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How to limit the stretching amount on a cloth rope, instead of allowing infinite elongation
I have the following scenario (see picture):

A rope is modelled as a group of vertex, with a skin and subdivision modifiers.
This rope is hanging from a top plane and it's configured as Cloth.
Its Upper end is hooked to an Empty, which is parented (Keeping transforms) to the top plane
Its lower end is hooked to another Empty, which is parented (Keeping transforms) to an active Rigid body, supported on top of another passive rigid body.
The active rigid body and its supporting passive rigid body are constrained by means of another Empty with a Hinge relationship.
As the Center of Gravity of the main object lies to the left of the Hinge axis, when playing the animation it starts falling (rotating around the hinge) while keeping the connection with the rope, which extends as much as it might be requested without any limitation.

I want to limit the amount of stretching that the rope could stand, so that it does not allow for a complete revolution, but it only falls a few degrees and holds the main object.
I tried playing with all Cloth parameters without any success. I also searched all previously asked questions but I'm unable to find a working solution.
Could anyone provide some guidance?
Thanks a lot in advance

After doing some more research, I just realized that Rigid Body and Cloth simulations do not interact too much, so I came up with a workaround which is to create an additional "General Spring constraint" in between the main object (active) and the top plane (passive), and activate all angular and linear axes. By means of this constraint, the amount of turn around the hinge gets constrained and it fakes a limited stretching on the cloth rope. Now it's a matter of playing with the spring settings so that it becomes more realistic.


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How to simulate Planet orbits with Rigid Bodies
I've done the typical simulation of Sun/Earth/Moon orbiting each other by using the "Follow Path" constraint, which is simple after watching a few tutorials.
But then I asked myself if I could do the same by using Rigid Bodies simulation only.
So I created a Motor and a Hinge RB-constraint in between Sun & Earth, allowing the Earth to orbit around the sun, and I did the same in between Earth and Moon, but parenting the empties for these 2 constraints with the Earth, just to make sure that they travel along Earth's orbit.
Surprisingly, the Earth's rotation is 'irregular' (goes back and forth) instead of having a constant movement around the Sun.
Can anyone suggest what's wrong with this scenario?
Thanks a lot in advance!!

Not surprisingly, this is indeed how planets orbit. The moon "does" make the Earth wobble, the difference is that there is a greater difference in mass, so the Earth's wobbling is little. What is actually wrong there is the "hinge" that is not allowing the earth to wobble in the radial direction of the sun. A real simulation would need radial fields of "acceleration" with quadratic falloff, each field at the center of each object. --- But to fix your simulation, decrease the moon's mass or increase the earths mass, or both

Thanks a lot @DanielMöller, actually by playing with Earth & Moon's masses and motor speeds too, I can get a much more fluent movement. But I was not intending to create a fully realistic simulation (in fact orbits are circles and the 3 bodies are on the same flat level, without any axis deviation), instead I just wanted to learn if the 2 motors could act independently. What I've learnt is that rigid bodies do consider all masses and distances, so probably this is not the best way to generate independent movements in the animation, but the "Follow Path" constraint is the way forward.

source: Stack Exchange

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

sort: votes


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White box Artifact appearing in render?
I am new to blender, and while I was following this blender tutorial: https://youtu.be/y0DMMwwdBaY
At the 15-minute mark, we start using the compositing tab. For some reason, using this tab causes a white box to appear in my rendered image which does not show in the camera view.
Does anybody know how I can fix this?
Compositing view render:

Camera view render:

could you attach your .blend file or compositing setup

After some investigation, I found the problem, and since I can't figure out how to delete the post I'll just put this here:
The issue turned out to be a very small object mesh that I had set to invisible that was showing up in a buggy fashion in the render. since I had not done so until the compositing step, I mistook this as the cause. Deleting this hidden mesh fixed it.

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


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Objects in a scene have their own light
I'm working on an ambitious project, using a lot of tools and features I've never used before.
I'm nearing the end and I'm trying to figure out my lighting. I watched some videos on lighting in blender but for some reason my objects, the axes, are not being affected much by the light sources I add. In fact they seems to be their own independent light source in both Eevee and Cycles. I've turned the entire background black and yet they still remain visible in the render preview. They don't have an emission tied to them. They are using nodes for image texture, subsurface scattering, color ramp, and mix shader.
I know I've made a few mistakes during this process but I have no idea what is causing them to be lit like this.

have you tried adding an HDRI ?

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

Are your nodes connected through a shader (BSDF), or are they connected directly to the material output? That looks like un-shaded outputs to me.

Welcome, have you tried to increase the power of the lights? Something like this?

Sometimes, if the scene is big, more power is needed. Also, clicking on the Preview helps in determining the light strength. HTH

Here's 3 things to try:
1. Turn the World Strength to 0.
In the World tab in the Properties panel (or in your Background Node in the World node editor), set the Strength to 0 instead of 5.
2. Make sure ALL lights are deleted/hidden.
You can press H to temporarily hide an object.
3. Be sure that your models are not using Emission shaders.
Emission shaders are a type of shader that acts as a light source. Check that you're not using any Emission nodes in your materials.


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Is it possible to exactly set a UV mapping by entering the UV values as numbers instead of clicking and dragging?
I'm trying to apply a UV texture I created to a model, but I'm not satisfied by the level of precision offered by simply clicking and dragging with the mouse. I would like to be able to pick a vertex and enter by hand the specific, exact UV values I want (like [0,192]) instead of "close enough" freehanding with a mouse. Is there a way to do this?
Failing this, is there a "snap to grid" feature so that the mouse will snap to exact multiples of some value such as 32px?

I actually just figured it out.
Select the specific vertex in the UV editor and press the N key. That will open a panel on the side where you can type the exact UV coordinates. They are as a percentage of the image as opposed to exact pixel numbers (for example, 64px on a 512px texture is 0.125) but doing the math is no problem, especially as you can enter the math (like 64/512) right there in the input field.

ah yeah i remember having the similar issue here https://blender.stackexchange.com/questions/255810/how-do-you-set-the-x-y-and-width-height-in-pixels-of-uv-islands


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Weight painting doesn't seem to affect model in pose mode
I'm having trouble rigging this character. I have it weight painted (seemingly) properly, but I still get the stretched mesh when trying to pose.

I think you started out wrong. I don't think you want the (supposedly metal) parts of your robot to bend and deform. The way you usually do mechanical rigging is parenting the moving parts to the bone instead of weight painting if they are separate objects. Or if you have all parts in one object, parent it to the armature With Empty Groups, then in Edit Mode, select the group with the name of a bone, select all vertices of the mesh that should be controlled by the bone, make sure Weight below the vertex groups is set to 1 and click assign. Do that for the other vertex groups as well.

To add to Gordon's post, if you really want your object to deform, activate the On Cage and Edit Mode options of your Armature modifier, select the vertices that are not correctly assigned, and assign them to the good vertex group in the Object Data > Vertex Groups list

thank you both! this solved my problem :)


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Annotation vs Grease Pencil
I'm new to Blender (2.9), just getting through the docs, and also new to animation.

An annotation is extra information associated with a particular point in a document or other piece of information. –Wikipedia

It seems like Grease Pencil can do everything that Annotation can, and more, and I'm hoping for some insight as to the role and practical usage of Annotation, as opposed to Grease Pencil.

since 2.8 annotation has mostly become a way to write some informations, like a post-it, while grease pencil is made to create 2D animations

The main difference is that annotations are meant to be notes, or sketches for reference only. There is no way to render them and cannot be animated.
Grease pencil objects are renderable, and can be animated. They are designed as a "hand drawn" animation tool in a 3D environment.

When you create an Annotation , it is used to be used as a reference , for example you can use to annotate a bad geometry in object mode and then go to wireframe mode fr solving that problem still knowing where it is because to annotated it .On the other side , you can use Grease pencil to make 2d animations in the Blender 2d preset and also to serve the same purpose as annotations , but the annotations doesn't have the features grease pencil like size materials and others.


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How to set non color to node in shading in aces color space?

Can`t find non color setting to roughness, normal map textures in aces color space.

ACES has some shitty labels. Utility - Raw or Role - Data.

lol ACES doesn't have shitty labels. Those are industry standard labels that Blender should have adopted. They are aligned between many disciplines. Utility-Raw is raw data, aka no color conversions applied, aka what blender refers to as Non-Color.


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How would I add ridges to this mesh?
So I'm trying to model a rocket engine, and I'm trying to figure out how to add ridges to the nozzle.
This is what I currently have:
And this is what I'm trying to achieve (specifically the ridges on the nozzle itself):

So how would I go about this? Thanks in advance!

do you mean the parallel circles all around it?

Yes! I can't figure out how to do them without making a mess out of it all :S

it looks like it's another object, so you could duplicate your current object, create additional edge loops, only keep these edge loops, extrude to give them thickness, give it Subdivision Surface modifier to smooth

I just wanted to add to moonboots tip, which i think is good but i think can be a little clearer : )
1)
Select you object in Edit Mode. Use Ctrl + R to add edge loops (mouse wheel to increase/decrese the number of edge loops). Then mouse click, slide (if needed), and click again to confirm. If you put two edge loops close to each other you have a loop of faces, which can be the basis for your ridge.
Alt + mouse click a face in the loop to select the whole loop. (if it selects faces in a perpendicular direction, click closer to another edge of the face)
With your faces-loop selected, press Alt + E and choose Extrude Faces Along Normals, and extrude the ridge.
Instead of a Subdivision Surface modifier (that moonboots proposed) i would use an Edge Split Modifier, since I believe the section of the ridges on such a nozzle is square. An Edge Split Modifier will help pronounce this while the rest of the nozzle stays smooth.
2)
Alternatively you can Alt + mouse click a single edge loop. The press Ctrl + D to duplicate it. Press P to Separate By Selection.
Select the new edge loop object in Object mode. Press Alt C to Convert, and choose Curve from Mesh/Text.
Then go to Properties > Object Data Properties > Bevel, and set the Depth to some thing more that 0, and set the Resolution to 0.
Finally go to edit mode, select all the vertices, press Ctrl + T to rotate or tilt the vertices 45 degrees.
This way you can give all the ridges the same section size by giving them the same Bevel Depth value.


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Volume Scatter in Cycles Turning world black
I am working on creating a sunset and am having trouble getting the volume scatter node to not turn the entire world black. I have already tried numerous suggestions from other posts including checking that my light source is not a sun-light, checking that the light's power was high enough, and that I have plugged the volume shader into the volume, not the surface input. Despite this, the volume scatter turns the world black. Interestingly, it does this if the density is anything but 0 (e.g. 1.0 ^ 10^-7 still gives a black world).

I have attempted to use a cube encompassing the scene as well, however I have been unable to make that work. Nevertheless, on a matter of principle, I'd like to get this to work because I can do it in a normal scene without the rest of my objects in it, it is something in this specific file preventing it from working.

You can't use volume and surface simultaneously in the world. Use a mesh that surrounds the scene and have that one have the volume.

Read: https://blender.stackexchange.com/questions/49893/rendering-environment-pass-without-combined-pass-in-cycles and https://blender.stackexchange.com/questions/19217/why-doesnt-an-environment-texture-appear-when-the-world-has-a-volume-scatter-sh


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How to rotate a procedural texture on a single object?
When several objects share the same procedural material, how do you place it on an individual object the way you want to?
For example, how do you rotate the texture on one object, but not on other objects with the same material?
For image-based textures, the answer is simple: you can edit each objects's UV-coordinates. But how do you do it for procedural textures?
I know you can rotate procedural textures by using a mapping node, but that causes the texture to rotate on all objects, not just a single one:

I'm sure that must be a simple solution for this. I can't imagine you'd need to make a seperate material for each individual object.

I would rotate the object's UVs instead.

But a procedural material doesn't use UV coordinates, right?
A procedural material is 3D, not 2D.

A possibility, use object index and define the rotation you want depending on it.

of course they do except in case you mean generated UVs (object UVs)

The solution is to make a separate material for each object (or set of objects that share the same properties) - as that allows you to adjust it for each object. However, it's not that you need to replicate the whole material and can't share sets of nodes, since you can create a Node Group that contains most of your material and re-use that group within each seaptarate material - maybe just adding a Texture Coordinate and Mapping node to each one so as to allow the orientation and scaling to be adjusted.

Later I found out that you can scale/move a texture on a per-object basis by choosing:
Object --> Transform --> Move Texture Space, or
Object --> Transform --> Scale Texture Space.
Unfortunately, there is no Rotate Texture Space option, so I will consider the answer above to be the official one.

@Frank This is a hot tip, though.  I think it deserves to be in an answer.

I've run into a similar problem trying to create a wooden arch constructed from straight segments of wood.  Originally, the procedural texture just maps across all of the segments uniformly, i.e. the wood grain ignores the orientation of the segments.
My workaround has been to  rotate the segments so that they align with the procedural grain. Apply the rotation, then reapply the procedural texture, and rotate back into place.


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Why don't my tracking markers stay in position?
This is my very first post here. After having used it a few times in the past, I recently started playing around with Blender again. At the moment I'm experimenting with Blender's camera tracking feature, and I keep running into an issue that I'm unable to solve.
The problem is that the markers of tracks don't stay in the position I put them in.
For example, when I place the marker in the first few frames of my video footage (either manually or by clicking the Track Markers button for automatically tracking a single frame) everything looks fine when I play the first few seconds of the video: the marker perfectly follows the item in the footage that I'm trying to track.
But when I continue to work on the same track, and move the marker in another part of the video (for example, around frame 532), and then go back to the first few frames, the marker has shifted to a different position there.
Example:
I manually placed the marker in the right position in frame 17:

After manually moving the marker in a few frames around frame 532, the marker in frame 17 looks like this:

NOTE: In this example, I didn't press any Tracking button. All the changes to the marker position were done manually.
How is this possible? Is this a bug in Blender, or did I accidentally activate a setting that causes changes in frame x to influence the position of the marker in frame y?
I'm using Blender 2.90.1, and my tracking settings look like this:

Any help would be much appreciated!
Kind regards,
Frank

I found the solution myself.
For some reason, the frame numbers of my video file didn't stay in synch with the frame numbers of the track markers: when I would scroll to frame n in the timeline, it would sometimes show frame n+1 of the video, making it look like the marker had shifted.
I solved the issue by converting the video to separate image files before importing it in Blender.

Never use "for some reason"... The reason is that the video is using long GOP compression, not intraframe Read: https://blender.stackexchange.com/questions/185251/render-is-duplicating-random-frames-when-loaded-into-3d-tracker/185253#185253 and https://blender.stackexchange.com/questions/53510/vse-problem-blurring-license-plate-mask-is-jumping-all-over-video/53514#53514 and https://blender.stackexchange.com/questions/195339/movie-recorded-on-phone-reports-inconsistent-number-of-frames-when-imported-to-b/195341#195341

and https://blender.stackexchange.com/questions/162362/is-it-required-converting-videos-to-an-image-sequence-before-doing-motion-tracki/162364#162364


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How to make Filmic view transform to not affect the background image?
When rendering 3d scenes, I use the default view transform Filmic, because it is said this gives the most photorealistic results.
But when I composit 3d elements over a background video, the Filmic view transform also affects the video footage. I don't want this, because it makes the colors in the video look less saturated.
What would be the easiest way to keep the original colors of the background video, while applying the Filmic view transform on the 3d elements?
Do I need to save the rendered 3d scene to a file before doing the compositing, or is there a way to do rendering and compositing in one go?

Also worth reading if you are using filmic built into blender...

Thanks, I will read that!

Preamble
Just to understand why we are mixing apples and oranges and what the problem is.
In blender, images are rendered in scene referred values, meaning the data is linear and the values unbound (in an infinite scale). Such information needs to be processed through color transforms (set in the color management section) to be viewable in a display (a monitor, projector or print). Displays use a very limited scale of values (black is at 0 and white is 1) and require a transfer function (sometimes called "gamma curve"). In other words the color transforms, filmic is one of them, convert scene referred data to display referred.
The math for Compositing images works best with linear information, in an unbound scale, in other words: scene referred images are better suited for compositing.
Video images are usually recorded in a display referred format. In a limited scale and with a baked in transfer function.
It is hard to mix scene referred images with display referred images. It is a lot easier to mix them if they are in a common scale.
Unfortunately, Blender's compositor is quite limited, in the sense that has no tools to deal with images trough different paths for color processing.
A couple of options
There are couple of ways to approach the problem.

Best case scenario: Video in Raw or Log.
If the video is shot with a real camera, one that can record the raw info or using log encoding. The advantage of such formats is that they can record a lot more information and dynamic range in a way that is the images can be converted to scene referred linear values quite easy. Then all you need store them as EXR (this can be done in DaVinci resolve or other software).
Then use the EXRs in blender (or any other compositing app like Nuke, Fusion, Natron) and composite CG renders and Video images happily ever after.
Alternatively you might choose to keep the images in a log encoded format and de-log (linearize) in blender or whatever other compositing software you use.

Video not in Log or Raw.
Most video shot with consumer cameras (DSLRs or phone cameras) is recorded in a display referred format.
It is very hard to accurately convert such images to scene referred values. The difficulty lies in the way the cameras convert the values from the sensor in a non-linear way. There is no easy way to undo or reverse such conversion and restore the values of the light that was registered by the sensor. The curves used to fit the light values into the display referred container are not reversible.
The only possible way to mix those images with the cg in the realm of display referred imagery... So render in blender with filmic with no background and composite later. If you do this in blender remember to set the color management back to sRGB (also called "standard" or "default") so that both images are decoded and encoded using similar values.

Thanks for this quick and extensive answer!

If this answer helps a lot, please consider to upvote @Frank


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running blender python script outside blender
I'm doing a project, and I use blender to set up a scene (mainly I have two plane meshes) and with scripting I do some operations on the meshes. I installed blender as a python module using conda env and it worked(I can import bpy), but it throws an error that my object doesn't exist, it looks like it can't load the scene from the .blend file
I'm trying to run a blender python script without having to install blender, is it possible?

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.

right now I have a code that I run from blender which means I open the GUI and run the script. the company that I work for want to use this code on servers and they don't want to install blender on their servers. how can I do this? I use pycharm and I managed to import bpy but when I run the code I got an error that the objects I'm trying to modify do not exist even though they do exist in the .blend file. to import bpy in pycharm I used  "conda install -c kitsune.one python-blender" (after creating a conda env)

Actually much of the python code that depends on the bpy classes are then calling into the blender core application code, so you won't be able to run without blender installed.   Even a bpy.ops.wm.open_mainfile will throw an error, should you manage to get the bpy python files installed on the server.

All answers are in the question that I've shared, aren't they? The module section that I haven't heard about describes a special built of blender, that can be run as a module. I'm not sure that it is a feasible task. So the easier way to do this is to run blender from cmd or python blender --background --python myscript.py

You don't have to install blender to run it. You just download whatever blender build you want to use and run the compiled .exe in the download folder. answer that @Crantisz should work in combination with running the blender.exe from it's location on the server.

Well, I'm not sure, @Jakemoyo. I prefer installing blender properly because it may require additional dependencies on Linux server.

I run blender on Linux, I download daily builds all the time and it doesn't require any dependencies, other than what someone could manually add to the blender/3.xx/scripts/addons folder. I just set a symlink in /usr/bin/local to whatever .exe is the latest version I want it to point at. The answer you posted should work.

it worked but I have to download the whole builder. now my question is do I need the whole builder folder?


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Alternative to Bendy Bones for gltf/glb export
I'm trying to export the following rig to use in three.js:

The goal is to have it move on two axis like this:

As you can see, the Base cube is connected to the upper part of the mesh via a tube, which is rigged with a bendy bone, that is a child of the upper part of the mesh. This sollution works fine in Blender but the problem is, that gltf doesn't support bendy bones, so I'm looking for a simple alternative. The goal is to use the model in a three.js application.

maybe create a chain of bones and give an IK constraint to the top one?

@moonboots I'm actually not sure if three.js supports IK rigs

if this is for pre-made animation, there's an Auto IK option that allows you to animate as if the bone had IK, or you can bake the animation

@moonboots unfortunately it isn't for a pre-made animation, in that case I'd just bake it. It is for a web application where the user should be able to rotate the mesh along the two axis

three.js can be used with IK rigs (see https://github.com/jsantell/THREE.IK), but I don't think there's any off-the-shelf workflow to export an IK rig from Blender to three.js. You'd need to set the IK rig up again in three.js.


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Final render keeps smoothing hard eyes
I'm new in blender and I'm sure this is something really easy to fix but after looking for solutions I couldn't find any.
I have this models with hard edges but when I do the final render they get smoothed and more rounded, how can I turn off that so that in keeps looking like in the first image?
Thank you so much!

You have a subsurf modifier with different levels applied in the Viewport and Render.
Viewport:

Render:

This, or (since the viewport doesn't look very rounded at all) there is a Subdivision Surface modifier simply turned off in the viewport and only showing in render.

That was it! Thank you both so much. You were so quick!!

No worries, can you mark the answer as accepted?

done! thanks yo so much


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There doesn't seem to be any way to automatically make 'Left' and 'Right' vertex groups. Does anyone have any tips or work arounds for this?
I'm modelling a human body using python code in blender. The way I'm doing it right now, I start with half a cube that has a mirror modifier on it and work from there. I'm adding vertex groups for body parts like the chest or the shoulders. For body parts that come in pairs, like the shoulders, I would want to make two separate vertex groups, one for the left shoulder and one for the right. Is there any way to quickly do this besides just creating them and assigning them after I apply the mirror modifier?

If the vertex groups follow a proper naming convention and exist, the weights can be automatically mirrored by the mirror modifier.

OOOOHHHH! Thanks a ton, this is exactly correct.


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How to clear animation data from a premade model?
I have purchased a riggend and animated model off the internet (link to model) and I want to clear the data animation on it and just create my own animatio. I have tried to clear the animation data on the object, but only the skeleton loses the animation and the mesh keeps running the animation (if does not follow the skeleton anymore).
Before clearing animation data:

After clearing animation data:

I have tried importing the object and its data into another blender project and I have been able to animate it this way, but there are some particles and details in the main project that I can't transfer, so this is why I'm looking for a way to modify the main blender file.

One way to do this:

Switch to the Dope Sheet (Shortcut: Shift–F12  You may have to type it twice to get the Dope Sheet rather than the Timeline)

Make sure that this group of icons on the right looks like this:

That is, from left to right,

disable "Only Show Selected"
enable "Show Hidden"
disable "Only Show Errors"

Hover over the main window

Select All (shortcut A)

Type X to bring up the delete menu and select Delete Keyframes

To return to the 3D viewport use Shift–F5

That should remove all animations, unless you have some baked physics.

Thank you! The main problem was the baked physics that I managed to get rid of after unbaking it.


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Why does the Alpha Over node make my image brighter?
In a Cycles project in Blender 2.9, I want all objects to receive white light from the environment, so I set World Properties --> Surface --> Color to white.
But I want the background of the final result to be dark blue, so I checked Render Properties --> Film --> Transparent, and use an Alpha Over node in the compositor to get my blue background.
This is the original rendered image with a transparent background:

And this is the picture with the blue background composited in:

As you can see, the Alpha Over mode makes the image much brighter. But I don't want that: I just want the original image with a blue background.
What I tried:

Checking "Convert Premul" (should not be needed, because the rendered image already contains a premultiplied alpha channel)
Manually changing "Fac" (which has an unexpected behaviour: it takes an extremely low value (0.0001) to make the foreground transparent. I expected the foreground to be 50% transparent at Fac = 0.5)
Connect the Alpha output of the Render Layers node to the Fac input of the Alpha Over node (should not be needed, because the alpha channel should already be in the picture itself)
Setting the brightness of the Sun lamp that is also in my scene, to 0.
All of this did not solve my problem.

My question: How do I get the rendered image in front of a blue background, without making the rendered image brighter?
Any help is much appreciated!

One thing you could do to reduce the overblown brightness in the semi-transparent parts is using the Alpha Convert Node in the Compositor. Put it between the Render Layers and the Alpha Over and set it to "Straight to Premul". This reduces the brightness in transparent areas a lot.
The transparency in the render still won't look like the transparency in the Viewer Node.
To get that result you need to clamp the image's RGB values, for example by using a Color > Mix node with Clamp enabled. Then you can multiply the image with pure white or add pure black and then the output has all bright pixels clamped to white and the alpha transparency works on that. The thing is, if you want that, why is the brightness so high anyway?
Although you said, you set the strength of the Sun Lamp to 0 and even that didn't change much, the file you provided had a sun with a strength of 1000. In Blender, a sun even with only a strength of 10 is very bright.
So rendering your file with the cube and a sun of 1000 resulted in semi-transparent areas around the cube, which had RGB values above 150 or even 200 at a transparency of 60%-80%, which gives pixels far beyond white. And that's why everything is so much more bright then in the Backdrop view.
You should set the sun way lower to get the result you want. If your objects look grey instead of white and that's why you cranked up the sun value, try setting View Transform > Standard instead of Filmic in the Color Management.

Thanks for your reply!
I simplified the scene to only 1 cube. You can find the blend-file here: https://www.mediafire.com/file/da5tym8hl4ur38g/Alpha_over_node_makes_objects_far_from_camera_brighter.blend/file
I found out that the issue happens when an object is far away from the camera, and only consists of a few pixels in the render. But why? The compositor doesn't know that this is an objects far away. It should only see the individual pixels, and treat them all the same way, right?

I tried your alternative solution, bit it had exactly the same result (as least, visually) as the Alpha Over node solution.
In both solutions, pixels near the border between opaque and transparent pixels are made brighter.

I'll have a look tomorrow when I'm at the right computer. I already feared it might happen with my workaround, too. Anyway, maybe we can find it out.

You wrote in the question, you've set the Sun Lamp to 0 and it didn't change anything. I've downloaded the file and at least there the sun has a strength of 1000 - for a sun lamp as light source even 10 is already a high value. Especially when the World is already lightening up the scene with white color at a strength of 1. After rendering, right-clicking the cube results in RGB values above 200, which means even in the half-transparent borders they are far above 1. The white of the cube is fully blown. It got a little bit better when I've set the Premul slider to 1.

Thanks for your answer. I will make the sun less bright.

But can you explain why the superbright pixels (way beyond white) become even brighter by using the Alpha Over node? And is there a way to turn the superbright pixels into normal RGB values before performing the Alpha Over? I thought the Filmic "filter" is applied at the end of the node chain, not at the start. So the input of the Alpha Over node would still be ultrabright.

They don't become brighter. It's the Image Editor not capable of showing them correctly. If you render the image and leave the background transparent, they are shown clipped to white at 1 and then multiplied with the alpha value which makes them less then 1 in semi-transparent areas. But if you right-click some of these pixels, the RGB values are still displayed as beyond white. When you put a background behind them, Blender calculates the "real" mix values. So, e.g. a value of 0.1 at 100% opacity overplayed by 60% opacity of 150 is 0.1 + 90 = 90.1, which is clipped to 1 at 100% opacity.

The Filmic transfirm is not applied at the start, and it doesn't make the pixels brighter. Since it has wider dynamic range, values must go beyond white to not appear light grey. I just mentioned because I was wondering why would someone crank up the sun to 1000? What you could do get the image less bright: make the sun much darker or even delete it. Or if it has to be like that, reduce the color range.

For example, plug the image into a Seperate RGBA node,  plug the R, G and B each into a Map Range node with Output Min/Max set to 0/1. Set Input Min to 0 and Input Max to 5 or what looks good. Then Combine RGBA and plug the image output into the second socket of a Color > Mix RGB node with dark blue as the first color. Use the Alpha Channel as the Mix Factor.

Thanks! I learned a lot again.

I've edited the answer (again) because I completely forgot about the Alpha Convert Node. With that, some of the overpowering white gets reduced, but it's still not the same as the Backdrop in the Compositor. To (more or less) achieve that look, I've provided a clamp method as well. But all this results in reducing the brightness as you could have done before rendering.

Thanks for all your research / explanation. It's hard to understand how colors work in Blender, but it has become a little more clear for me. I guess the best solution for this particular problem is to give the sun lamp a normal strength.

You should never ever clamp values if you are using filmic (it kind of defeats the entire purpose of using a scene referred transformas that what a display referred transform is doing, clamping 0-1). Use the CDL node at the end of the node tree to correct the output with false color if needed to pull the blown out areas back to middle gray/ cyan. Your renders will be much better off.

@Timaroberts Of course you shouldn't clamp. It's just he was going to achieve the look of the Compositor Backdrop in the Render Result... and that's how you get it. Why he started out with such overly bright light in the first place I don't know, because for that result he might have gotten away with just the world lightening the scene.

Gordon, in one of your earlier answers you described an interesting alternative using a world light with colour x, but a background with color y (without using the compositor).
Unfortunately, I can't remember how you did it, and you deleted this solution from your answer. Where can I find the setting for the background color again?

Oh wait... it had something to do with the World Shader, and handling camera rays differently than non-camera rays... I think I can figure it out myself

You're right, that's it. Use the Is Camera Ray output of the Light Path node for mix factor.


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What's the difference between the Undistortion node and the "Render undistorted"option in the camera background settings?
When you do camera tracking in Blender and press the "Setup Tracking Scene button", Blender automatically sets up a compositing node configuration that makes is easy to add 3D elements to the video footage.
One of the nodes is an Undistortion node, that is supposed to undo the lens distortion, to make the undistorted 3D elements generated by Blender fit into the footage.
When you are working on your scene, you can set the video to be the background image for your camera. In the settings for the background image, by default the "Render undistorted" checkbox is checked.
My expectation was that this would have the same behaviour as the Undistortion node in the compositor, but this appears to not be the case.
In the camera background picture, the undistort-option makes the picture look worse than the original: a line that was originally pretty straight, looks bent after performing the undistortion.
In the compositor, the undistorted picture looks exactly the same as the original footage, as if Blender has decided that the original video was not distored at all, and doesn't need any undistortion treatment.
My question is: how is it possible that the Undistortion node has a different behaviour from the "Render undistorted" option for the camera background? Do they, for some reason use different distortion values (K1, K2) to do their calculations?

Today I found the answer to my own question.
I discovered that in the Undistortion node, you need to specify the movie clip that should be used to calculate the undistorted picture. It turned out that I was using an earlier version of my video there, instead of the version that was used for motion tracking.
Specifying the right video gives the expected result.

Thankyou for taking the time to come back and post an answer once you solved it for yourself - it makes the site better for everyone, so it's lovely to see it happening.

The camera background image in the viewport, with Render Undistorted option enabled,

should look the same as the result of the "undistort node" in the compositor,

and same as when you check the "render undistorted" in the Clip Display options in the Movie Clip editor.

In the undistorted image, straight lines should look straight, not curved. If they don't, then the Radial distortion coefficients k1, k2 (and k3) are not set correctly, or the optical center of the image might be incorrect as well.
To determine the distortion coefficients photograph a chart (or anything that has straight lines), open the image in the movie clip editor and use the annotation tool to trace thosestraight lines and distort them to match the image as shown in the following link:
How to determine lens undistortion values for motion tracking?

Thanks for your extensive answer. What could be the reason why I don't get the same results in compositor and background image? Are there different places where the K1, K2 and K3 numbers can be specified, or can you only do that in the Movie Clip Editor?

In the image you have two viewer nodes, make sure you are viewing the one that is connected to the undistort node.

I have 2 viewing nodes to make it easier to compare the pictures with and without distortion. When I switch between the two, the backdrop doesn't change.


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How to get the shell of a mesh?
I created an image in illustrator, which I have included here:

Note that the white space in this image is empty and is not a white color fill. I am importing this image as an SVG into illustrator. What I am trying to do is to take the tracing of this image, turn it into a mesh, and extrude it. However, whenever I import the image into blender, I get this:

Notice how the imported SVG fills in the shape instead of it just creating a tracing of this shape like I have created in illustrator. Is there any way for me to create a mesh where it is just the tracing of this image? Thanks in advance! Also let me know if I need to clarify.

It's the opposite question but you should be able to unfill your curve using the answer

Not really, I don't know much about bezier curves unfortunately

Select the object, navigate to the curve properties (green arc icon in the lower right of your screen) and look for a property called Fill Mode. Set it to None.

Result :

Hello! I think I understand how to do it now! Thank you! I am planning on extruding this as well. One question I do have - the stroke of the tracing I have above has a certain thickness - I was wondering if there was a way to emulate that instead of the curve just having an infinitesimally thin stroke?

Use another curve shaped as a rectangle as the bevel object of your own curve, so it will create a rectangular tube along your curve. Then you can set the size to the width you want.


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how to remove reflecting light on image imported as a plane?

I want light to reflect only for a model(not for an image imported as a plane)

hello, it depends what you call reflecting light, you can either use an Emission shader instead of a Diffuse, or lower down the specular value, but please tell a bit more

The Import Images as Planes file selection window has an extensive set of options in a panel on the right. You may have to press N to reveal it.
Here are a few of them. One of the material options is 'Shadeless':

.. which produces the desired characteristics. It does it by using an 'IAP_SHADELESS' group:

..which is worth a look, if you want to see how these things work.

Absolutely this is the best options. Thank you.

An Emission shader is propperly able to fix your problem. Here is how to do that:

Go into the shading window.

Delete the Principled BSDF shader.

Add an Emission shader.

Connect the shaders like on this image.

Now it should be working.


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Cloud rendering issue, Car is blurry and I can't figure out why
I am rendering this animation on garage farm as my m1 Mac is too slow. The animation renders fine on my computer but every time I upload it to a cloud render the car seems to disappear in a blur.
I have tried doing it with motion blur off, baking the animation, etc but it always comes out with a car that is ghosting in and out like a mist.
Any thoughts on how to fix this?

Would it be possible to upload a blend file? That might make it easier for us to track down the problem.

Sure thing, I put it in this google drive folder:
https://drive.google.com/drive/folders/1mv1cPerTqzOsIfn8889Xvc-bukU_qCA3?usp=sharing

Before rendering the full animation, do you try a single frame ?

it works fine for me except there's a glitch on the light of the car

It works fine in blender locally on my Mac, the issue only occurs when I try to render the animation by uploading it to a cloud render farm.
I have tried two different cloud rendering services and they all return the same warped animation. I do try single frame rendering and it shows me this ghosting effects in the single frames.
Moonboots, did you render it just on your computer?

yes on my computer


text:
the blue line of the timeline doesnt match with my current frame

The blue bar doesn't match with the blue line, and when I press play the blue line also goes in a very slow way
It's impossible for me to insert keyframes, because if I insert a 1s animation, it is actually longer than that.

In the Output panel, you must have played with the Dimensions > Time Remapping values (which are used to slow down or speed up the animation), bring them back to 100/100 for example:

+1 for obscurity :)

"obscurity"? what do you mean?

The problem is so unusual. It would have taken me ages to track it down :)

oh ok, but once you've used Time Remapping you'll remember that it desyncrhonizes the cursor with the line

Ahh, OK. I prefer messing about in the NLA.

Yes it's cleaner to do it through the dopesheet or graph editor but time remapping is faster and it allows to test some speed changes, plus sometimes you can't move some animations together

damn, you saved my ass, I just remember I adjusted it when I making some particles.thx!!!!!


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Nodes won't save?
I have a mesh of a person that I'm trying to put textures onto.  I have a diffuse, normal and micronormal texture to add.  Here's what nodes I've been using
MICRONORMAL - Texture coordinate>Vector Mapping>Image Texture>MixRGB (slot 1)>Normal map.
NORMAL - Image Texture>MixRGB (slot 2)>Normal map.
DIFFUSE - Image Texture>MixRGB (to alter skin tone)
Everything is then plugged into the appropriate slots on a Prinicpled BDSF node and finally to the Material Output node.  This worked fine last night
I then exported as an .fbx file. However, when I reload the file, there's no textures on anything.  Everything is just blank white and the only nodes remaining are the BDSF, Normal map and Output nodes.
I've tried adding a fake user to the textures and adding each node in manually, but they're still gone again when I reload the mesh.  Like I said above, I did the same last night for the body textures and it saved fine.
Can anyone tell me:

What I'm doing wrong and why the textures aren't saving?

How to copy and paste the nodes properly to save time, as that's what seemed to cause the problem to start.

Don't know if it's important, but extra info:
The mesh was created in Character Creator 3, so all the textures were saved to a folder when I exported the mesh from that as an .fbx file.
Whilst I was working on the nodes, I noticed some of the pasted groups were appearing as individual nodes, as I'd copied them, but some were showing as a single green node group.
When I copied the nodes, I just box selected and right clicked and copy.  I didn't click 'group nodes' first.

Hi :). You need to save Blender files as .blend to make sure everything works.

about 2) If you have similar materials you can create a group & add this group by Add > Group ...  or duplicate the whole material with the New Material button right next to the Fake User button. You can also add the most frequently used nodes to the Quick Favorites menu (key Q to open it. Right-click on the menu entry to add it)


text:
delete 16 vertices that are on top of each other
I looked through the blender forum and tried all the suggestions but none of it worked. My problem is I have 16 vertices that are stacked directly ontop of each other and in order to delete those vertices I have to press the delete key and then select vertices 16 times there are multiple areas where that occurs and it took me about an hour to delete all of the vertices. I want to avoid this in the future as I will be creating many of the same meshes/objects. Does anybody know how I can select and delete the vertices all at the same time instead of pressing delete 16 times?

Have a look here

You can use the Merge by Distance option.
To activate the option, use the shortcut M, than B to activate the function.
If any vertices are deleted, you should get a message like the one to the right in the screenshot.
The pie menu to the left in the screenshot are options for the function such as delete by vertices distances (from each other), selected or unselected, etc.

I googled that and tried it earlier no matter what settings I using with merge by distance it only removes 1 vertice. Sorry not the answer.

Did you try selecting or not selecting the mesh vertices?

I tried every setting

@calmchess: ok, then provide us with an example blend file, where merge distances doesn't work and we show you how it works.

I don't know how to add a file here so I put the .blend file on my webserver you can download it by putting the following link in your browser http://calmchess.com/0.zip

I've downloaded your file, hit A to select all, then M, Merge > By Distance and then Blender says: "Removed 2045 vertice(s)". What do you mean by saying you tried "every setting"?

Thankyou for taking the time to review the file. You failed to leave the puzzle piece intact and only remove the undesirable vertices around the edge.

@calmchess The puzzle piece looked very intact after doing the merge... but I guess you know better how it looked on my PC. My apologies that I tried it. ♂

Actually I reread your comment and I see what you did differently than me. Thanks for your time. I just wasn't comprehending what you did differently than me. I appreciate your efforts....forgive me I'm learning blender I'm more dangerous than good at using blender!

@calmchess As long as you don't blow everything up with a Mantaflow fire simulation, you're not too dangerous  :D


text:
select specific mesh when there are two meshes

I'd like to put the puzzle pieces together modify some vertices and then separate the two again. However when I try to select one of the puzzle pieces I can't cleanly select it because some of the faces aren't showing where the pieces connect I've tried to go inside the mesh and select the faces but I always seem to miss a bunch then when I use the move tool the unselected faces get stretched. What is the best way to connect the two puzzle pieces modify some vertices and then separate the two again?

Do you mean that you are joining them so that they are two separate mesh islands under one object, or are you using something like a boolean operation to fuse the faces of the mesh together?

If you want to grab one of the whole "pieces", select any part of it, and with your mouse over it press L

Thankyou Christopher Bennett!


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light not passing through a transparent object in eevee render engine
light not passing through a transparent object in eevee, is this just a limitation with eevee or am i missing something, I actually have a car model and i want the light to go through the windshield, but the windshield is just casting shadow. why????

Look on properties/material/settings/shadow mode.  Don't use "opaque".  Probably, use "none".

it worked, thanks


text:
The Density of Particle System is inverted between viewport and render
I am following the Donut tutorial by BlenderGuru. I have setup my particle system by weight painting the donut. The Density is set to the correct vertex group, not inverted, and the image looks great. However as soon as I try to render, and only in the render, the density of the particles inverts. It's all good in the viewport as shown in the images.
The image on the left is the rendered image and that on the right is what I see in the viewport.

How do I get them to match up. Thanks for the help.
Here is the other information in case it's useful:

Looks like you keyframed the inversion toggle (↔)

If you look at the "Density" entry, on the far right, there is an open diamond shape, and the <-> is orange.  This means that you have set a keyframe on density.

You need to clear the keyframe.  If you have a playback window, go to it and select all of the keyframes with the a key.  Then hit the x key and select "delete keyframes"

You can tell that this worked because the diamond and orange will disappear:


text:
How to make a mask anti-aliased?
I created 2 masks in Blender's mask editor. In 1 frame of my video I created the initial mask points by using Ctrl-Click. In the other frames, I dragged them to the correct position. In the node editor, I used the "Feather" option for both of them (but I don't see any difference with or without it).
Afterwards, I noticed that one mask is anti-aliased, while the other isn't:

How can I make both masks anti-aliased?

I found the answer to the question myself.
I had drawn the first mask in a counter-clockwise direction, and the second one in a clockwise direction. That caused the second one to look different (feathering at the inside instead of the outside).
The solution was to right-click the mask and choose "Switch Direction".


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How to recreate the spaghettification process around blackhole in blender?
I have been using blender from about a year and working on Blender for 3d Scientific Animations. I am very much fascinated about how NASA and ESO create because of animations of Astronomy. Can they be created using a blender?
In this thread, I am specifically asking about the latest ESO animation:
https://www.youtube.com/watch?v=AKCp-1OGGP4
In this animation, the star is ripping apart and the black hole is eating it. How can I stretch the sphere like this in the blender?

This sounds like a job for the lattice-modifier!
Outside of the funnel-shaped lattice, the sphere is undeformed...

...then it gets sucked in...

...and spaghettifies!

Make the lattice a bit more detailed and curved, and you should get what you need.
The accretion disk and jets can be made with particle systems. As for the gravity-lensing, there are quite a lot of tutorials out there that deal with making "Interstellar"-like black holes

Using a particle system and a curve guide:

Add a particle system to the sun. Tune the amount of particles and lifetime. Set the render to an object. Add an effector collection. Turn off gravity.

Add a curve in the effector collection and move its start/end to match the sun and the black hole. Set it as curve guide in the physics tab. Tune the distance so that it contains the sun volume.

Eventually, hook the curve starting point to the sun and animate this last one in position and scale, to make it vanish.

Thank you but wouldn't it put the load on particle system on the system?

@MuneebAli Hi, I don't understand what you mean?

I mean that particle systems have huge cache which can slow down the PC I guess.

You could try it this way: Create a sphere for your sun, another for your hole. Create a curve, hook its tip to an empty, parent the star to the same empty, parent the empty to the black hole. In the Properties panel > Object Data, give your curve a Bevel Depth, give it a Taper Object (the second curve) to make the tail radius shrink towards the black hole, enable the Map Taper option:

Now you can animate everything, make the sun and its tail rotate around the blackhole, keyframe the curve values, for example its Bevel Start and End:

And of course add some particles (or smoke?).

Hey, Thank you for such an easy hack. Now, my question is: "How will I continue the animation after this i.e star mesh moving on the same path and getting dump into the black hole (for the reference, check the animations in two answers above)?"

you can rotate and scale the whole thing (sun + trail), it's just a matter of could parent/child settings


text:
Particle to Blob to Surface Settlement
I want to create this type of animation in underwater scene. Here is the idea:

The polymer will be in round particles form.
On interaction with water (dissolution), the rounded particles will be converted to
cylindrical ones.
Particles coalesce to form a bloby structure while
going down in the water.
Then the blob will settle down to fill up
the canal bed to avoid seepage.

I tried metaballs, searched on web but I’m getting no idea how to animate it in a simplest way. Help would be appreciated! Thanks


text:
Import GLTF Tilt Brush via Google Poly is throwing an error
Blender Version 2.90.1 (2.90.1 2020-09-23)
I have made a very simple Tilt Brush drawing on Oculus Quest 2. I have exported it to Poly from Tilt Brush. In Poly I have published the sketch in private mode. I am then fetching a link to it via the Poly API, and download a GLTF fil (https://poly.googleapis.com/downloads/fp/1602791954433581/7xSV2Yv6hW6/6eSd6Co6PZC/sketch.gltf). When I try to import that file (standard import settings), I get the following error from Blender:
    File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 46, in from_union
    return f(x)
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 1162, in <lambda>
    accessors = from_union([lambda x: from_list(Accessor.from_dict, x), from_none], obj.get("accessors"))
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 70, in from_list
    assert isinstance(x, list)
08:11:20 | ERROR: An error occurred on line 46 in statement return f(x)
08:11:20 | ERROR: An error occurred on line 1162 in statement accessors = from_union([lambda x: from_list(Accessor.from_dict, x), from_none], obj.get("accessors"))
08:11:20 | ERROR: An error occurred on line 70 in statement assert isinstance(x, list)
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 46, in from_union
    return f(x)
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 38, in from_none
    assert x is None
08:11:20 | ERROR: An error occurred on line 46 in statement return f(x)
08:11:20 | ERROR: An error occurred on line 38 in statement assert x is None
Traceback (most recent call last):
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/__init__.py", line 928, in execute
    return self.import_gltf2(context)
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/__init__.py", line 942, in import_gltf2
    if self.unit_import(path, import_settings) == {'FINISHED'}:
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/__init__.py", line 955, in unit_import
    success, txt = self.gltf_importer.read()
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/imp/gltf2_io_gltf.py", line 164, in read
    self.data = gltf_from_dict(json.loads(content, parse_constant=glTFImporter.bad_json_value))
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 1218, in gltf_from_dict
    return Gltf.from_dict(s)
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 1162, in from_dict
    accessors = from_union([lambda x: from_list(Accessor.from_dict, x), from_none], obj.get("accessors"))
  File "/Applications/Blender.app/Contents/Resources/2.90/scripts/addons/io_scene_gltf2/io/com/gltf2_io.py", line 56, in from_union
    assert False
AssertionError

It looks like the problem is, that Poly exports GLTF v1.0, which is unsupported by Blender and others (ThreeJS, Chronos Blender GLTF Importer)

Thanks.  We're adding a more helpful error message to the glTF importer in Blender 2.91.  https://github.com/KhronosGroup/glTF-Blender-IO/pull/1238


text:
Automating Vi-Suite 0.7 beta5 version Light Simulation with radiance Workflow in blender 4.3.0 on windows 10
Hello Blender Community,
I'm working on automating the Vi-Suite light simulation with radiance workflow for a simple sphere scene  with a fine mesh which I created manually. My goal is to programmatically create and link the required nodes (LiVi Context, LiVi Geometry, LiVi Simulation, and VI CSV Export) and then execute their respective operators (liexport, ligexport, livicalc, and csvexport) to complete the simulation and export the results

Steps Taken Programmatically:

Node Creation and Linking: I've created and linked the nodes programmatically with the following Python function:

import bpy
import os
def create_vi_suite_node_structure():
    # Enable the scene in the node
    bpy.context.scene.use_nodes = True

    # Creates node tree
    ng = bpy.data.node_groups.new('simulation', 'ViN')
    print("Node tree 'simulation' created.")

    # VI Location Node
    location_node = ng.nodes.new(type="No_Loc")
    location_node.location = (0, 0)
    location_node.loc = '0'
    location_node.latitude = 48.0
    location_node.longitude = 7.84
    print("Location node created.")

    # LiVi Geometry Node
    geometry_node = ng.nodes.new(type="No_Li_Geo")
    geometry_node.location = (230, 140)
    geometry_node.cpoint = '0'  # Set to '0' for faces or '1' for vertices
    geometry_node.offset = 0.001
    geometry_node.triangulate = True  # Setting 'Triangulate' as checked
    print("Geometry node created with parameters set.")

    # LiVi Context Node
    context_node = ng.nodes.new(type="No_Li_Con")
    context_node.location = (210, -120)
    context_node.contextmenu = 'Basic'  # Set to 'Basic' or 'CBDM'
    context_node.skyprog = '1'  # Set to '0' (Gensky), '1' (Gendaylit), etc.
    context_node.spectrummenu = '1'  # Set to '0' (Visible) or '1' (Full)
    context_node.epsilon = 0.3
    context_node.delta = 0.15
    context_node.gref = 0.0
    context_node.gcol = (0.0, 1.0, 0.0)  # Green color
    context_node.shour = 12.0
    context_node.sdoy = 172
    context_node.animated = True
    context_node.startframe = 0
    context_node.endframe = 6  # Replace with appropriate frame number
    context_node.ehour = 13.00
    context_node.edoy = 172
    context_node.interval = 0.19
    context_node.hdr = False
    print("Context node created with parameters set.")

    # LiVi Simulation Node
    simulation_node = ng.nodes.new(type="No_Li_Sim")
    simulation_node.location = (410, 70)
    simulation_node.simacc = '0'  # Set accuracy level as string, e.g., '0' (Low)
    simulation_node.startframe = 1  # Start frame
    simulation_node.endframe = 1  # End frame
    print("Simulation node created with parameters set.")

    # VI CSV Export Node
    export_node = ng.nodes.new(type="No_CSV")
    export_node.location = (610, 0)
    print("Export node created.")

    # Linking the nodes
    ng.links.new(location_node.outputs[0], context_node.inputs[0])
    ng.links.new(geometry_node.outputs[0], simulation_node.inputs[0])
    ng.links.new(context_node.outputs[0], simulation_node.inputs[1])
    ng.links.new(simulation_node.outputs[0], export_node.inputs[0])
    print("Nodes linked.")

    return ng, context_node, geometry_node, simulation_node, export_node
# Save the project
bpy.ops.wm.save_as_mainfile(filepath=myfilepath, myfilename)
print("Blender project saved.")

Where the problem lies
I am attempting to programmatically export the LiVi Geometry node, as shown in the attached image below, using the bpy.ops.node.ligexport() function. The goal is to pass the geometry data from this node to the LiVi Simulation node for further processing in an automated workflow.

Overrides and Operator Execution: To export nodes and run simulations, I used the following override structure, based on community advice and simply here
summarized code :

override = {'node': context_node}
bpy.ops.node.liexport(override, 'EXEC_DEFAULT')  # Context export
override['node'] = geometry_node
bpy.ops.node.ligexport(override, 'EXEC_DEFAULT')  # Geometry export
override['node'] = simulation_node
bpy.ops.node.livicalc(override, 'EXEC_DEFAULT')  # Simulation
override['node'] = export_node
bpy.ops.node.csvexport(override, 'EXEC_DEFAULT')  # CSV Export

i refined and adjusted the code for debugging purposes
return ng, context_node, geometry_node, simulation_node, export_node

# Create and link the nodes
node_tree, context_node, geometry_node, simulation_node, export_node = create_vi_suite_node_structure()

# Save the project
bpy.ops.wm.save_as_mainfile(filepath=filepath and file name)
print("Info: Saved 'sphere automation.blend'")

# Perform Context Export
override = {'node': context_node}
print(f"Override for Context Export: {override}")
bpy.ops.node.liexport(override, 'EXEC_DEFAULT')
print("Context export completed.")

# Perform Geometry Export
override = {'node': geometry_node}
print(f"Override for Geometry Export: {override}")
bpy.ops.node.ligexport(override, 'EXEC_DEFAULT')
print("Geometry export completed.")

# Perform Simulation
override = {'node': simulation_node}
print(f"Override for Simulation: {override}")
bpy.ops.node.livicalc(override, 'EXEC_DEFAULT')
print("Simulation calculation completed.")

# Export CSV Results
override = {'node': export_node}
print(f"Override for CSV Export: {override}")
bpy.ops.node.csvexport(override, 'EXEC_DEFAULT')
print(f"Results exported to: {export_node.file}")

I also attempted using INVOKE_DEFAULT instead of EXEC_DEFAULT, but the same error persists.
Questions

Why does the error 1-2 args execution context is supported occur when using operators such as bpy.ops.node.liexport, bpy.ops.node.ligexport, bpy.ops.node.livicalc, and bpy.ops.node.csvexport in the script?

How can this issue be resolved for both EXEC_DEFAULT and INVOKE_DEFAULT contexts? also, Are there additional parameters required in the override context to make these operators work programmatically?

Where can I find scripting documentation for the Vi-Suite add-on?

If anyone has successfully automated the Vi-Suite workflow, could you share insights or examples for your approach?

Your assistance in resolving these issues would be greatly appreciated, as it will help me successfully automate this workflow and wrap up my project faster. Thank you in advance for your insights and support!

Hello and welcome. Please don't ask more than one question per post. Use the [edit] link below your post, to break this into multiple posts so that each focuses on a single issue. Make as many separate questions as necessary.


text:
First person navigation of interior model. Real-time rendering vs gaussian splatting
I've modeled a room with lots of details and it looks great in Cycles (Eevee as well with a bit of tweaking)
Thing is I want the room to be navigable similar to this: https://sketchfab.com/3d-models/futuristic-room-a60be41028b049b6a488f5c6effcb6f8 - as if it was a first person game. Problem though is that this doesn't look as good as some of the renders I was able to do in blender with Cycles.
What would be the best way to achieve this? Some research I did:

Real-time rendering: I've looked at trying to simply do this via Eevee, and it's ok (with flickering lights when moving around), but how would I export the Eevee engine for others to enjoy, say on the web? Does something like this even exist (via WebGPU)?
Gaussian Splatting: another idea that came to mind was to just take a lot of pictures of my 3d room and create a guassian splat export which could then be rendered lightly on the web:

Thoughts on the best way to do this? Thanks!


text:
what is the problem with bevel?
when I add bevel this thing appears, normal is good no double vertices

Hello and welcome. Please verbally describe what your issue is, be specific and and use relevant keywords. Avoid referencing images or links as alternative to words, try to stay away from vague references like "this happens", "issue with", "like so", which make the post impossible to find for someone using search. Instead describe what "it" is, be descriptive, succinct and detailed. It may not be immediately obvious to users trying to help what you mean. See What is the problem of asking “How do I do this?"

Maybe internal edges that shouldn't be there ?

Try a M > Merge by Distance or please share your file?

@moonboots I've already done it.

so share your file (only this object)?

@moonboots How do I do this?

read the instructions here: https://blend-exchange.com/

@moonboots , its not original file, but with the same problem

Use the Geometry > Miter Outer > Arc option of the Bevel modifier (instead of Sharp):

It will prevent the Subdivision Surface modifier to round the faces on the side:

authors: мойша турбинов


text:
Head bone moves top portion of body back, but leaves the eye lid sticking out far from eye ball
https://www.twitch.tv/videos/771914889
This video should explain everything hopefully, and it also shows a lot of whats going on with my problem.

so you don't want the eyelid to move up? in that case make sure that only the bone that is supposed to move it influence it, and not the other bones...

i would really suggest you to explain what is that is in the video so that people are not going to other platforms , and many of then might skip this because of you not giving full detail , so elaborate what you want as a text , small videos are Okay but this is too big

@moonboots but then it wouldn't move in unison with the mesh around it.  Also, having no other weights assigned to it from other bones would make it move without stretching, so blinking would no longer work.

if it's parented to a bone which is parented to the head bone, it will move along. For the stretching you can create a second bone to control the eyelid or a lattice?

@SHikhaMittal The video explains almost everything within the first 2-3 minutes, the rest was me going through the bone details again.
I'll summarize my problem:
I have a mushroom character with an Eye below the Mushrooms cap, this is the Eye I'm trying to rig up for eye tracking, but the Mushrooms cap is his head.  So when he leans backward the Eye below the cap tries to follow him, along with the Eye lid, and during a Blinking Animation it appears that the bottom of the Eye lid will be jetted out too far from the eye ball, meaning there is a gap between the eye lid and eye ball.

@moonboots I need something to be applied to the bottom of the eyelid when the character leans back to bring the bottom of the eyelid closer to the eye.

If I open the N panel in Edit mode, I can see that the eyelid is influenced by Head, Chest and Highhigheyebrow, while it should only be influenced by the latter, and maybe some other ones if necessary

@moonboots  that just won't work though, because when I rotate the headbone to look up or down in the game I want to export this model to, the eye brow needs to move with the skin around it, like... I can't have it moving out of place, so it needs to be weighted to the chest and head like all the skin around it is.

maybe try shapekeys, and shapekeys with drivers?

"why not just use the bone to make a shape key for blinking then remove the bone after transfering it weight to the head"
this ended up working for me!
I made a shape key with the uppereyebrow bone (Highhigheyebrow) using the CAT5 (CATS?) plugin, then I renamed the Vertex Group for Highhigheyebrow to Head2, which applies it to the Head2 Bone, and this works!


text:
Visualize rendering time per pixel of scene?
Is there a way to visualize how long each pixel took in terms of GPU computation time of the render?
e.g.something like a heatmap of computation.
I know it exists for other render engines but I can't find any info on something similar in Blender (and even doesn't know if it is relevant for the Cycles engine).
This would be helpful for identifying problematic shaders or optimizing the scene render time.

Yes, there is: the Render Time pass, available under Scene > View Layer Properties > Passes > Data > Debug. See official documentation.
You can view each of the render passes individually through the compositor, or by saving the render as an "OpenEXR Multilayer" file.
EDIT: This feature was removed in version 3.0 without an update to the documentation.

It seems perfect regarding the topic but unfortunately, I haven't been able to find it in the last version (3.5.1). Whatever I do and try, the Debug passes only contains "Sample Count" and no "Render Time". How do you enable it?

I confirm that I also tested 3.6 release candidate and that it does not show the Render time pass either.

Sorry but the proposed answer is not accurate. From Blender 3.0+, this option has been removed as it only worked with CPU and the former model.
I just sent a ticket regarding the fact that it's not available anymore and it has been confirmed as an error in the documentation :
https://projects.blender.org/blender/blender/issues/109364
As long as there is no new option, I'll keep the question open :)
EDIT : updated the answer according to ticket updates


text:
Texture coordinate UV - black?
I face a weird behavior which I cannot understand, therefore any help would be appreciated.
For one of my objects, the "texture coordinates/UV" value is all black which seems to indicate that it doesn't work.
For the other ones everything is fine.
I've tried to unwrap again, either classic unwrap or smart or cube, without success. I've also tried to recompute normals or flip them but it doesn't change anything.
What can possibly go wrong here?

https://blend-exchange.com/

Is it intentional that there are several UVs overlapping each other? It would also be interesting to see the complete shader nodes setup and not just the Texture Coordinate node...

Thanks for the comment. The overlap is the result of the default cube projection unwrap.
And actually, the shader node is just the texture coordinate node sent to the output, that's why I only showed it.

I found a temporary solution though not understanding why it worked. I copied the mesh from the "black/non functional" object into one of the "colored/ok" objects which seemed to recreate the UV coordinates. Then I split the mesh by "selection" and the new object kept the UV coordinates.
I still don't understand what was the issue and why that operation fixed it.


text:
Save/customize the file browser interface
Everytime I open the file browser interface, the directory windows on the left are arranged as default. Even if I switch Recent on top of System and minimize System, the next time I open the interface, it's gone and back to default and I have to scroll down all the way to select the ones I need.
Is there any way to save the interface disposition? Or to force its look with some script?

Maybe you could store your projects in individual files saved to your desktop?

I'd still have the System and Volumes windows to browse, so I don't see how it would help.


text:
How to smoothen normals in geo nodes without smoothing the geometry?
I'm trying to get a simpler shape so that certain effects (e.g reflections, transmissions, caustics) are easier to compute with low samples.
My idea has been to smooth the geometry with geo nodes and get the modified normals to test how it works when rendered. And it looks promising but I'm stuck.
I can't get the normal attribute of an unconnected branch in geo nodes to be exported.
And I don't want to apply the shape modification either.
Any help on how to smoothen normals either in geo nodes or in the shader appreciated.

Actually, the value has to be transferred back to each vertex of the original geometry using a Sample index.
Learn something every day :)


text:
Correct Sculpting Workflow for Animating Mouth and Eyelids / Human (and Animals)
I've recently tried to sculpt a Human Mesh. I was wondering, however, to approach the mouth/eyelids part of the head.
I want to animate this mesh and I will obviously Retopo the whole thing. The character will talk - open his mouth to show teeth and tongue and the eyelids will close/open. The camera will be very close to the character so I can't just fake it.
The model I've created has an eye socket and a mouth socket scultped inside but if I try to remesh it It requires me to go to absurdly low level of voxel size otherwise the space between the lips for example will be meshed together.
I cannot afford to go this low in voxel size since I'm doing a full body so what should my approach be?
Should I Just get the external part and then, once I've retopologied I need to box model the inside socket?
What is the best plan of action? Thank You :D
ps: I've attached a reference image of my mesh. It's not important but this is my current sculpted situation.

I suggest you search youtube for "blender character animation shape keys"

I'm guessing that by "voxels" you mean vertices? And are you talking about the side-effects of the simplification of your mesh once you reduce the vertices/polygons?

Thank you! I will look onto it
Yes! The Voxel size affect the number of vertices in my model (as I've understood, at least x) . Regarding the side-effects I can give you an example. I have a low poly head with an internal mouth socket (where I would put teeth and tongue). I've sculpted a pair of lips where the upper lip is close to the lower lip. Remeshing by going for a low number of vertices will cause a merge between the vertices of the upper and lower lips. I can resolve this by going extremely high poly. What is the correct workflow for creating a functioning mouth in a human body?


text:
my donut is always a mess
I tried creating donuts many times but the same problem occurred every time. I don't know why it is happening. Please enlighten me with some knowledge. Please save me from this mess.
I am following blender guru's new beginner series.

You have the Snap and the Proportional Editing option activated, the second one moves all the vertices that are close to the one selected, depending on the size of the influence sphere, and the first makes the selection stick to the face you'll meet, you probably ended up with this messy result with some unwanted movements of vertices. Make sure you know how these options work and disable them as long as you don't need them:

To clean up, you can select the inner edge loops with AltShiftLMB, delete them, then recreate a clean topology:

Those are both used together in that part of the tutorial to produce the icing drips as far as I can remember.

sure but I guess he must be careful about how he moves his vertices when these options are enabled, don't you think so?

proportional editing and snap-to-face are enabled to keep the icing stick to the donut and I don't understand this topology thing and kbd. I just selected outer vertices but I don't know why this happens. I am completely new to blender.

Sorry, I've edited my answer, I hope it's understandable now   ;)

@YashGoyal I suspect you had the influence set far too high when you initially enabled Proportional Editing and distorted far more of the icing mesh than you intended. You can change the circle size that appears by scrolling the mouse wheel and it can be scrolled so large that it disappears from the viewport altogether. That will distort a very large area of the mesh without moving the mouse far when you grab a vertex.  Delete the icing, separate another section from the donut and try again starting here.

@JohnEason but I reduced the influence of proportional editing

I saw that from your Blend file but it looked as if the damage had already been done! I can't see anything else that could have caused it.


text:
How to make my fish warmer and cozier
I'm fairly new to blender, actually I modeled my fish in Fusion 360 then imported the mesh to blender and assigned a colored material to them. I'm looking for a warm cozy, cartoony (but not cell shaded look).
I'm not sure if I should be looking at lighting, shaders or what :)
Here's how they look now in blender.
And a little better in godot with the lighting turned on.

Thanks for any advice!

For the moment your fish is a bit flat, maybe you should give it a more rounded shape. Also you should rework the material, give it an Emission color so that it has less shadow, and perhpas a bit of Subsurface to make it a bit translucent:

Awesome, thank you!


text:
Why does my mesh kink when I bend my bones
I'm new to blender and trying to make a corner joint that I can set the angle of in Unity. Ideally if I set an angle like 45 or 90 degrees the bend would look uniform like this:

So I set up a rectangle in blender and gave it some bones. And I can move them in pose mode and even in Unity when I import it.

If I bend it too far though, the mesh kinks like this. The inside bend looks more like I tried to crush a can than a smooth bend. I tried adding new bones but had the same problem.

And for some reason the end bones don't deform the mesh when I move them. Almost like they aren't attached or something.

This is how it's setup:

So how do I make my mesh deform nice and smoothly like I'm bending a pipe?

So how do I make my mesh deform nice and smoothly like I'm bending a pipe?

By spreading your rotation out over more bones:

A bone can only ever represent a single rotation, not a continuous set of rotations, and vertices interpolate linearly from the orientation given by one bone to the next.  To make smoother deformations, sometimes we just need to use more deform bones.  (We also sometimes just need more vertices.  I wouldn't add more bones than the most shown here without adding additional vertices to my mesh.)
I don't know if Unity supports "quaternion skinning", but if it does, you can try enabling volume preservation, which will improve this kind of deformation at shallow angles, although at the risk of making it worse at sharper angles:

it doesn't look as nice as in his picture. the inner part of the bend is not a vertical line. probably bones will not make the cut?

is there a difference between segmenting a bone or creating several bones, like you did? Are segmented bones compatible with Unity?

@moonboots bendy bone segments are not going to be compatible with anything but Blender.  There can be differences between more bones vs bendy bones, depending on the values you pick for the bendy bones and the angles you pick for rotations of multiple bones; bendy bones look like spline controls and handles to me, where it's just a simplified interface to spline IK.

ok thanks for the precisions  ;)


text:
The lights object data properties has vanished
Using Blender 3.6.3 initially, just installed 3.6.4
At some point I realised that all Object data properties have gone meaning im unable to make further changes to the lights in the scene.
Tried many things including updating to 3.6.4, which resolved problems in the past.
Clearly I'm new to Blender but I don't think I touched anything I shouldn't.

Even for a new blend file? Switching to Workbench Renderer the light properties are quite limited, but even there you should be able to switch between light types ...

Ah Good point. In both workbench and Eevee light type returns but not in Cycles. Thanks though

So ... it can be a bug  ... so check it if reported on Bug Tracker ... or isn't it cross version issue? Have you tried a new file wit File > Defaults > Factory Setting?

Brilliant. just reset to factory and reopened file and there they are. Many many thanks vklidu. Oh, how/where would i find Bug Tracker.

Great it worked for you. If that helped it could be some addon conflict ... to report a bug on top row go to Help > Report a Bug :) Just if Factory Settings worked for don't post it as a bug since the problem lays at some third party code. You should test what is causing this issue specifically (what makes th e properties hidden) and than try to contact someone specific.

Thnks. It hasn't happened since and so leave things as they are to see if it happens again and then turn off add ons to see if i can locate the problem.


text:
Import other fbx files, and the pivot always outside the objects with a parent relationship line
I imported a ready-made grass .fbx file that was made by others, but the pivot was always shown outside the object with a black dashed line, which seems like the parent relationship line.
My purpose was to make the position change of this grass object, but every time I opened the project again, the grass remained in the same location that hadn't changed.

Alt-P with the object selected in Object mode will unparent it, but it's not clear what it's currently parented to. It's possible that it's parented to an Empty with the empty hidden.

Thank you very much for refreshing, unfortunately, I have tried to unhide everything to see whether something was parented incorrectly,.Whilst there was not, the grass. fbx itself was an assembled file originally, so I was not able to unparent it by selecting the grass file. I'm also wondering how to share my project file in this platform as this is my first time using this platform……

As long as your Blend file is under 30Meg in size you can share it via https://blend-exchange.com/ following the instructions there to copy the link on that page and then edit your question here and paste the link into it.

https://www.dropbox.com/scl/fi/ofmt1ter1ff9t45dop2sa/problem-file.zip?rlkey=h9zcgzgjflgpvpqruv5ipnxcz&dl=0
I don't know whether this link can be shown, which is the link I upload my files onto DropBox cloud disk as the size of the blend file exceeded 30MB

It downloads and opens fine in Blender but I'm afraid something that complex is outside my experience. Maybe someone else here can help?

You're so responsive! , maybe I imported the camera things as well, I will figure out it little by little,really appreciate it


text:
Mesh is not editable in edit mode, but shows properly in object mode

I downloaded this project file, I want to edit this book mesh in Edit Mode.
However, when I go into Edit Mode it just show the blank mesh with no possibility of editing, while I can see the edges, vertices and loopcuts in object mode.
How so? Is it some vertex group magic? I am not well versed.

Your object has been made with geonodes, you need to convert to mesh (applying the modifier doesn't seem to entirely convert to mesh so I guess you need to create a node within the geonode setup)

Thank you! Thanx for the reply

To be precise: the upper connection going into the Join Geometry node needs a Realize Instances node plugged in-between. Or you can put it simply between the Join Geometry and the Group Output.

Hi. Please don't post essential information like links, file downloads or additional details in the comments section where it can be easily missed. Instead edit them into your original post with the [Edit] button above. Comments are transitory by nature, are hard to index or search for, and may be erased at any moment.

The book is generated using geometry nodes. There is no editable geometry. Switch to the "Geonodes" workspace to see the node tree.
Perhaps this belongs in a comment ? I'm not sure. I see Moonboots responded in a comment already
If you want to convert this geonodes book to editable geometry, you need to apply the modifier (ctrl+A in the modifier list). However the object contains instances, and those will be absent in the resulting mesh if you apply it right away. So you need to first enter the nodetree and add a Realize instances node at the end (which converts any instance to a proper mesh), only then can you apply it.
In the capture below I am showing the very end of the nodetree with a Realize instances node added right before the output. At the top, I've opened a spreadsheet editor to show exactly what the generated object is made of. As you can see, there are 14 instances (they still appear in the list because I temporarily muted the Realize instances node).

Thank you! Appreciate it

That's it but maybe explain how to convert to mesh? I think there's a node but I don't know enough about geonodes to answer

Ah yes, good idea


text:
Why does the Cycles render engine add this cube?
I am very new to using Blender. I was wondering why the Cycles render engine add this cube to my rendered picture when it doesn't do this with the EEVEE engine. Thanks in advance!

Hello could you please share your file?

okay i restarted the application and now its gone. i guess i should have tried that first hahaha.

OK that was weir....   ;)


text:
Textool 1.5 crash in install in Blender 4.0.1

I have downloaded and install Blender 4.0.1 on my new computer. When I try to install (or really activate) TexTools it failed with following dump.
Does anyone know what's ongoing here? Seems to be a problem with import "Facemap".
In my last 3 version (3.6.0) all works fine.

Probably the same as https://blender.stackexchange.com/questions/304948/blender-4-0-crashes-when-opening-home-builder-products-build-decorations-materia

The original Textools by renderhjs was last updated for Blender 2.79.
SavMartin forked it to update it to Blender 2.80 and has been maintaining it since with the help of other people from the community.
Any time a new Blender version is released with breaking changes in its Python API(which is the case for 4.0), addons are likely to need an update to be able to work in that version.
SavMartin's TexTools received updates in the past days since 4.0's release, so you maybe you can already download the updated repository and install it, it might already work as is. Or wait for them to post a new official release. If the current repository doesn't solve your bug, you can report it in the Issues page.

can confirm the latest update fixes this issue.

The Master branch was suggested on github and it worked for me on 4.0.1
https://github.com/SavMartin/TexTools-Blender/archive/refs/heads/master.zip
berfore that I was using 1.5 release which broke on Blender 4.0


text:
Animate sphere pulled by chain
I wanted to animate a ghost that pulls a chain with a metal ball behind itself (like the typical comic prisoner).
The problem is that I couldn't find a way to even get remotely close to what I want. I want the chain to be attached to a point that I can move around with keyframes on one end and to the ball on the other end. The ball collides with the ground and ideally also poses some resistance to getting dragged along.
Is there a way to achieve this?

maybe you should google or search here...so you will find a lot of answers like this so you will get a starting point https://blender.stackexchange.com/questions/7280/reel-in-anchor-using-physics/7286#7286

https://blender.stackexchange.com/questions/226766/how-do-i-pin-a-ball-to-a-cloth-sim-rope-to-create-wrecking-ball/


text:
Dark spot after texture bake
I'm using SimpleBake to bake a room to a texture, but I get a dark spot on the couch.
Params:

Engine: Cycles
Samples: 8192
Bake type: combined
Colour space: filmic log
Denoise (Cycles)
Bake / Output at 8192x8192
New UV maps

Thank you

... maybe you baked with some object that is hidden now? ... if you attach couch into a new blend and bake it again does it happen too? Also there is more wrong things in the scene https://imgur.com/VkKcx3G ... btw couch shading (seen on right-blue screen) doesn't seems to look good ...

@vklidu thank you for your input. I will check


text:
How should I create a stylized, semi-waxy skin in Blender (Eevee)?
I am attempting to recreate the skin material created by Dmytro Bajda within zbrush, but in blender instead. I am specifically attempting to create procedural skin that looks like this:

^This is from their post "More sketches and WIPs".
For reference, within zbrush, this material is based upon the default "skin4" matcap. It has a unique specularity curve and about half of the wax modifier within in.
This also has been polypainted (in areas like the lips, eyes)
I have tried numerous times, with the principle BDSF and without, but cannot seem to get the finish/color correct.
More color-accurate attempt:

And a more texture-accurate attempt:

At this point, I feel I am needlessly complicating the material; thus, I am curious if anyone might be able to give some insights into how to create a material like this one.
Thank you for reading all of this! I hope you have a wonderful day-!

One question first - what is your lighting setup?

@AllenSimpson I have three point lights each with a radius of 1.5. They two side ones have a brightness of 100, and the center one has a brightness of 180. Photos Here: https://imgur.com/a/JozvREn


text:
Thumbs rotated wrong for Auto-Rig Pro - after retarget to Mixamo animation. How to fix?
Please help, Ty. I searched “Auto-Rig Pro” thumb = no results. Also searched Youtube.
Problem: I rigged my character using Auto-Rig Pro. (Idk if it's IK hands, no one taught me.)
Q1: When I retarget my rig to a Mixamo animation – my thumbs are rotated wrong. What is the issue? I don't want to manually reanimate my thumbs because I have 20 Mixamo animations to do.

Stats:
Blender 3
Auto-Rig Pro 3.65.39
Year 2022: people should have this addon by now (searched old answers saying people dont have this).

Steps:

Blender 3 > Rigged my character mesh using Auto-Rig Pro, in T pose (“Rig 2”). Thumbs seem to have 3 thumb bones (rings). Mixamo anim has 4 thumb bones (but one is a tip bone at end of finger/thumb, unused?).

--

I downloaded an Idle animation from Mixamo, using their girl bot character. Saved with and without skin to test both (see their thumbs).

Imported skinless Mixamo animation (“Rig 1”) into Blender using Better FBX Importer. I tried the checkmarks for “Optimize For Blender” = on/off, doesnt seem to make a difference.

Automatic Bone Orientation is On. Fix Bone Poses is off. Idk if this matters because after Importing the Mixamo animation – their thumbs look correct. It's my rig retarget that fails later.

Blender > ARP plugin tab: Select Rig 1 > Redefine Rest pose. T pose activates, Check Preserve > Apply. (After Apply, Rig 1 resets to its default animation pose – which I think is normal.)

ARP plugin tab: Select Mixamo as Rig 1. Select my rig as Rig 2 > Build Bone List.

Source Bones = 3 Mixamo Thumbs (Rig 1) auto match to my 3 thumb bones (Rig 2)

Select Root bone > Set as Root.

Did not click Auto Scale (doesnt seem to fix anything, or makes Rig 1 skel too small).

ARP > “Re-target” (apply Rig 1 anim to Rig 2). (Rig 2 is in T pose.)

Animation gets applied = Rig 2 goes to Pose animation. But Thumbs are rotated wrong. What is the issue?

--

Tried importing another Mixamo animation (Slow Run) > Apply = thumbs still rotated wrong on Rig 2.

Do not want to use Mixamo's rigger because the point of me using Blender to rig, is Mixamos rig window is too small = imprecise joint pins.  But IF I import this Character to Mixamo and rig > thumbs do rotate correctly (but animation problems with the thigh/crotch = mesh warp that only ARP is fixing).

For step 11, what is the correct way to Rotate the Thumb and apply that rotation to all Keyframes? [I found a vid how to do this, but lost the name. And not sure if I'm doing it correctly (how to set Linear/curve animations?): If the animation is making the thumb move from A to B – instead of staying in the same relative location to the palm... then how do I correctly rotate all the keyframes of the A-B Thumb animation – but merely change its starting Rotation (so it still cycles from A to B – but now at a different starting Rot)?]

Questions repeat:
Q1: at # 11: When I retarget my rig to a Mixamo animation – my thumbs are rotated wrong. What is the issue?
Q2: at #14 above.
Q3: I see people import Mixamo animations (Rig 1), which import at 0,0,0 axis. Then they move Rig 1 on X axis – so it doesnt block the view of their character (Rig 2). How do I do this??
I tried G X – move. But when I click play, the Rig auto jumps back to 0,0,0 – blocking my view. I tried to Apply Transform after moving Rig 2 – but it ruins the arms (location offset) of the retargetting animation on Rig 2.

Q1: In ARP there's a tool called "Interactive Tweaks" which is useful to correct this kind of problems, but it works only on Euler rotations, so you'll have to set thumbs to euler rot in order to use it.
ARP Documentation
Q2: In the Graph Editor you can select all control points of a channel (i.e. X rot of thumb_01 bone: select the channel and press Shift H to isolate it) and press G Y to move all curve introducing an offset which will preserve the relative rotation modifiyng its start (and end) position. Again its easier to edit curves in Euler rot mode, but you can try the adjustment even with quaternions (better if you understand how quaternion math works).
Another method is to add an addittive layer of animation, using NLA, so that you add an offset rot to the bones where needed.
Q3: After importing  a Mixamo FBX you can select its armature in object mode and move, rotate and scale it (always in object mode) as you like: the animation will be preserved. Don't apply anything and be sure that you don't have animation record button enabled, so not to set any keyframe on the rig while in object mode.


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Combining two profiles to a volume using geometry nodes
I'm interested in trying to create a surf fin. Is it possible to combine two profile curves to create a volume in Blender such as can be done in Rhino + Grasshopper? I am able to create the profile using curves, but am not sure how the two can be "blended".

The reference paper: http://www.cad-journal.net/files/vol_18/CAD_18(2)_2021_297-308.pdf

Seeing as this is based on a specific article about some specific other software, I think you may need the expertise of someone proficient in both Rhino's Grasshopper and Blender's Geometry Nodes to sort of "port" the technique over. Is the ultimate goal to 3D print a variety of different fins by tweaking the parameters of the node setup? Or do you just need one fin? If just one fin, I might suggest keeping it simple and going the polygon mesh with subsurf route. Bear in mind Blender is primarily a 3D animation suite, and you're comparing it to CAD software for product design here.