sure you can avoid that

It seems to be duplication of https://blender.stackexchange.com/a/249069/2214 ... second issue seems to be solved with the same post.


text:
Keyframes not saving rotation
I select the rotation, but when I go to save it as a keyframe, it will either revert immediately, or wit until I move to the next frame and back and it will still have reverted.Video to problem

Something in your video looks strange. The viewport and timeline say you are on frame 27, and also the number in blue frame which usually shows where the playhead is shows a 27. However the playhead itself, the vertical blue line, is on frame 8. Also the timeline shows that only X rotation has a keyframe on frame 27, however the colors on the Location and Rotation values are all the same, indicating they all have keyframes there. Maybe you could upload the file to investigate this further? I guess a file with only the keyframed camera would be enough. It seems like you are not on frame 27?

@GordonBrinkmann - The thing with Timeline is remapped time. Go to Render Properties > Frame Range > Time Stretching >  where the Old value is set to 30 (or New value is set). So I guess keyframe is saved, but at frame 27 (that is highlighted).

@vklidu I didn't see the remapped time in the video... better explain that in an answer to Isaac, I don't need to understand it because I never use this ;)

@GordonBrinkmann ... OK ... sorry for that, I direct my comment to you since your comment sounds to me it is strange for you so I thought you would be interested what is behind. Issac's issue is rotation, that is caused by another issue. BTW You are right, there is not time remap visible, the presence of it is indicated by timeline and frame number offset.

@vklidu The reason why it is only saving the rotation for X instead of XYZ as you mentioned in your deleted answer is that he's not keyframing in the viewport with I > Insert Keyframe > Rotation but in the Timeline with Right-click > Insert Keyframe which only keyframes the selected channel - in this case X... this is clearly visible in the video.

@GordonBrinkmann ... so you are ready to create answer :)

@vklidu The problem is not the single X rotation keyframe - it's the reverting of the rotation setting as the question explains. And I guess that's because the keyframe is not placed on the frame where the playhead is... so you are probably indeed correct with your time stretching - which I never use as I said so I will probably not be able to answer that. The question is not "why is there only a keyframe on X?"

@GordonBrinkmann I completed the answer here to finish this conversation :) The combined answer is - it saves rotation as suppose to at real frame 27, frame 8 with playhead line is just a visualisation of modified time (that is my part). Rotation is not saved because axis name has to be selected for keyframing from contextual menu in timeline (your part of correct answer). :)

OK ... so the thing here is

to add keyframe by selecting Insert Keyframes operator from contextual menu (right-click) in Timeline (or Dope Sheet) you have to select a channel name in the left row. (Thanks to @GordonBrinkmann comment)

or press I > All Channels (instead of right-click)
or press I in 3D Viewport.

Just a footnote ... The timeline's line at frame 8 and timeline's number in header at frame 27 indicates you are using Render Properties > Frame Range > Time Stretching ... like Old value set to 30 (or New value like 330).

In this case - the keyframe is saved, but under frame 27 (see highlighted keyframe in timeline) and specifically in your case - the keyframe is saved only for selected X axis (for the reason described above).
You rotated Y axis that is not selected - so was not saved.


text:
Transfer Attributes from One Geo-Node to Another
TL;DR How do I transfer attributes from one geo node on one Object to another geo node on another Object?

Hey guys, trying to write an attribute in a node tree that is used on one geometry node modifier on one Object and then read that attribute in a different node tree used in a different geometry node modifier on a different Object so that one Object can act as a data source for multiple other Objects.
The way I'm trying to do this right now is according to the below diagram. The problem I'm having is demonstrated through the red lassoing in that I am expecting to be seeing (1,1,1) for my Sample Index node out field, but I am rather seeing (0,0,0):

I don't understand enough about Geometry Nodes to know why the above doesn't work, but learning from previous questions I've posed to this website I'm this time going to include a .blend file for those more knowledgable to explore right away which those interested can find at the top of the post.
Thanks for reading!

In "PostModifierScaling_Source" graph, try to add a "Geometry to Instance" node between "Group Input" and the first "Store Named Attribute" (the one with "postModifierScaling_factor") nodes. The issue seems to be that you store attributes in "Instance" domain, but you have no instance (check in the Spreadsheet Viewer...).

@StefLAncien My tree still isn't working BUT that did resolve the crux of this post in that I'm now getting (1,1,1) when reading the relevant attribute, so clearly something else is wrong that I'll have to look into. TYVM!

To quote user StefAncien,

In "PostModifierScaling_Source" graph, try to add a "Geometry to Instance" node between "Group Input" and the first "Store Named Attribute" (the one with "postModifierScaling_factor") nodes. The issue seems to be that you store attributes in "Instance" domain, but you have no instance (check in the Spreadsheet Viewer...).

Doing as such resolved the issue my question posed, although my specific tree still isn't working, but that's for my own investigation from here.


text:
Scale a face to always fit the same point in global space in an array modifier
I'm new to Blender and trying to learn how to create very basic geometric objects for development in Unity.
I thought it would be a fun project to attempt to build a roller coaster rail using an array modifier. This worked fine, except I would like the main support cylinder to always be set at a set world space, or for lack of a better term 'the ground'.
In the image below, the brown line represents the ground.

I would be willing to rebuild the model and start again if necessary.
Sketchfab File

I'm not sure it's possible to do without accepting Array modifier or adding another modifier in stack together with Array (e.g. Boolean which could cut everything located below the "ground" plane)

Array modifier alone can't do the job, it's just capable of repeating a given geometry, but surely you can model a rollercoast the way you have in mind. Could you be more precise about what you want to achieve and the given limitations (e.g. no pyhton, no boolean, no..)?

I don't necessarily need to use the array modifier. This was just an exercise in 3D modelling in Blender. I don't have any specific limitations.

Some of possible solutions are to add one more modifier or to apply exhisting one and to continue working with mesh with changed geometry due to that.
Non-destructive way - adding Boolean
Place the rollercoaster where it should be; create ground plane and position it accordingly (so no flying meshes etc). Don't apply Array modifier; instead add one more to stack - Boolean.
Before:

After:

Note that you should position Boolean modifier after Array modifier, so there to be information for Boolean that rollercoaster is arrayed.
Note that Boolean is modifier dependent on mesh itself; results of its work depend on topology of your meshes, their complexity etc.
There are cases when Boolean modifier fails, see related question. That's why it's a good idea to check your meshes for both double vertices and non-manifold geometry. Also check them on Ngons which boolean might not like too.
Destructive way - apply Array
You may apply Array modifier and modifications made by it will become real. You can continue edit them in any possible way:

Turn on snapping, set it to Face mode, select bottom face of the rollercoaster's support, and grab it by Z axis;
It's possible to even join meshes, select all and use Mesh > Faces > Intersect function (when selecting all choose Self-Intersect mode of the operator in Last Operator panel or by pressing F6).

Joining faces may be undesirable, of course (you may separate them after cutting though).
you can add a loopcut to support, turn on again snapping and grab it by Z axis to position loopcut accordingly (pretty much the same as grabbing face).

I get the error 'Cannot execute boolean operation' for the first method. http://i.imgur.com/HPiSfbM.png

Adding the subsurface modifier fixed it for me for a moment but then it stopped working again.

@Ambo100 It's not completely clear for me, you accepted the answer but told that it stopped working. So did it work for you? What is the problem? If you feel it's long to explain add a file to blend-exchange and I will try to repair it, or you may stick to using file I uploaded.

Here is my model. (Before I added the subsurface modifier to the plane. When I do that, and add the boolean modifier to the track, some of the support beams are cut off by the plane and others are not. I have tried scaling the plane to be large but it doesn't seem to help. This animation might help to explain what I mean.

Let us continue this discussion in chat.

It would be very good if downvote could be explained; I'm just interested in the reason for that.

I don't think there is really any other way other than making the cylinder longer at the bottom. That way, you could "Apply" the Array Modifier, and then cut through all the cylinders in one straight line with the Knife Tool (K).


text:
Howto get the filepath of a rendered animation frame with python
I want to modify every frame in an animation after it has been saved as an image. Since bpy.data.images["Render Result"] doesn't have associated data I need to load it from disk.
How do I get the path of the last rendered frame in a render_post handler?

The filepath is stored in:
bpy.context.scene.render.filepath

However there is a function to find the output filename for a frame (the same function blender uses internally).
output = bpy.context.scene.render.frame_path(frame=10)

example use:
>>> bpy.context.scene.render.filepath = "/test/some_###_anim.png"
>>> bpy.context.scene.render.frame_path(frame=10)
'/test/some_010_anim.png'

You'll probably want to use context.scene.render.filepath and append the frame number with (using str.zfill(4) where str is the frame number as a string and 4 is the number of digits), and extension using context.scene.render.image_settings.file_format, converted to lower case (using str.lower()).

What about '#' in the output filepath?

'#' indicates padding, so you could count the number of '#'s after the last slash (in case folder names have hashes) and use that instead of 4

You'd also have to remove the hashes from the output path using str.replace('#', '')

Could you update your answer with a complete code example for all this please?

Now that would make it too easy wouldn't it ;) Figuring it out by yourself will teach you something. If you're still stuck tomorrow then I'll code it for you.

use of str.zfill(4) and file_format.lower() are incorrect, the # characters can be in the middle of a string and fileformat enum doesnt always match the extension. Getting this right is quite involved, an API function is provided to do this. (noted in my own answer)

The expression you want is bpy.context.scene.render.frame_path()
Calling frame_path without specifying a frame uses the current frame.
import bpy

def handle_render_write(scn):
    print(scn.render.frame_path())

bpy.app.handlers.render_write.append(handle_render_write)


text:
How to capture lighting in video shots?
How do I best capture the lighting in a video shot so I can easily insert rendered objects into the scene that are correctly lit?

While there are many subtleties and nuances to your question, the following should deliver reasonable results with equipment you may very well have around you or possibly borrow.

Use a DSLR and use your widest lens. The Sigma 8mm fisheye and a full 35mm sensor allows one to capture edge to edge sphere shots, for example.
Do a bracketed exposure series of your set in enough directions to cover the scene. For example, with the 8mm above, it is three directions. If you require four photos to deliver your 360 degree view, you would require a set for each exposure. Depending on your scene's dynamic range, pan to your first position and take photos at exposure, several stops down, and several stops up. -3, -1.5, 0, +1.5, +3 stops might be required, or fewer. Shoot raw to preserve as great a range as possible for each image.
Merge each bracketed exposure set together into a spherical merged image. An example might be Hugin or other such tool.
Merge the stacks of exposures into a single HDR scene referred EXR image from the layers of stitches. An example might be Luminance HDR or other such tool.

A single exposure will fail to deliver upon the "correctly lit" aspect of your question.
It is important to understand the difference between a scene referred and a display referred image here. Where a typical JPEG or such image is a low dynamic range and being bent to fit the 0..1 range, a scene referred image attempts to maintain the original scene's ratios of light levels being cast from objects. This is stored in a linear fashion and the values can range from zero to a theoretical infinity.
When a series of bracketed photos are merged into a scene referred file format such as EXR, the original values of the scene are reconstructed. These values will much wider apart than the 2.5 stops of light a typical JPG or PNG can represent1.
Granted that the above will only deliver an accurate estimation of the lighting at the given point you photographed your HDRI images. If you seek more accuracy such as a CG element nears a wall or other object, you would need to attempt to project the light values upon a placebo object to correctly estimate the inverse square law of energy (1/d^2). Project from view with some tracking might be useful here.
For further reading:

The VES technology white paper discussing the differences between scene referred and display referred data.
A solid description of the differences of file formats and their ability to represent HDR data.
Hugin panoramic and spherical stitching application.
Luminance HDR: http://qtpfsgui.sourceforge.net/

1: A middle grey card photographed and converted to a JPEG will land at approximately 48.45% value in sRGB. This translates to a value of 0.2 when linearized to display linear. If we double this, we arrive at 0.4 for one stop. Doubled again to 0.8 for two stops. 1.0 therefore can't express any greater dynamic range than a little over two and a tenth stops of light. Further complicating this is the fact that a standard camera will hold a wider dynamic range and curve this into the resulting JPEG or display referred format. This ends up baking both the sRGB curve and the camera curve into the resulting image, and it cannot be reasonably undone from these formats.

So what's your take on mirror balls?

Mirror balls are lower resolution and subject to drifting and shifting. Remember, if you want to get to scene referred linear values, you will need to stack at least a couple of exposures. A mirror ball can make this challenging for your software, as well as wasting a good chunk of the captured image that isn't the spherical ball. Mirror balls are typically used with grey balls for lighting references, not for HDRI construction.

The easiest thing to do to get similar lighting in your scene is to use an HDRI environment map (tutorial on how to get it: http://www.otake.com.mx/Apuntes/Imagen/EnviromentMaps/). Basically, you take a picture pointing in every direction and stitch it together later in GIMP or Photoshop.
Once your map is set up (and you want more intense lighting) throw in a few light sources where the sources are in the HDRI map.
You can also use the Mirror Ball approach (a mirror ball is a glossy ball which reflects the scene arount it).
To make a mirror ball map, take the frame with the mirror ball into photoshop or GIMP and crop it as closely to the edges as you can. Then, load the mirror ball into Blender. Add it as an environment map and choose mirror ball from the "type" dropdown. After that, you simply render.

In a making-of of a hollywood production I saw that they held something like a big christmas ball into the camera before shooting. Do you know something about that?

@Maccesch, yeah, there called mirror balls. It's a quick way to get a (most) of an environment map. It's usually enough to adjust the lighting. (Blender also supports mirror balls, so it's super easy to use them.

could you add a how-to of this to your answer please?

There are two steps to setting up this kind of lighting system.
The first step is to find a good HDRI environment map. It doesn't need to match your scene exactly, just so long as it gets a good approximation of the overall scene. I recommend that you look for good HDRIs from here or here, or just Google search for 'HDRI environment maps.' To use one of these images, add an image texture to the world environment (world panel of Properties bar) and load in your image.
Once you've done that, you need to place in the same lighting sources as in the original video. There are a couple of rules of thumb for figuring out where the lighting sources are. First, look at people's feet (or any other vertical object). You should find a shadow cast for every major light source in the scene. Or, if there are any reflective surfaces, like glass or metal, you might be able to see reflections of the light sources that you want. Once you've identified the light sources in the video, it's just a matter of duplicating them, then tweaking positions and emission intensities of the light sources until you have the effect you want.


text:
Shadow from texture not showing up because of a transparent shader
I've used a texture on a plane for this sunflower, but instead of only the diffuse part of the mix of shaders casting shadows, the transparent shader is also casting a shadow with the shape of the 2x1 plane, where as I said earlier only the flower should cast the shadow as it is a diffuse shader.
The texture is packed into the blend file.

Texture link:
http://s2.postimg.org/thhlmfi15/tilemap.png

Pretty sure I packed it in, I put a link to the image file though.

Transparency Shadows
While the Blender Manual page says:

For direct light sampling, use transparency of surfaces in between to produce shadows affected by transparency of those surfaces.

the tooltip is perhaps more clear:

With that option disabled, as in your case, the alpha channel of the texure won't be considered for shadows so you'll get the light occusion from the actual geometry (a plane).


text:
Why is my model coming apart when posing its armature?
Hi I am trying to animate a bird rig that I made but when I try to pose the armature the bird model comes apart, almost like the faces are moving independent of each other.
I am curious why or how this is happening. I actually like the effect of whatever has happened  and am hoping to possibly apply whatever is happening to some other models. But so far I've had no luck duplicating it

I tried adjusting the weights, but I'm not sure if I did it properly, most of the models I make only have to have their weights adjusted minimally.

Please show your modifiers on the mesh, the armature modifier settings, weight paint.

Better could be a link of your file ;)

Maybe edge splits can cause this? Or some wrong playing around with shape keys and stuff like that? I don't know for sure, but long time ago I had similar problem...

@atomicbezierslinger I just uploaded a copy of my file. However I did have an edge split modifier that I applied to my mesh. I think your answer may be exactly what I did

@AdriansNetlis  please see below

Image above. A similar effect can be achieved with edge split and armature.  The mesh started as a cube.  This technique alone is a bit difficult.

Image above. Single Armature, two bone chains, no weight painting.

Image above.  Separation of faces.  Edge Split was applied. Vertex group created basis and key1 which is scaled smaller.  Bind armature to key1. Display basis.  Keys inspired by comment by Adrians Nellis.
Easier to control.
Footnote

Image above.  One armature, four bone chains.  No weight paint with brush, thus you see some vertices in undesired places. It seemed best not to have a weight paint exercise. Weights were modified with [limit total] value 1 in weight paint mode.  No artist merit here.  The first frames numbered <= 103 have the same shape key values.  Only the highest numbered frame has different shape key values.  Shape keys are not required for discontinuity of faces, yet changing face size is convenient.  Dotted Lines....

Create Mesh
Mark Sharp and Apply Edge Split
Scale Faces Smaller by .5 in edit mode.  Different faces have space between them.
Armature Modifier is parented.
Create Shape Key, Basis and Key1. Key1 scale Larger by 2 in edit mode. (2 * .5 = 1).  This visual appears to eye as closed surface.
The two different Keys minimize manual painting and promote easier parenting to intentionally produce surface discontinuities.
Use Key1 influence 1 full strength

I think this is what I did. I had no idea that edge split  modifier would have this effect. I thought it primarily affected how the mesh was shaded, ie to have smooth shading with sharp edges. Can you explain why it does this

It's how edge split works. In order to make the edges look sharp, edge split as it's name implies split the edge of an object where the user indicates. So imaging a cube with smooth shading applied, with 4 edges selected for edge split to act on. If the edge have 4 vertices it would now have 8 vertices after edge split is applied. Hence the single mesh will now have 2 sub meshes at the "edit level".

@m.fessler you should have received a few more points for your question above ... do you understand the part of Key1?

@hawkenfox That makes perfect sense, thank you for the explanation.

@atomicbezierslinger I'll admit I have never used or heard of shape keys before. I did look some information up on them and I definitely am going to start using them. I understand exactly what you are saying about how using them would make things easier. Thank you for all your help!

Im preety sure your Bird's mesh doesnt have all the faces connected to each other. One way to clean this would be to select your bird and go into edit mode. Then, select all the faces by pressing A. After, press  the "Remove Doubles" button. It should connect all the faces together, if not most of them.

I tried this solution and it partially worked. However I really wanted to know  how it happened in the first place so I could replicate the result, But thank you!


text:
Wind force field only works in the center of the scene
I am playing with cloth waving in the wind and I have the problem with positioning the force field (wind). It would only affect the mesh (cloth) geometry if the mesh is positioned in the center of the scene. Put in other words, if I move the force field to a different location (so that it could not affect the mesh) the mesh still waves in the wind. If I position both the force field and the mesh to a different location so that the force field would be aimed at the mesh, the mesh is not affected by the force at all. Waving only works when the mesh is positioned in the absolute scene center no matter the actual position of the force field. I am attaching the .blend file where you will find the cloth in the absolute center and the displaced wind source. The cloth is still waving. Is this a bug or am I doing something wrong? Thank you.

The Wind force field gives a constant force in a single direction. It's like a Sun light but emitting force instead of light, so You can imagine it as an endless flat plane emitting force.It's a global force. You can change only direction of it.
I checked your file and everything seams to be ok. It worked wherever I put cloth or wind source, so when You noticed it's not working You must've not back the animation to start position.

Thank you for testing my .blend file. This is really strange, because when I move the flag it is really not effected by the wind at all and I believe I do back the animation to start position. Is it possible that the version of Blender I am using is somehow buggy? I have recorded a video of what I see, you can check it here: https://youtu.be/GVVtPkkI0ds

Strange Indeed. Someone with Mac should test it. I'm running on Ubuntu and was testing the file on Blender 2.77, and everything worked fine.


text:
Require assistance to convert an stl file of complex (symmetric) voxel geometry to one with smooth surface in Blender
newb here.
I want to smoothen the model shown which comprises of voxels. I tried using a smoothen voxels add on, but it still does not solve my issue.
How could I smoothen the mode as accurately as possible, as I need it for experimenting in a wind tunnel. So, the surface should be as uniform as possible.
Or should I not use Blender for this?

Hello, maybe use a remesh tool (like the quad one in the Object Data panel > Remesh > Quad)?

"Or should I not use Blender for this?" What is it exactly that you want to use Blender for here?


text:
Interior mapping shader doesn't follow object rotation
I'm trying to create an interior mapping shader using blender.
I've followed this tutorial.
The problem I'm having is that it only works using plane oriented in one direction.

I've tried using the normal of the geometry but with no success.
This shader uses the actual rotation of the object, but this causes an issue with multiple objects using the same shader, and rotating the object 'cut' the projection.

Here is my blend file:

How can I make it so the shader works in any rotation (around the z axis), and not cut the projection ?


text:
Create new objects in a scene from point locations?
I'm using Geometry Nodes to generate a set of points within the volume of a mesh (a human character in this case), with the hope that I can take these points, export them into Unity, and use them as empty GameObjects to attach things to.
The point generation works great and does exactly what I need. What I can't figure out is an automatic way to use the points to create new Emptys inside my Blender scene, which can then be easily exported to Unity. I'm able to do it manually, but it requires me converting all the points to cubes, splitting them to separate objects, centering the pivots, and deleting the geometry.
Is there any way to directly hook up the position data from my Geometry Nodes points to new separate Empty objects in my Blender scene?

If you mean something like this ... Cube with Empties - enable As Instance under Object Info node ...

To realise instances ...
You can Ctrl+A > Make Instances Real, which will create individual Empty objects at those points (the GN object will still be there, modifier still on it, it won't be applied).
(Credit goes to Kuboå :) I just wanted to highlighted his comment here.)
I exported object with GN modifier as Alembic (.abc) and Imported back. Realised Empties come as parented to the Cube object that is now just an container without any vertex.

You can Ctrl+A > Make Instances Real, which will create individual Empty objects at those points (the GN object will still be there, modifier still on it, it won't be applied).

Do you want o create an answer? I'm ready to delete it :)

Nah, just incorporate it into yours so it's complete :)

This works great, thanks both of you!

The old Blender way :
Parent an empty to your point cloud object (With SHIFT + drag in the outliner or CTRL + P), enable vertex instancing in the point cloud object, Make instances real.


text:
Non-newtonian fluid
I am working on a project where it is necessary to simulate a non-Newtonian fluid.
The problem lies in the object's "non-responsiveness" to another object.
In my case, it is a car and a lying policeman.
The structure of the lying policeman consists of 3 meshes.

On the top is Cloth (to make a pillow look)
Fluid Domain
and Flow.

I don't know how to make the car react to the object, the keys and the collision don't work. Do I need go Rigid wheels? I really don't know. If I made it too complicated, I will be grateful for an explanation of how it can be done. And yes, i need that the car does not "pass" through a lying policeman, but rather moves over the landscape

Fluid

This sounds more like a softbody than a fluid to me.

My fluid is doesnt work rn. This "softbody" its cloth modifier. How i can a picture without post editing

@BoJo The same for me (as BlenderMaster15) ... what is the purpose of fluid in your workflow? Is you need just something similar to "pillow" physics use under Physics Properties > Softbody or  Cloth modifier with Internal Spings. If you don't plan to let pillow explode and splash blood everywhere :) BTW why "non-newtonian" fluid?

@vklidu. this is a physics project. The bottom line is that I can't do a car simulation. I tried all the ways, and through SoftBody/Collission. In general, the essence of the project is that the car could drive over a lying policeman as if on a landscape (that is, a simulation of movement through loc/roc)

@vklidu pt2. , and the lying policeman would sag under it like a pillow, but my car would pass by. Googling the article, I came across a liquid and tried to simulate the liquid so that the project was interactive, but now I would at least make the car move along the Z line, which I can't do (newbie in animation)

For a newbie quite a big bite :) A car rig is one big capture ... I don't know how complex your animation is (or what can be faked for just an illusion seen by camera), but try find out simplest way that match your final needs than sophisticated mechanism (or try to find free model of rigged car if you thing you would be able to control).

Just a quick tip until someone help you with something more sophisticated.

Cloth modifier

for "pillow" set under Physics Properties > Cloth enable Internal Springs
for Plane set Collision with Friction 30
for "wheel" set keyframed animation (loc/rot) ... no physics here

ill try it. Thank u for this one

IMHO this makes more sense than a fluid sim to simulate "a car and a lying policeman".

it doesnt working. how can i drop the video?

It would be better share your blend file ... try to delete all parts that doesn't participate on your issue and share via https://blend-exchange.com


text:
Override all materials' color but not transparency
The situation is as follows: I would like to create an image where the pixel values (RGB) correspond to the position (XYZ) of the point in space (world coordinate).
Create a new material, like in this post How to render world position pass, seems to be a good idea. And I could render a scene with this new material overriding all materials in a scene. However, this does not take into account the current material of the object, which defines its shape using transparency. For example, a leaf is usually a rectangle with leaf texture (which composes of both leaf image and transparent parts). So this way, a leaf in Position-Image will appear as just a rectangle, and it is not desired.
I am wondering if there could be another way around, ideally a render pass that would output such XYZ values, or a way to incorporate this material with the current material of a object. Manually do so for all object is not a good idea as they are so many.

I wonder if the answers to this question might give some ideas about mixing in an alternate material at the end of the node setup.

It seems that answer is more on manually fork the materials, which I am avoiding to do since there are too many of them.


text:
Scripting setup to save all Cycle render passes to a single EXR image
The answer here Save all render passes to a single EXR image to setup a node diagram to save all cycle render passes to a single EXR file is very useful. I am wondering if there is a programmable way to do the same with Python script?

The article here provides quite similar solution to my problem. The sample code goes like the followings for this diagram

#---------------------------------------------------
# File nodes.py
#---------------------------------------------------
import bpy

# switch on nodes
bpy.context.scene.use_nodes = True
tree = bpy.context.scene.node_tree
links = tree.links

# clear default nodes
for n in tree.nodes:
    tree.nodes.remove(n)

# create input render layer  node
rl = tree.nodes.new('CompositorNodeRLayers')
rl.location = 0, 200

# create SEP_RGBA node
sep = tree.nodes.new('CompositorNodeSepRGBA')
sep.name = "Split"
sep.location = 200, 200
links.new(rl.outputs[0], sep.inputs[0])  # image-image

# create VIEWER node
viewer = tree.nodes.new('CompositorNodeViewer')
viewer.label = "Alpha"
viewer.location = 400, 400
links.new(sep.outputs[3], viewer.inputs[0])  # A-image

# create COMBRGBA node
comb = tree.nodes.new('CompositorNodeCombRGBA')
comb.label = "Cyan"
comb.location = 400, 200
links.new(sep.outputs[1], comb.inputs[2])  # G - B
links.new(sep.outputs[2], comb.inputs[1])  # B - G

# create HUE_SAT node
hs = tree.nodes.new('CompositorNodeHueSat')
hs.label = "Violet"
hs.location = 600, 200
hs.color_hue = 0.75
hs.color_saturation = 1.5
links.new(comb.outputs[0], hs.inputs[1])  # image-image

# create output node
comp = tree.nodes.new('CompositorNodeComposite')
comp.location = 600, 400
links.new(hs.outputs[0], comp.inputs[0])  # image-image


text:
Meshes went crazy (shaky)
Hey all!
Little trouble here.
Meshes went crazy (shaky) when moving around in both viewport and rendered views.
i have a really huge scene. Some objects are very large and some very small.
This happens only to small objects.
Tried playing with clip distances, tried scaling everything up or down with no luck.
Video of the problem: https://www.youtube.com/watch?v=86Th-HOGY9Y&feature=youtu.be

Thank You

If you can't upload the file to Blend-Exchange then I would suggest creating a version of the file that has the least amount in it but still shows the problem by removing anything that isn't necessary and then upload to Blend-Exchange. For example, is it necessary for all objects to be in the scene to show the problem? Bear in mind that some people won't bother downloading a file if it is too big.

Your problem seems to be just clipping flickering.. Clip distance is set from 1mm to 1km, it's too much. Try increasing Start for the clipping distance in the Properties shelf of the 3D viewport > View rolllout. Related to http://blender.stackexchange.com/questions/8553/why-does-part-of-my-model-disappear-when-i-zoom-in-on-it-in-the-3d-viewport

Problem is gone after scaling up shaky objects and then scaling up all the stuff in the world to match the proportions accordingly.
And the problem was not just clipping flickering since it caused real distortion, which was also visible in rendered view.
Thanks Everyone for the attention.
UPDATE: The real problem was the huge distance from the center of the project (grid).
So if you are having similar problems - try moving problematic stuff near the center.
Peace


text:
Weird shadows in render view only
Good evening,
i have got weird shadows on my mesh. No matter what lighting i've got - problem is still there.
Clearly it has something to do with topology. But the topology is pretty good so it's strange..
It is possible to fix them in static character's posture, but when i animate the character - problem reappear since geometry changes again in those problematic places.
What's the magic button to fix all the problems? :D
Things i've tried:
* Recalculate normals
* Make planar faces
* Edge split modifier
* Remove doubles
Blend file: (somewhy doesn't show up well as it used to before)

This might sound crazy, but i fixed the problem by making the character even larger... :D
She is now 456km high :D

Your model is huge, and that is causing lots of problems.
Specifically for those shadows Ambient Occlusion is to blame. The model is so huge that even with the insane values you have for ambient occlusion, it only affects small creases in the model, but with great intensity. If you disable ambient occlusion however you get another issue: everything is dark.
The way you have set up your background node does not affect your model, so no environment light exists. You could either remove the camera ray constraint from the world texture, use a nice neutral grey for background and use the compositor to set up a background color, or keep it and add some lights to your scene.
However adding lights does nothing, unless you crank up the intensity to hundreds of thousands, another issue with the size of your model.
I'd say just resize your model to a more manageable size (something like a real human): then both AO and lights will work as expected with sane values.

Thanks for the response.
Tried totally without AO and only with lights - it's the same.
Most likely the size is the problem here.
Will let know how it goes.


text:
How to get rid of shadow from transparent area when background lighting only in Cycles
I have a scene with a a few planes that have a transparency texture (alpha map) set up. Lighting is done with environment texture only.

Problem is that with 0 diffuse bounces I get shadow action from the planes even at the transparent areas. I am looking for an Cycles only (no compositing!) way to get rid of the shadow action with 0 diffuse bounces.
For comparison, change lighting from background to sun (add sun, remove any input from world output surface, or set background strength to 0.0), and you'll see there is no shadow action from transparent areas of the planes.

My explanation: HDRI is like every pixel is light emitor. That means you will get shadows around the object. Try to use pole object, how it behaves in same situation. There should be shadows ale around that pole. Problem is with your HDRI, which has not any source of hard shadows. I would try to remove shadow casting from HDRI and tried to mimic shadows with sun light.

After asking around in IRC it turns out this is actually a bug with background light + transparent BSDF.
Reported https://developer.blender.org/T44599


text:
How to merge (boolean) two objects that share faces/edges
I'm working on some modeling for a jewelry box and I'm doing most of the modeling with primitives. I frequently end up doing something like the following: I want a bar with a bulb in the middle.
So I create a box: 48x10x10. Then I create a cylinder: 20x20x10. Both of these are at the origin. So this puts the cylinder right in the middle of the box and the top/bottom faces of both the box and cylinder are on the same plane.
At this point if you try to add a boolean modifier to one and select the other as the target; then you get some . . . odd results. Sometimes the initial one will work but then future boolean modifiers will cause crazy stuff.
I understand from previous posts that this has something to do with them sharing a face/edge/etc. and lovely divide by zero errors or something.
Is there a good way to do this type of operation? I just want these to objects to be one single one so that when I make another cylinder later I can cut a hole out of the middle of it.
In the past I've gotten around this by just not joining them at all and letting them overlap. Then when I pull the model into Cura for 3D printing Cura doesn't care about overlapping items or shared walls etc. But this is less than ideal for the modeling portion because any time I want to move the thing I have to make sure to select all the individual parts that comprise my "unit".
EDIT: Per requests here are sample images. Horizontal bar and cylinder are the items I want to join/merge/keep. The vertical bar is for a difference boolean to show the issue.

Now I am going to put two boolean modifiers on the horizontal bar. The first one is a "union" with the cylinder. The second is a difference with the vertical bar. This is the result. You can see by the highlighted wires and the odd interior faces that something strange is going on.

However if I move the cylinder up one unit so it doesn't have top/bottom faces on the same plane as the horizontal bar then it works as expected.

Sorry I don't quite understand what the final result will look like, can you please add in an image to help describe it.

Yes current issue image and desire result please, in meantime do you mean co-planar faces? https://blender.stackexchange.com/a/165574/2214  images needed anyway.

Ok I added images to show the issue. It probably is the "co-planar" faces issue @vklidu

Boolean operation doesnt handle this co-planar faces, known issue. That is why I used in thelink Remesh. In your case (from screens) it can be done by several ways.

like in your last screen higher cylinder, after boolean select upper vertices, scale (S) Z = 0, than delete (X) Limited Disolve (or after boolean ad another cube and cut it from both sides at once)
on top of cylinder add rectangle in edit mode and use Knife Project so you got edges on place were cube cross cylinder, select faces and extrude
or try Remesh Modifier with some luck https://blender.stackexchange.com/a/165574/2214

... or any other technique, but there is no direct setup for Booleans to fix this issue, sorry.


text:
When to use ".ensure_lookup_table()"?
For modifying meshes (in the hereunder example removing vertices), I use the script as follows:
        # Création du Bmesh
        maillage = bpy.data.meshes[nom_objet]
        bm = bmesh.new()
        bm.from_mesh(maillage)
        # Mise à jour des ID des listes verts et faces
        bm.verts.ensure_lookup_table()
        # Suppression de tous les points du maillage sur Ox
        points_a_supprimer = [v for v in bm.verts if v.co.yz.length < 1e-07]
        bmesh.ops.delete(bm, geom = points_a_supprimer, context = 'VERTS')
        # Modification du maillage de l'objet et suppression du Bmesh
        bm.to_mesh(maillage)
        bm.free()
        del bm

But I do not really understand if the use of ".ensure_lookup_table()" is relevant. What is the purpose of this code ?
Thanks in advance for explanations.

Totally unnecessary here. Relevant when indexing eg v = bm.verts[0].   Recommend testing against a tollerance rather than exact values.  eg v.co.xy.length < 1e-7

Ensure lookup table only needed after you change the BMVertSeq in your script

Thanks !Removing vertices does not change the BMVertSeq ?

It does but as previously mentioned only relevant if you are indexing elements in some manner before writing back to mesh, and / or freeing.  For most cases the enumerated elements matches the index order, but to be sure to be sure run the ensure for that element type  before doing so.  If you do try indexing without ensure lookup table  will get an error that you need to run ensure lookup table prior, indicating where and when to use.  For example script in question it is not required,  perhaps queston could be re-titled  When not How

@HikariTW see above. Always  needed if you intend to index that element.  eg in console try bm = bmesh.new() and follow with bm.verts[0] ..... error need to run ensure lookup table. .. remember this is an empty new bmesh so no sequence has been altered.

@batFINGER , when I remove the code line "bm.verts.ensure_lookup_table()" from the script, it continuous working right. And after that, if I add the code line "v=bm.verts[0]" I get the error message "IndexError: BMElemSeq[index]: outdated internal index table, run ensure_lookup_table() first". So, things are now clear for me. Again thanks for help.


text:
Steps to create new faces between 2 selected meshes?
I have a model of a sword. In the original model, the surfaces of the flat sides of the blade are flat. I'm working to inset the surfaces a little bit to provide some depth.
I've separated the the model into 3 meshes, 2 for the flat parts and the third being the rest of the sword.
Now I'm trying to figure out how to join the meshes so that they create new vertical faces along the edges, but I'm not really sure how to do that. This will let me move the flat surface meshes back into place but inset a few millimeters.
Hopefully the attached screenshot will be fairly clear. I've selected the two edges that I'm trying to join.

After applying "Bridge Edge Loops":

Do you mean something like "bridge edge loops"?

@ChristopherBennett Had to look that up and it does seem to be close to the right direction. However I'm getting some weird new geometry from that. I'm attaching a new screenshot after applying bridge edge loops for you to see.

@ChristopherBennett I'm guessing here, but I suspect the bridge problems may arise because the two meshes don't have equal edge counts. Sound right?

It's quite possible that's the case, but I'm not sure. There's a lot going on in that photo, it's kind of hard to tell. Any chance you could upload a .blend file?

Try tweaking the Twist factor when you use bridge edge loops (expand the panel in the lower left of the viewport right after using the operator)


text:
How to make cotton for Eevee
How could you make cotton, as below, using EEVEE?

did you try volume?

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.


text:
The difference between Factor and Image: How can I combine them?
I do not understand here what is the difference between Fact and Image:

Inputs
Factor
Controls the amount of influence the node exerts on the output image.
Image
The background image. The image size and resolution sets the dimensions of the output image.

How can I combine those two: Image and Fact ?

The easiest way is to try :) Instead of images you can set two colors in each socket and try what happens if you slide Factor or plug another black/white image into this socket. Seems to me self explanatory. The only attention is good to have on mind - top socket is for bottom image, second socket is for top image (and not like in other apps in oposite order)

There's a breakdown of what Fac does here

You dont combine Image and Factor.
You combine two images and Factor says how to blend these two images.
Color 1 (red) is background (BG)
Color 2 (blue) is like in foreground (FG)
Factor 0 = 0% of FG (second socket)
Factor 0.5 = 50% of FG and BG (equaly mixed)
Factor 1 = 100% of FG

As factor can be used also 3D textures or black-white image.

Note:
The order of items is one of Blender speciality :) logic comes from coding (I guess) from typing commands. Like first you order:
- paint red and then
- paint blue on top of red
... so sockets looks like these two rows. Other apps ussually use visual order - items for BG are lower, items of foreground on top.

It is easier to understand if you use a black and white image to combine the elements.
This black and white image has two values: 0 means Black, and 1 means White.

The Factor input determines how two other elements in a node are combined:
Whatever is black will be the color of the Top image socket,
Whatever is white will be the image connected to the Bottom socket.

All other values between 0 and 1 (different tones of gray) in the Factor image, will result in a mix between the two values.


text:
What is the proper way to make this robot arm?
this is really my first time making something in Blender without a tutorial. I am trying to make this robot arm, but I am unsure about the proper method to do so. I have outlined the object I am trying to create in red and my current attempt is also attached. I have used a boolean modifier to create the circular shape for the shoulder of the arm but it has far too many vertices which lead to too many edge loops lower on the arm. The arm becomes smaller lower down and the topology gets messy because of the extreme number of edge loops. I want to ensure that I am practicing proper technique and creating good topology. Should my circle have less vertices? Or is there a good way to reduce the number of edge loops as the arm goes down further? If I am using any terms incorrectly you can also feel free to correct me. Thank you so much!

Since you are asking for "proper" ways: avoid that big circular ngon on the top. Also try to model without booleans to keep the topology as quads. Watch: https://www.youtube.com/watch?v=Bc52fcrHvAA also spend a few hours reading through the pages of https://topologyguides.com/page-3/

What a great resource! Thank you susu, I really appreciate it

Less is more ...
Add Circle 8 sides
(Rotate R 22.5, Extrude E, Scale S, Copy Shift+D, move and scale down, select 4 vertices press F ...

Add Subdivision Surface Modifier
Select edges you want keep as Sharp Edges Shift+E press 1

... here topology version for Quad Evangelists :)

Add thickness - you can simply select all and Extrude or use Solidify Mofifier. For more natural look of edges try Bevel Modifier

Note:
in some cases you can also use Bezier Curve with very similar workflow of creation - start from circle, duplicate, scale, extrude or connect points. You dont even have to manipulate with handles, you just select few of them and switch handle type V to Vector that automatically switch direction to point of a next control point.

For extrusion and bevelling edge use Properties Editor > Object Data > Geometry > Extrude and Bevel > Depth.
But keep in mind model can't be unwrapped, but it doen't has to be a deal in some cases with pointiness and other procedural material nodes.

in other words: add detail only where is needed.

Oh wow thank you for the help! From what I saw only I should avoid tri-gons, are they ok to have sometimes? Thank you so much

That is why I added one version without tris. I'm not an expert, but if you are not experiencing any shading or overlapping issue on surface, tris are OK as well. All game industry and even renderes triangulates mesh before they start to render, so there is too much emotions about that :)

@vklidu I hope you don't mind me asking another question. I just don't want to form bad habits. :) When beginning the second part of the arm where to second circle ends. Should I create a separate object and merge the two together after or extrude the circle and work from there? Thank you so much, you have been really helpful. A better picture of the second part

There is not an one correct way :) You can go both ways, for more complex models it is easier to separate into objects so you can hide quicker than hiding vertices, but your model is quite simple. But definetely dont connect vertices of pieces that suppose to be free. Also consider if you plan to rig your robot :)

Just did it! I was nervous about posting a question but now I'm not so much anymore. Thanks for all the help :)

Though there is already an answer detailing the "proper" way to deal with mesh topology, I will present a different alternative using curves.
Add a curve>Circle.

Enter edit mode select all the control points, duplicate and move.

Duplicate and resize.

Select two control points and subdivide.

Move the new control point.

Subdivide more points, move and rotate until you have the shape you need.

Exit edit mode, make the curve a 2D curve and set the fill to Both (so that it is filled top and bottom)

Give it some extrusion and bevel.


text:
How to simulate lowpoly hair motion in wind

all the tutorials I found were just flags

Somewhat related.  https://blender.stackexchange.com/questions/97408/how-to-get-wind-to-affect-hair-particles-with-group-or-object-render   I find google is a good search engine.  This search https://www.google.com/search?q=blender+hair+wind+tutorial came up with a number of other relevant links.

For low poly hairs object ...

go to Weight Paint mode and draw Gradient (from red on top)
Physics Properties enable Cloth

add Wind effector Strength 1000

select Head go to Physics Properties enable Collision
(better result with Self Collision enabled)


text:
Artefacts in topology of imported SVG
I've exported design from Illustrator to Inkscape to turn it in SVG and then make a model in blender. I've traced bitmap in Inkscape and everything seemed fine but when I click edit mode in blender - object appears with strange artefacts in topology coming from holes of an object. How do I fix this?

I've tried to voxel remesh as well but objects becomes too small and nothing really changes.

No problem save svg directly from Illustrator. For this shape you can keep object as curve object instead of converting to mesh. Than adjust Depth in curve properties. Probably if you can share your blend via https://blend-exchange.giantcowfilms.com/

@vklidu There it is, hope you will find a way to sort this, because when I paste it later to substance painter/keyshot - there's a complete mess with a model.

For a simple shape like that just delete all of the faces, keep the outer edges, and re-create them in blender using proper modeling techniques.

If object has mostly straight angles that need to be traced:

Create curve->Right click->Set spline type->Poly-> Just keep clicking E to extrude individual points. Because Object itself consists mostly of straight angles, its easier to do that.

If object need to have round angles in the end model:

Create curve->Right click->Set spline type->Poly-> Just keep clicking E to extrude individual points->CTRL+SHIFT+B on vertices in edit mode for accessing vertices bevelling.

Overlapping or intersecting paths in SVG do not translate well to blender, as they end up being different planes on top of each other. In the vector editing software use boolean operations (union, difference, intersect, exclusion, etc.) to clean up. those overlaps. Then export as SVG and import to blender.
See Complex SVG file fails to import correctly into Blender


text:
Merge objects in softbody simulation
I have joined the objects but they just won't hold together. In the first image, it's as it should be and on the second once it hits the ground, the objects get separated.

Can you show some of your settings please?  How did you join the objects?

Selected the objects (The head, foots, torso etc) and then ctrl + j

Here is the link: https://blend-exchange.com/b/5aV0NSMZ/   This is without doing what you said, didn't really understand...

It only selected just a part...

You have joined cubes into one object, but in Edit mode vertices are not merged.
Hower with a cursor above a vertex and hit L (Select Linked) ...

your mesh is selected partly - means vertices are not connected. This is the reason why it falls as separated.

it should behave like this ... I used Remesh modifier > Blocks to quickly generate merged cubes at similar density like yours ...

BTW - Your topology is too uneven and dense.
Wire density has essential impact on simulation result.

With the same Softbody setup, but low poly resolution ...

Here after Limited Disolve X operator ...

Note: You have to Apply Remesh modifier before simulation, because Softbody sim is calculated first and Remesh after - so it wouldn't be taken into a count in simulation.

But how do I connect them like that? In the easiest way?

Like I wrote - Remesh modifier

Sorry missed that. Could you send the file after the remesh modifier? Since mine still is messed up after adding blocks. It looks very weird and in edit mode, it still doesn't behave like yours...

Here is the blend https://blend-exchange.com/b/lMrKnrAq/ but as you can see in examples none of this version gives you desired result. I just wanted to answer your Q - Why it fails separated and show how topo matters. How to get proper sim with such object with details like tail or eyes, would be better ask a new one if needed.

How do I get back the material? Thanks for all the help btw!

By remeshing you lost UVmaps. You would have to unwrap from scratch. But before I would suggest to solve topology of your mesh. Remeshing was a dirty way to get quickly compact mesh based on your very messy and imprecise work. Minecraft is great for its precise cubic grid that you totally destroyed, sorry. BTW another way can be create a "dummy" (proxy mesh) with simple topology used for soft-body sim and "Mesh Deform" modifier for your original mesh using dummy object as deformer.

Did you download texture and build your mesh? Or there was a mesh delivered with texture?

there was a mesh delivered with texture, from mcprep.

I'm going for something like this: https://www.youtube.com/watch?v=qSBz7EAs0bU Another question how do I make it high poly again?

Comments are not allowed to use for chatting. Please create a new question (with description what you tried and didnt work for you) Try to search similar question if already asked. Thank you


text:
How could I run a Rigid Body simulation backwards after it is baked?
How could I take a Rigid Body simulation (it doesn't matter if it is already baked or not) and reverse it before rendering.
I do not mean reversing the clip after it is rendered (mentioned here).
I want accurate motion blur, because I am running another physics simulation at the same time that I want running "forward".

Hi, so, actually your question is a bit confusing, so could please add a few more details for more clarity?

@Aster17 What do you have trouble understanding about it? I am trying to bake a physics simulation and then have it play backwards, or just bake it backwards. I do not want to render the clip without the reverse and then use the blender video editor and reverse it.

https://blender.stackexchange.com/questions/95633/how-to-reverse-all-animations-physics-and-simulations#:~:text=In%20the%20Render%20tab%2C%20scroll,Go%20to%20the%20VSE.&text=In%20the%20VSE's%20Properties%20panel,make%20sure%20Reverse%20is%20checked. would this help?

@bblox have you tried something like setting the start time as the end time and the end time as the start time. Something like start time 250 and end time 1?

Option 1
For Rigid Body sim you can try  ... Bake simulation and with object selected search for Bake Action > enable Visual Keying ... it converts cache into keyframed animation.

Now if yo go to Graph editor and move timeline into a middle frame of your anim, you can Mirror curves Ctrl+M Over Current Frame ... results as reverted animation.

Option 2
Another option can be Export as Alembic (.abc) and Import back ... under Constraints Properties you can animate Override frame value backwards - at frame 1 set value of end frame and on last frame keyframe value of 1 ...

Mentioned here

Using Blender 3.0, in order to reverse the physics animation I had to do this :

Like Option 1 of the above vklidu's answer : with object selected > Layout (in object mode) > Object > Animation > Bake Action (with Enable Visual Keying)
Open Dope sheet mode
Select the object new baked keyframes you want to reverse (the selected keyframes color turn from white to orange)
Right click > Copy or Ctrl + C
Move the timeline frame cursor to the frame you want then Right click + paste or Ctrl + V
The new pasted keyframes should appeared, and they are now the selected (orange) ones > Move the timeline frame cursor in the middle of your selected new keyframes
Ctrl + M (Opens a dialog entitled Mirror keys) > By times over current frame
IMPORTANT last but not least : In the physics properties of your object > Rigid body > Settings > check Animated (because if not: you might never see the result of it all !) ... You can also only make it animated only for this part by "keyframing" this checkbox as it is possible.

Hope it'll help :)


text:
Robust way to translate animation temporarily, including particules/quick explode
How can I robustly move an animation temporarily? When I move the keyframes in the dopesheet, it won't move for instance the particle frame start/end. For instance, I just selected the cube and did "Object > Quick effect > Quick explode", and nothing appears in the dopesheet:

If it's impossible, is there a workflow that would allow me to solve maybe differently this issue? I guess translating animations is quite common as people rarely know in advance which timing they exactly want...

@martyfouts: thanks. I'm not used to baking simulations, can you then choose the starting time of included simulation using keyframes? Or do you mean you completely render them in a different project and integrate them in post production? Concerning the drivers, I asked before if it was possible to "drive" a field into a keyframe, but I found no answers, so if you know how to do I'm interested. If you mean to add a driver to another variable, like a custom property, then the benefit is not clear, except maybe to centralize these parameters...

I deleted all my comments ... there is not an option to set driver or keyframe this value ... that make a sence since variable here will generate mishmatch ... so - no I dont think there is a native way in Blender to solve it. So ... as written before you would have to bake sim to by able namipulate on timeline.