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What's wrong with the prefetching?
I'm currently messing around with camera tracking and I've noticed a strange issue. Whenever I prefetch the footage, it works, but from frame 129-160, the blue line isn't there. On playback, once the footage reaches frame 129, it pauses briefly, prefetches those frames as it plays, and from frame 0-47, the blue line disappears instead. And then everything resets and repeats when it reloops the footage.
I'm not sure what's happened, but is there any way to fix this? I've attached my save.

Blender probably doesn't have access to enough memory to prefetch the entire clip. In the system tab of the user preferences try increasing the cache limit (I think that's what it's called, don't have blender in front of me right now) to something a bit higher. Ultimately it's limited by the RAM on your machine, but doubling it should be fine.

Odd. I thought I'd changed that to 8Gb... Either way, that's fixed the issue. Thank you. :D

@Brenticus this works like a charm- for me i just set the cache limit in user preffrences/system to 5300 afterwards it prefetches beautifully.

You probably need to set a higher cache limit in your preferences. It is under the System tab. The default is 4 GB which may not be enough for what you're doing.


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Can't add a Follow Path Constraint in Object Mode
For some reason I can't work out how to apply a Follow Path Constraint to my character in Object Mode. Something has gone a bit wrong in my outliner somewhere... The option to add a Bone Constraint appears in Pose Mode no problem, but selecting the rig in the hierarchy won't allow me to add a constraint. All the options are greyed out. I've tried selecting all my objects and grouping them, but that doesn't work either. I'm a bit stumped as to what to do.

Thanks

in Pose mode you will have the Bone Constraint available, and in Object mode you will have the Object Constraints available, and it works fine with your file

Odd. Can't get it to show for me. How have you done it? If I have my model's layer active, the armature layer, select the armature, I can select Pose Mode and have access to the Constraint property. If I select a part of the model and I'm in Object Mode, I don't have it. :-\

I'm such a fool. The option was there the whole time. >_< I got confused due to the button looking different from the Constraints option for bones. Though I am having problems getting my character to walk along a path.

source: Stack Exchange

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

sort: votes


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Material Instances Using Same Node Set Up
I’ve set up my material using all these nodes, which also has an image texture Node,
I’d like this material to be applied on other objects as well. but to be able to change
the image texture on the object(s).
So rather than clicking on the Plus icon, which will add new material and I have to redo the nodes up again.I click on the Icon NEW MATERIAL (indicated in Teal colour), so I can duplicate the existing material Node set up and assign it on another object(s).
So I add a sphere to my scene. Now when I try to change the image texture on the sphere, It also affects the rectangle as well. So what ever I add in the image texture node
its affecting both objects. So how can I have the materiel node set up, but to be able t control each objects image texture separately?
I had the impression that by making a duplicate of the materials it becomes an entity of its own, so you can affect the object you choose without altering the appearance of the other one since it’s a new instance, and has a different name, e.i: Material Start, Material Star.001, they’re both named different to target each object differently.
Thank you.

It's true that making duplicate material, the new material is a new entity. But what you may miss is since you have multiple materials in an object, the object may still use the same material as the sphere. Try this:

Select the object with multiple materials.
Enter edit mode, select faces that you want (or I assume you want to select everything)
The materials section now will have Assign, Select, and Deselect.
While the faces are selected, select the material you want from the materials list, then press Assign button.

I click on the Icon NEW MATERIAL (indicated in Teal colour), so I can
  duplicate the existing material Node set up and assign it on another
  object(s).

You don't have to do this to be able to assign it for another object. You can just select other object, then click the material icon next to the name field, then choose the previous material with the node set up.
Note that Blender doesn't save unused material (indicated by 0 in front of the material name when you click materials list), means the next time you open the file, they won't be there, so instead you can just make sure the material is used by an object to not disappear later when you open your file.
OR you can also preserve unused material by clicking the shield icon (fake user button) next to the duplicate button, so it is saved even though no object is actually using it.

Hi and thank you for replying to my question. Point taken regarding how to assign the same material on every new object, but there is a problem I cannot solve, since every object is sharing the same material, and have the image texture, when I change the image, it changes in all my objects, and when I delete the image, it deletes on all my object where the same material has been applied.

That's the point of sharing same material, so you can edit once and applied everywhere, if you don't want that, then you need to duplicate it, not sharing it.
Notice that there is number shown if the material is used somewhere else. In your screenshot, there are 2 objects sharing the same material, so just duplicate it to make them independent.

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


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Simple deform modifier to sphere shape
I read upon a previous post regarding the simple deform modifier.  But in this case I have made from honeycomb shapes a mesh, and have used 2 Simple deforms modifiers.
And I'd like to get it looking like a sphere. But the top and bottom doesnt look spherical, rather than squashed towards the poles. (South, north). I tried using the cast modifier, but made the sphere look awful. Any other way I can get this mesh looking round like a sphere?
Thank you.

You can't actually tessellate a sphere purely with hexagons, the geometry doesn't work out.
However, a few (12) intrusions of pentagons make it possible. That makes a sort of expanded Buckyball, or soccer ball. If that's acceptable, the only route I can find to it at the moment is to enable the shipped 'Tissue' add-on, create an Icosphere with enough subdivisions, and ask Tissue to 'Convert to Dual Mesh' it.

I could have sworn you could get to this directly, at one time, using the 'Add Mesh: Extra Objects' add-on, but I can't find it in 2.81.. maybe someone knows?

Thanks for this tip Robert.
I got the result I was after within a minute add on + wire frame modifier. But I feel like I cheated the software and myself. I was mainly trying to achieve this result via a harder skill/technique so I can understand how an individual would do it manually, without the help of an add on. But because time is valuable to all of us, the result and new add on is more than welcomed.
Thank you.
https://ibb.co/23c0qL3

@blenderbreath Totally agree. I always feel you need to know stuff bottom up, otherwise, when the time comes, you don't know how to invent new ways for yourself. In this case, though, there's mathematically no way of deforming a hex grid into a perfect sphere.


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How to Create Procedural stars using nodes for EEVEE
Is there a way to create procedural stars using nodes? I learnt a few days ago, how to make stars for the background using nodes set up, but what I'd like to know is if it's possible to make scattered stars from a mesh.

You can create the stars with icosphere and this kind of material (mix between Emission and Transparent nodes with a Layer Weight as factor, remember to choose Alpha Blend in the Material Settings > Blend Mode):

Then create a cube, give it a Particle System / Hair, Emit From > Volume, with the icosphere as render object, give it scale randomness, disable the Show Emitter option, or give your cube a transparent shader.

At last, give it a glare effect in the Compositor:

Worked well, but how did you get your cube opaque? I can still see my one. https://ibb.co/KwfX8WW

you can either disable Show Emitter in the Particle panel, or choose a transparent material (don't forget to choose Alpha Blend in the Material Settings, like for the stars)

Unchecking the shower Emitter didn't fully work, until I googled this here as well: https://blender.stackexchange.com/questions/129173/how-to-hide-the-object-emitting-particles-in-a-render-in-blender-2-80

mmh ok, it works for me though, I don't know what's happening

Not for the first time, curious about why you prefer to use hair, than an ordinary particle system. My ignorance... clumping? physics?

if think both work but Hair is probably easier to set for this kind of purpose?

typically for this kind of purpose where you don't need to move the particles it seems more logical to use hair, no?

In regards to moonboots answer - to make the cube transparent, make sure you uncheck show emitter in both render and view port tabs


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How to reveal unmask a series of object using animation keyframes or nodes
I have a set of traffic lights, Which I'm using a Boolean method to unmask/Reveal as I move my Boolean mask up and down the Z axis. I have also keyframed my Boolean so each traffic light gets unrevealed as I move one frame forward.
Is there another quicker or more intuitive method for this? The reason I'm asking is, I have 3 colour lights I'm revealing, but if I need to do 20 or 30 lights, it's a tedious task to keyframe the Boolean mask. So can it be done using Geo Nodes, or some other technique someone can share with me?

File included:

with this node tree:

you will get this:

This method is a lot faster than yours because it doesn't use boolean operations which are very slow in Blender.

Hi Chris, is it possible this method can be used in Vertical direction, for example, if I have 20 spheres Bottom-Top to be revealed one by one? This image is only for a demo. (Can be any shape) Imagine if each light opens up as its revealed.
https://i5.walmartimages.com/seo/Monster-LED-Sound-Reactive-Rechargeable-Multi-Color-Color-Flow-LED-Equalizer-Light-Bar-Livingroom_26703779-ab77-492a-947c-a1e3fa1979b8.fae2ca83c0b7c3a4850213437e03fe52.jpeg

if you have just one object with 20 mesh islands it should work

Thank you Chris!

you are welcome


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How to mirror gradient material
I have an object and applied mirror modifier with a gradient texture. The problem I'm facing is, the other mirrored object on the left, doesn't have the same texture coordinates like the original object on the right. Even on the right object I hade to change the settings of the mapping node, scale and location, so the gradient appears on my object.
The only way I figured out to fix it, was to apply the mirror modifier, and then apply the material to the left object, and then play around with the mapping node to make the gradient appear where its suppose to be located.
So what's the correct method to get the mirrored object to appear like the original object with all the materials, and to be in the exact location on the object.

If you're using the Object's own coordinates in the shader, you would just separate the X component and absolute value it. But it looks like you're using the coordinates for a differet Object, which makes it more complicated.

Is the object used in texture coordinate node intended? Or is it here because you're searching for a solution?

@lemon, I saw this node set up on YT, how to control gradients, so I have Object plugged into Vector, and move the location so the gradient can slide left-right, until I can see it on my object.

If you're using a mirror modifier you can check Mirror U or V and use the UV coordinates

In this case, you can make sure that the shader depends only on the absolute value of the X coordinate, since this is symmetric across the YZ plane.

So many great explanations, thanks so much guys. Always learning from this forum.

I guess you have to associate a coordinate-system with the mesh before the Mirror modifier gets to it. One way, as Gorgious suggests, would be to use UV mapping, and the facility provided by Mirror.
Another way might be to store the Position attribute on the mesh, above the Mirror, and then use that, in the shader:

Here, called 'Base P' in a 'Store P' GN modifier above the Mirror, and used like so:

For this result:


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How do I fix the placement of these bones?
I'm really confused with the placement of some of the bones in my rig. The controller bones for the fingers (the ones in green) keep moving whenever I jump into Pose Mode from Edit Mode. The same happens to the C_look_target too; it appears behind the model. How can I fix this so they appear in the same place in both modes?

Thanks

It's because your D_Hand_L bone has a Copy Rotation constraint with a Space > World Space <-> World Space while it should be Local Space <-> Local Space. It was dependent of the rotation of the other bone in the Global Space so it was rotating a bit as soon as you entered in Pose mode.

Okay, that's helped somewhat. Though now I'm having issues with my controller bones for the fingers. In the reference model I'm trying to replicate, the deform bones (in red) shouldn't be moving, only the green controller bone. None of the transforms are locked for the reference model either. However, with my deform bones, they move parts of the finger, but the control bone doesn't do anything, and I'm not sure why.

So it's another question


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Keyframes deleted but model still 'floats'
I'm trying to redo my walking animation. I've deleted all the keyframes under the Dope Sheet/NLA Editor etc., but my model still 'floats' along when I hit play. Prior to removing everything I could find, there were no keyframes showing on the Timeline either. Even if I selected the Armature, the keyframes weren't showing. How do I get them to show? How can I stop it floating along?
Thanks

In the Dope sheet have you clicked the Ghost and the Life ring icons to show additional keyframe data? If the does not help I think you would need to uplaod the .blend for us to look at https://blend-exchange.giantcowfilms.com/

I hadn't, no. Looks like there were a couple of keyframes for the start and end. It's sorted now. Thank you. :D


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How can you keyframe textures changing?
I'm trying to figure out how I can keyframe a texture change. With three of my animations, it uses a default texture of the character smiling. For the Attack animation, my texture is the character showing his teeth in an angry way. Older guides I've come across suggest keyframing the textures. This doesn't appear to be an option anymore? Another one showed a Node setup where there was a Mix/Mix Factor, which again, is no longer available. It's just Mix Shader. If I can't keyframe textures changing, what setup could I use with the Nodes? Or is there an even simpler method available?
Thanks

Setup a material with two Shaders and Mix Shader then hover over the Factor value in the Mix Shader and hit "i" this will create a key frame. Just set your keyframe to 0.0. or 1.0 depending on which Material you want to appear at that time. Can be extended with a "tree" of Shaders and Mix Shaders.

There are multiple options:

you can animate the nodes in the material itself to mix multiple textures (animate factor of Color > Mix node):

put all your textures into a single image (image atlas). Then you can use the UV Warp modifier to translate the UV coordinates across the image atlas.
To control the modifier:

create an armature rig and animate the bone positions (as shown in this UV Warp tutorial)
create an integer custom property and use it to drive the bone/empty location in single axis. The image atlas should be an image strip with equally spaced images in this case. Then you keyframe the integer property that switches all the textures.

Awesome. I've got that setup correctly at least. However, whenever I press 'i' on the Roughness, no keyframe is being added in the Dopesheet or the Timeline.

@DustyShinigami You need to have that node selected so it shows in the Dopesheet I think.

That certainly adds a keyframe to the Timeline, but it isn't showing up in the Dopesheet, I'm afraid. Also, the whole method isn't working or ideal for what I'm trying to do. I can't set the texture to one thing for an animation strip and then set it to another for a different strip. :-\


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Weights aren't mirroring
I seem to be having an issue with mirroring weights (again). I have X Mirror enabled, painted one side, gone to Data > Vertex Groups > and selected Copy Vertex Group and even Mirror Vertex Group, and even if I rename the copy so it's something.L and something.R, it keeps putting the mirrored version over the top of the one that's already there. What am I doing wrong? How can I fix this?

Once the upload feature works correctly, I'll upload my save. It just keeps telling me 'error uploading'.

Nope. Can't upload my save, unfortunately. I just keep getting 'error uploading'. :(

I don't know if it helps to remind that X-mirror works along the x-axis. Your character would need to face negative Y to take advantage of that. And Object>Apply>Rotation also.

Okay, thanks. I’ll try that and see.

Okay, something still isn't right. I wish I could upload a save... :-\ From what it looks like to me, the model is facing negative Y anyway, but it still isn't working. If I adjust the rotation on the Y axis however, the character rotates around clockwise/anti-clockwise from the centre of the grid. Rotating on the Z axis spins him around so he either faces towards the screen or has his back to it.


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Copying keyframes from one project/rig to another
How do you go about copying the keyframes from one project/rig/object to another. Baring in mind, that my rigs are in totally different saved files. The character I'm working on is basically the same as my other, except the character has been modified - squashed inwards so they're thinner, characteristics altered/added etc. So it uses the same armature as well. However, though I did delete it at the start, I'd like to transfer my first character's walk animation to my second just to see what it's like, alter it, and save time. I have read you're supposed to select the object, hold Shift, select the armature, press Ctrl + L and then select 'Animation Data'...? I can't find this option anywhere. I've also tried selecting all the keyframes from one rig, copying them, and then pasting them into the new one, but it doesn't work. How could I do this?
Thanks

You can always append your old armature and/or actions into the new file. (Shift F1)

Didn't think of that. Will give that a try now. Thanks.

That doesn't appear to be doing anything; it doesn't appear in my current scene, or if I start a new one.

Importing individual animations seems to work though, so there's that. :)

You should be able to import the whole model including all it's animation strips that are in the Dopesheet so I'll ask the obvious - have you copy pasted the model into the new project from the appended scene? (CTL-C & CTL-V)

It’s not the entire model and its animations I was after though - just the keyframes or a single animation. But appending individual animations works for me. :)

Actually, I had in mind that you'd delete the appended model and scene once you've copied the anim strips across to the new project's model.  You've got it sorted anyway, so that's always good.


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Weird Leg Problem
For some reason the legs of my model act weird whenever I move the hips or root bone downwards. My character's legs cross over each other as though he needs to the loo lol. I don't understand what's happened as everything is pretty much the same when I started the Weight Painting; nothing seems out of place.

You need to bend the knees a bit, in Edit mode, so that Blender understands how they are supposed to bend. Also, I think you should parent the feet and hands controllers to your roots so that it also follows, but that's another topic...

And as simple as that... Thank you. :D
What, is that for every controller bone to the root bone?

You need one bone to control your whole armature, it looks like in your case, "C_root" is supposed to be the root bone


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How to extrude rounded and smooth?
I have a following problem: I have a sphere and I want to extrude particles out of it like so:

But I want the extrusion to be rounded like in this picture:
What kind of settings do I miss please?

I dont know where that lower image comes from but I guess he is using subsurface modifier (press Strg+2)

I think this is it. But when I use it it applies on my whole object.  How to apply it only on my extruded one?

W -> Smooth Subdivide? Isnt quite the same but I think it will do what you want

You can't apply a subsurf to part of an object, but you can control the way it subdivides.  Consider this object

If I apply the subsurf I get

It solves your problem by rounding, but it rounds where you don't want it to. There are several ways to fix this, depending on your need.  Here are a couple.
You can bevel edges and control how the rounding happens, perhaps making it less obvious

Select edges you want to control

Enter CTRL-B. The cursor will change.  Moving it controls the width of the bevel. Rotating the scroll wheel controls the number of steps

You can use the bevel modifier to accomplish the same thing but with more control.
You can create edge loops.  Consider the base of the extrusions. Enter CTRL-R. Place your cursor near the base of it until a red line appears around the extrusion

Left-Click and then move the line where you want it
Left-Click again.
My example would require a lot of edge loops or a lot of bevels. Here's a version with all of the edge loops selected.


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Objects hides when drawing in full size

Objects partially hides when are modeled in full size. These ar 900mm high. It happens in every view.

you may have pressed CTRL+B instead of B when tryed to select. this clips the wiew to the rectangle area you draw after the keystroke. Try CTRL+B again to remove it.


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import 3ds files in Blender 2.80
I see there is no option for importing 3ds files in the File -> Import menu in Blender 2.80.
Does this mean importing 3ds files will no longer be supported in Blender?

The last I checked a daily build, 3ds import was broken. I believe that the beta has removed any addon that has obvious problems.  I would guess that 3ds import will be fixed eventually, but I've not found any official statement to that effect.

This is answered here: https://blender.stackexchange.com/a/215548/119206

The best solution I've seen so far is to open ver. 2.79, import the 3ds file in that, then copy and paste the entire screen to ver. 2.8.  You can then save to a .blend or .dae or .obj file from that.

You can also copy paste instead of saving it and opening it :)

Like any other import/export tool of Blender, 3DS import-export is an addon, and need to be ported to Blender 2.8. If it hasn't been done, then it's unavailable until someone takes the job.

I also got that , but there's something you can do about it , if you still got the last blender version 2.79 , you have to export the 3DS file into it in a new blender project and save it , go to blender 2.8 and go to append and find where you saved the project with a 3DS file and load it


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Blender 2.8 (Shading/Textured Solid)

Hello,
Dropping into 2.8 as noted in another thread and trying to get to grips with the new interface. There is one thing I am having hard finding, or finding the equivalent of and that is the "Textured Solid" option.
I would really appreciate the help :)

You'll find some answers here:
https://www.youtube.com/watch?v=ydgpVmsQAIM
(to switch to the shaders view, click the 'shading' tab on the upper part of the screen/window)

Unfortunately Blender Render has been completely removed in Blender 2.8, so this functionality is no longer available.
Could't agree more about having to use materials slowing down my workflow when I'm going to be exporting to something that completely ignores the materials anyway.
However there are at least ways of speeding the process up, and you can still get the same visual feel as Textured Solid.
The button to the right of the colour option lets you quickly pick a new input node type while avoiding the node editor. So you can quickly switch to an image like this:

Then just select the image with the dropdown that appears.
You can get a similar visual feel as "Textured Solid" in the viewport by setting your shading up like this:

(I have both of these set up this way in my startup file. Then when I need to add a new texture, I just duplicate the material and change the texture.)

Not there is not. It's a Blender Internal thing and was already gone with Cycles. Set the viewport's shading to lookdev and it will do:

The problem then becomes speed and accessibility.
Whereas before in 2.7

Unwrap model
Load texture in UV editor
Model now shows the material.

2.8

Unwrap model
Make a material
Set up nodes to use bitmap texture
Apply material to the model
Make a material and nodes for each and every model.

Now, this is fine if you work is to  be rendered in Blender, but I work in a game engine and want to spend as little time as possible within Blender's material system. Not to mention I now have to deal with another panel entirely in my workspace, the node system


text:
2.8 Basic Unwrap Problem?
https://www.youtube.com/watch?v=0trhFMBdVzI&feature=youtu.be
Video of the problem
Right, so I have a problem. I just downloaded 2.8beta and I can't unwrap anything it seems. Unless I am completely misunderstanding a new workflow.
Seems when I try to unwrap something, it doesn't appear inside the UV editor.
And whenever I try to open a side panel or do anything there I get a message that reads
Tool 'Select Box' not found for space 'IMAGE_EDITOR'.

In 2.8 where is new View mode in uv/image editor.
In this mode where is no UVs or mask or painting tools are display. To edit UV you need to switch to UV edit mode:

New View mode is good for viewing image for reference.
Note, that where is new UV editing workspace with uv/image editor with uv edit mode by default:

Tool 'Select Box' not found for space 'IMAGE_EDITOR' it is just a warning don't pay attention to it.

The UV Editor is now its own editor in the editors menu, not a mode of the image editor.


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How can I increase my UV unwrap Resolution?
My apologies if this is an odd question but I recently created several image/textures in my UV editor in Blender in order to paint my textures onto them. This has been going well but I have realized my resolution is too low to draw the thinner lines I want to and not have them begin wobbling or cutting out sharply.
I know I could create new versions but I thought I might as well ask.
Is there a way to increase the images Resolution inside Blender?

Suggestion.  Start Fresh with higher resolution images.  The sooner the better.

you could increase the resolution in Photoshop then re-import and re-work what needs to be in Blender

@atomicbezierslinger
Thanks both of you for the feedback both of you, I'll follow one of these paths.

@moonboots Thanks both of you for the feedback both of you, I'll follow one of these paths.


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Disappearing bone shapes with rigify (show_wire)
In the transition of 2.79 to 2.8 there are currently still some problems. The main problem I'm having is, now I can't see my wire shapes without manually selecting "show wireframe" on all of my bones.
I know this is going to happen so I'd like to automate it.
Is there a simple script that can turn wireframe on or off on all selected pose bones?

You don't need a script, simply hold Alt when clicking the checkbox, it should do the action on the whole selection. Unless this function is broken in your 2.8 build of course x)

Holy jeez, you can do that with everything too? That's useful, thanks!

Almost everything, yes ;)
Don't forget to vote up if my answer did help you.


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Calculate 2.5D point cloud from scene
Ich would like to generate a 2.5D point cloud of a scene from the camera's perspective with python. Let's say the camera has a rosolution of [n,m] pixel and as a result I want to have  n*m 3D vectors each starting at the camera and pointing to the surface of the object. I don't expect any code, but please point me in the right direction.

you could just render the image and take the Z-Depth. From that Z-Depth image you can easily get everything you want (with some coding of course)

@HenrikD: thanks that works. See also:
https://blender.stackexchange.com/questions/105094/get-a-full-numeric-z-depth-from-a-rendered-image


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Fire appears in preview, only renders emission
Recently while trying to render fire I run into a problem where the fire shows up in preview but it does not render, only the light that comes from it.

All the settings are at default, I can't seem to find what is causing this as I was perfectly able to render fire before.

I recently had a similiar problem. Your render, in fact, is correct, but the result is displayed incorrectly. This is due to the way alpha is represented in the viewer, which uses straight alpha rather than premultiplied, so emissive volumes like fire can't be properly modelled. For a detailed explanation, see this answer.
To see the fire, just try switching to RGB mode instead of RGBA in the image viewer and you'll see the flames:

As suggested in the linked answer, a solution would be to use an EXR image wich has premultiplied alpha. If you can't use an EXR however, you need to convert the premultiplied alpha to straight alpha in the compositor, then save as e.g. PNG:

when using the premultiplied alpha node the fire still isn't there, am I doing something wrong?

Are you using the "Premultiplied to Straight" setting? Is your render up to date (F12), and is the fire visible in the current animation frame (switch to rendered mode)?

@Ignatiamus is absolutely correct here. Unassociated (straight) alpha has no place in a compositing pipeline. The fact that Blender screws this up is part of the problem. Get rid of that convert alpha node, and spread the word about The One True Alpha. ;)

I also have this problem every now and then. For me neither solutions worked, the converter nor the EXR render.
For the people that also can't do those two things. I simply rendered out an emission pass (for animation).
In 2.8 that is easily done.


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how do I delete an add-on in 2.79?
I installed an add-on, it didn't show up so I restarted Blender. It still didn't show up so I thought I'd load it again (I didn't check to see if it was in the add-on list). What happened is shown in the attached image.

Try going to both of the directories and just remove the files completely. Then try installing it again to the Blender Foundation directory, checking every time if the add-on is visible in the list.
Edit: as batFINGER said, deleting the Users...\measureit folder would also suffice presuming that is you main blender directory.

Removing the Users/..../measureit folder  would suffice.

True, but it it confusing how they got the add-on to two different blender directories.

No it isn't.  Addons bundled with blender are in [version]/scripts/addons folder  of the  folder containing blender executable.  Addons installed manually by users in the Users folder.

Thank you, I feel stupid that I hadn't thought to go to the Blender directory. Thank you for your responses and for taking the time for me. Cheers


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How to listen to UI element change or selection state?
I can’t figure out how to add listeners to dropdowns in UI panels.
I copied some example of dropdown to select an Action:
# picker dropdown to pick Pose library
if bpy.context.object.animation_data is not None:
     self.layout.prop(bpy.context.object.animation_data, "action")

So far I've had to create a button/operator, clicking this button will update UI List view to match dropdown selected Pose Library.
But I’d like to get some method to listen to selection from this drop down.
When user selects pose library A, I’ll show a list containing all the poses from library A and so on.
Any help/links appreciated!

You can check the selection in the panel's draw function and display the poses accordingly.

Thanks. Will try that.


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How to set active Pose Library selection from Python (for running ops)
(I also asked this on Blender Artists)
I’m trying to run:
bpy.ops.poselib.apply_pose(pose_index=index)

For some reason I can’t seem to be able to find way to set active pose action to be able to run this.
I’ve found how to get access to current action (I think):
context.object.animation_data.action = bpy.data.actions.get(sel)

But it isn’t the same thing. Doing this does work for selecting action, it sets current action in Dope sheet BUT it doesn’t set it in Properties window’s Pose panel… rendering it useless.
I would need to be able to set the actual Properties window Pose Library panel selection.
If I run ops code with incorrect Pose Window selection, it just fails …but if I change target pose library manually, it works.
One would think that if ops exists, there has to be a way to also select which one of Pose Libraries to target.
Any help appreciated!

Consider using context.object.pose_library = action  to set the pose library, and obj.pose_library.pose_markers.active_index = pose_index to set active marker (ie the pose_index in apply pose) `Related  (possible duplicate q/a)  https://blender.stackexchange.com/questions/58595/how-to-change-a-pose-lib-using-script

Thanks. I did do several searches before asking, for example "python set pose library" doesn't find thread you linked. I find StackExchange search to be not so good. Will bookmark that thread too.

Agreed re searching on this site, can be very hit and miss.  Putting "[python]" in search term looks for questions tagged python.  Google site search , eg "site:blender.stackexchange.com python [search words]".  is often more productive.  Will close as dupe.


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Hair physics and/or particle edit with particles rendered as objects
I'm trying to make a creature with feathers and therefore will be rendering hair particles as an object. However, I would like the particles to be able to be combed/ react to gravity ect. It seems like you can only do such things when the hair particles are rendered as strands. Is that true?

Figured it out, I've just got to bake the simulation before I change the render type to object.


text:
How do you add single free floating vertices as primitives at a given XYZ coordinate postion
I am sure this question has been asked before but I have searched and searched and I can't find it (I even vaguely remember asking it in 2013 5 years ago).
I am easily fooled by perspective illusions, and prefer to plot rather than to sculpt, in 3D, because of this.
Is there a way I can make single vertices a primitive in the primitives menu, like that darn monkey (long live suzie), so that I can place a bunch of points in a row with minimum effort, and then connect them and create edges and faces at the end?
I vaguely remember reading about a potential plug-in solution, but that was quiet a while ago, and I can't find my source, so I'm totally lost

Keyboard shortcuts are pain in the wrists man

Is this what you're looking for? https://blender.stackexchange.com/a/43097/599

Maybe, I just saw your response, Imma click it now get I'll back to you shortly

If you want to avoid all the other stuff which comes with the extra objects addon, you could also try making your own single vertex primitive: https://blender.stackexchange.com/q/8275/599

No. I don't want it on the cursor position, I want a box where I can type in 3 coordinates and press enter to create vertex there, and then it clears and lets me start typing another point. So that I can create a whole bunch in one go.

Umm I instinctively format my text and hit 'enter' early, so that comment was not ready for being shared, too late now, I'm kicking myself

I was gonna ask if (cos my memory of primitives is still from 2013 and might be faulty) there was anything like that; or if there was a path I could take to code it myself? I don't know python, but I can soldier through if I have lots of reference material, I guess.               ----- I do have C++ experience and am good at following tutorials

hehe, you can still edit for something like 3 minutes, go! (also shift+enter lets you put newlines in,
but they won't be rendered)

(Response: Yeah, but sometimes I spend a bit typing, plus I was half finished anyways so bfd in the grand scheme, just "-whoops-" is all I meant by it)

This link you shared might be exactly what I was looking for, thank you so much! " blender.stackexchange.com/a/43097/599 " but the mass production point plotting box still sounds fun... ...... ...hmm...

I don't know if any existing way to get a textbox based workflow like that, no. But it definitely sounds possible to implement with an addon. If you are familiar with coding at all it should be very doable. There are some useful example scripts accessible in Templates > Python in the text editor.

Also, this addon, especially bit about creating a property dialog, may be a useful example. And of course, feel free to ask a new question for any addon-implementing questions you run into :)

It was the Extra Objects addon.
I was going to use it to create a point primitive, so I misrembered it and used the wrong keyterms while searching for it.
I did have a neat/convenient idea while trying to figure this one out, I'm not sure if that's a seperate question or just an alternate solution though (about the point plotting box).
So if something like that exists [the enmasse point plotting box], feel free to comment it to me, if it doesn't then I guess I'll have to ask/or/find some more questions later [about making plugins, and creating a tiny little app/menu for that in blender]


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Can and how: do you bend a mesh with a skeleton, but then remove the skeleton and have it remain bent?
Using a tube as an example:
If I make a cylinder and subdivide it into lots of tris,
Then add a skeleton and bend it to make it look more organic.
Is there a way to remove the skeleton afterwards but retain the 3D dimensional distortion?
I ask because I want to model houseplants and this would make my life so much easier if it were possible, with the stems and whatnot.
I also think I may have performed this by accident while rigging my first characters, but since it was on accident I have no idea how to consistently or if I can even: replicate it.
Thank you in advanced for your help.
Also I'm not sure which categories this question belongs in, but I did my best, sorry in advanced

Go to the armature modifier on your mesh. Press "Apply".

In other words:   I'm looking for a way to abuse the rigging tools as sculpting tools instead, because they can pretty easily make some pretty gnarly shapes, but then those shapes aren't very useful if there is no way to fundementally bake them into the geometry of the mesh.    I want to take a stick, bend it with a skeleton in pose mode, and then somehow convert it into a primitive, with the new shape, created from the pose, but, without the skeleton, and then use that primitive as a piece in future more complicated models

Leander, I just saw your comment, this post was near the bottom of a checklist in my head and was added to that checklist about a year and a half ago, when I was playing with blender, I'm pretty sure your solution will work since it sounds about right, but I am informing you that since blender isn't currently open infront of me, it will be between a few hours and a day before I manage to test out the solution to verify it.  But... I will definitely get to it soon, my creative urges have been firing up and I badly want to make something.  I can't wait to test this out, thank you so much!


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How do i remove noise?
I tried to make this scene from blender guro tutorial, but i got problem in my lamp which is to noisy. Is there a solution without increasing my samples render?
Im beginner for this stuff.

BlenderGuru has made an article on this topic, "7 Ways to Get Rid of Fireflies Once and For All": https://www.blenderguru.com/articles/7-ways-get-rid-fireflies

Also see https://blender.stackexchange.com/questions/84322/how-to-reduce-noise-in-really-dark-scene

Use the denoising feature in Blender 2.79.
The noise might be caused by a glass material in your scene so I recommend deleting the object with the glass shader.

Thank you for answering my question, now i fix the problem.


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Pull Apart Educational Model
Is it still possible to make a model that I can export to somewhere and when viewed the user can interact by clicking on certain items for them to be hidden? I'd have thought the game engineer would have done that but I know that's been removed, it'd be nice if I didn't need to ship it to unity first.
cheers

Related https://blender.stackexchange.com/questions/53919/using-blender-game-engine-for-vr-360-tour-on-mobile-is-it-doable

So here is how you would do this using game logic. (The blend file at the end if you want to skip my explanation).
1) Connect an Always sensor to a Mouse actuator (the default state of this actuator is to make the mouse visible so you shouldn't have to change anything).
2) Where the yellow box is add a Boolean property and make sure it's starting state is True (checked).
3) Add two mouse sensors (as seen in the light blue box). Set one to Mouse Over and the other to Left Button. Connect both sensors to the same controller and make sure it is set to Add (that is the default). Now connect the Add controller to a Property actuator set to toggle the property you created in step 2 (see the dark blue box).
4) Add a Property sensor and set it to Equal "True" then connect it to a Visibility actuator in which Visible is checked.
5) Add a Property sensor and set it to Equal "False" then connect it to a Visibility actuator in which Visible is unchecked and Occlusion is checked.


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Auto baking the indirect lighting of irradiance volumes with animation?
I've searched forums, Google, and YouTube for a way to use Eevee's  irradiance volumes with animation (moving objects), and haven't found any solutions, or even a mention of this. Maybe I'm using the wrong search terms.
In short, when using irradiance volumes and Eevee, indirect lighting doesn't recalculate between animation frames when it's baked, and it doesn't render at all when it's not baked. Checking 'Auto Bake' in the Indirect Lighting tab seems to only have an effect when I manually change the settings on an irradiance volume.
Can irradiance volumes be used with moving objects?
Your help would be appreciated.

It is not yet supported with moving objects (e.g. animated mesh lights).

According to Blender at
https://docs.blender.org/manual/en/latest/render/eevee/render_settings/indirect_lighting.html in paragraph 3:

As of now the light cache is static and needs to be computed before rendering. It cannot be updated per frame (unless via scripting). This limitation is being worked on and will be removed in future versions.

Same, i need to render animation with a screen emitting light each frame, and i believed auto bake would work but it doesn't update each frames

Now 2023 and Blender 3.6 still has not added this simple feature, when should we expect the "limitation" will be removed? Or is there another reason this is not being added?


text:
Applying the modifiers to my mesh messed up the model
I have a applied 3 different modifiers to my mesh, and this is the result I'm getting. Any Idea what's causing this problem? I have shrinkwrap, Boolean modifier, and Subdivision. When I choose all and removed doubles, its erasing faces as well.

can you provide your blend file ?

Here it is:

i am sorry, but i don't get it. What do you want to achieve? your topology is clean. I just moved your objects a bit and deleted the shrinkwrap (i don't know what you want to achieve with that!?) and your topology is looking good...[1]: https://i.sstatic.net/otCnx.png

I want to solidify it, make it more thick.


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Shrinkwrapping has some pinching
I'm shrink-wrapping and getting some pinching. My guide mesh has triple the amount of faces, so the detailed mesh can shrink-wrap on it. But where the holes are there is some obvious distortion. And some lines which appear where the bumper is.

subdivide the guide mesh

Thanks for that!
I was following an old tutorial, and I the layers panel isn't available in the tutorial, because its an outdated interface.

Is there anything called "Layers panel" in Blender? There is "View Layer" panel in the Properties editor, View Layer Properties tab, but what does it have to do with anything?

Yes my mistake its the view layers panel not layers panel, I got confused with photoshop. But some people do refer to it also as layers panel, because its heavily influenced by Photoshop which lots of Blender artist are using.
https://ibb.co/0MGySDM


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UV unwrap from Blender to Substance Painter
I have unwrapped an object, of a sphere, and the unwrapping looks clean. I applied a colour grid to see how it lays out across the mesh, which looks correct. But when I apply a texture from Substance painter, that particular section looks stretched. Is this a Substance Painter issue, or the UV unwrap is wrong?

That UV map looks like a map of the default cube that was used to model your object. Are you sure that you've actually unwrapped the object since you modelled it?

Your UV from the first image do have some stretching. You can notice that in the 4, the H and the lines above the H. Make sure that your unwrap is using the subdivision modifier

This is the method I have done.
https://ibb.co/jvBrgdH
Ill provide the file as well.


text:
Is it possible to animate curves profiles
Is it possible to animate the properties of curved profiles?

Not directly, unless I'm mistaken.. it's still just primitive creation? Could you give us an idea of the final effect you want to achieve?

I use the screw modifier for some masking methods, put it takes a few more clicks to achieve the results, but these primitive shapes, have much more creative options, so I was wondering if it was possible to animate some of their properties. But since it's not plausible, I'll stick to my usual method. Regards. :)

I'm sure there will be a GN solution, if otherwise it's a bit fiddly..


text:
some parts of the cloth simulation are protruding once collided with object
the cloth on some parts seems to be protruding once it collides with the object(Cube).

A screenshot of your cloth settings would have been helpful... have you enabled Self Collisions to prevent the cloth from intersecting itself?

That's what was missing. Cheers.

Well, it is disabled by default (I guess for performance reasons) but in almost every tutorial on cloth simulation it is among the first things that get changed in the cloth properties  :D


text:
unable to subdivide the mesh
I select the mesh to unsubdivide, but this method is not doing working, what am I doing incorrect?

On that object, try Mesh > Cleanup > Limited Dissolve.

Have a look here for more info https://blender.stackexchange.com/questions/155453/unsubdivide-doesnt-work

Un-Subdivide will work on quads, not tris

If you want to simplify the objects geometry and it is all triangles, one option is to use the Decimate modifier set to Planar.
Both object in the screenshot are have the same geometry but the one in the front has the Decimate modifier on it.


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How can I make a rug carpet fringe on the edge of my mesh
How can I make this carpet-rug fringe on the sides on my mesh?


text:
Eevee film grain type filter?
I have been searching on Google if there is any scratches/film grain type filter for Eevee while in realtime? Is this kind of filter even possible in Eevee. I have seen it done in game engines. Or would I just have to render the scene and do it in post production as I normally do.
Thanks, James.

There's currently no way to emulate film grain without the compositor.
This is obviously a crude workaround, but you could find a film grain image sequence or video, (or somehow make one procedurally using nodes), and use it as an alpha texture for a plane. Then, constrain the plane's rotation and location to always be right in front of the camera. This wouldn't work if you need Depth of Field, but it would probably work ok if you didn't use DoF.

Thanks thats a good idea, I will try it.


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How to animate a surface that only emits light when touched by object?
I'm trying to find a way to make a surface (or object) that sort of "reacts" to touch/collision by emitting glowing light around that touched area. Best example would be the scenes in James Camerons "Avatar" where they run through the forrests full of reactive bioluminescenting plants. Basically I need it for an architectural project where I want to add that pressure sensitive light emission feature to stair surfaces to make them interactive and more attractive for the employees to use. Need to make an animation of that under the bottom line. Ideas anyone? Keyframing when touched seems to be a bit unauthentic/ineffective.

Dynamic Paint might be helpful here: the map created by it could be used to control a mix to an emissive  shader. I'll flesh this out when I get a chance, or someone else might come along sooner..

Set up your reactive surfaces as a Canvas for Dynamic Paint, and your contact surfaces as Brushes.
You can store the effects of the brush on the canvas either as vertex data or as a a UV-mapped image.
In this example, The steps were UV unwrapped, and a wetmap was baked as an image sequence, which was then used as the factor to mix between a diffuse and emissive shader in the steps' material. The wetmap was set to fade after about 40 frames. On the whole, the tools guide you through their use; I can't think of any major gotchas.
The Canvas (Steps) was set up like this:

The Brush like this:

I baked out the maps using the 'Bake Image Seqence' button in the 'Canvas' panel.
You can use the image sequence as a mask. something like this:

And this is the sort of result -

The method given here bakes the paint result to image-maps, on the assumption that you won't want a highly subdivided model in your architectural render. However, to preview the effects of the various settings, it would be better to make a highly subdivided test-bed canvas, (a plane will do) and set up a simple brush, say a sphere. Then set the 'Format' in the canvas to 'Vertex', and the mode to 'Paint'. Then by having the animation set to continuous looped playback in the timeline, and moving the brush with respect to the canvas, you can see the effects of settings live in the viewport.
I would suggest you want to select 'Wetmap' as the preview in the Output sub-panel, and play with 'Spread' and 'Shrink' effect speeds, and 'Drying' and 'Dissolve' times in the Advanced panel. Also adjust the initial 'Wetness' (load) of the brush. These will all interact to give a variety of organic feels to the animation.
Don't forget, either, that the wetmap can wind up being used to mask a variety of other effects in the material of your steps, including, for example, other textures, which may themselves be animated. The results can also be used to control particle systems.

This looks pretty much like what I imagined, thank you!! You do have an idea how to make this effect even more organic looking? I'm going after bioluminescence that looks really "alive", so is there a way to make it flickering/ growing wider/ ... I'm open for more creative input. Again, massive thank you so far!

@Niklas   (See edit)... This is a very open-ended request :) In the edit, I've suggested a route for your own exploration, ( which doesn't even start on the possibilities offered by, say, particle systems, and so on..) If you find you want a specific effect, I would suggest posting another question along the lines of: 'How do I get Dynamic Paint to do this? Or is there a better way?'

Perhaps you could use animation nodes?

Here I have a blender sphere activating the light of another sphere when it gets close enough. Don't be intimidated by all the math nodes! It is just to get the timing right. The reason I subtract by 0.49 is because the radius of the sphere is 0.50. So, when the two spheres are near enough (within 0.10 blender units) of each other, then the emission will go to 1. If not, then the value is too small and the rounding functions keeps emission at 0. The "value" is the inverse of the proximity/distance between the spheres.
This is the blender file.
Do you want the light to stay on once touched? Perhaps have a 10 second delay and if it's not touched again, to turn off?
Let me know more details and I can make a better set up.

Thanks a lot my friend, wasn't expecting an answer that quick. I'll work it through and let you guys know about the progress.


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How to animate a glowing surface with radial color gradient that fades out after short while? Bioluminescence / "Avatar Effect"?
how do I animate glowing foot prints that fade out after a few seconds? I created this animation of a person walking up a set of stairs and would like to add the mensioned effect, like in James Cameron's Avatar.

Basically I was thinking about adding a light emitting surface around the foot that sort of begins to glow violette in its center when the foot touches it and then fades out to its edges with a darker blue after the foot left.
I would be willing to animate it frame by frame to avoid anything like dynamic paint.
Anyone an idea? Thank you!

What about using empties hooked to the feet. The floor material uses a Mix Shader to activate Emission with a Factor based on a Gradient mapped to an Object UV, specifically the Empty. The glow would predict the foot fall but also drift and fade as the foot steps away.

Thanks for your answer, but unfortunately I struggle with actually setting the nodes up due to lack of knowledge. Could you post a picture of a simple setup of what you try to explain? Especially as I don't quite understand what you mean by mapping something to an empty. Cheers.


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Change color of part of object inside mesh
I have a complex bezier curve in blender using the Cycles engine that loops in and out of different mesh objects.
The curve has a simple diffuse material and the mesh would normally be invisible (or completely transparent). What I would look is for the parts of the curve that are inside a mesh to be a different color (say white outside, red inside) and preferably even for this to be a different color for different meshes. Notably I would like the parts of the curve that are behind the mesh (from the perspective of the camera) to be the normal. I understand that somethings like this can be achieved with a complex setup of boolean modifiers but I was hoping there was a more flexible way to do this.
Any help would be greatly appreciated!

Can you create a sketch or a mock-up? There seems to be a lot of requirements there.


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Can't use dyntopo in sculpt mode
I'm working on creating a 3D creature using a cube as a base.  I've got the low poly version of the character created and am looking to use the sculpt brushes to enhance it.  However, I'm getting an error when I try to apply the dyntopo feature.  "Generative Modifier Detected.  Keeping modifiers will increase polycount"
I've tried to remove the modifiers to use dyntopo but that threw off the modeling I've already done.
Any ideas would be helpful and appreciated.
Thank you

What you see is actually a warning not an error, it will allow you to continue on but you may get odd results when you leave sculpt mode.
If you have modifiers that generate part of your model, like a mirror or skin modifier, you want to apply these modifiers, this will turn the generated data into real geometry that you can sculpt with.
For other modifiers like a subsurf, you will still get this warning, but it is better to remove the modifier, sculpt and then replace it if desired.
To apply modifiers, you should start at the top and click apply to remove each one you want to keep the results from.


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What's up with this model?
So, I was importing a model from Mario Odyssey into Blender, when this happened:
Is there any way to explain this?

https://blender.meta.stackexchange.com/questions/2449/what-is-the-problem-with-posting-an-image-or-link-and-asking-how-do-i-do-this

It would be easier to see with the blend file here... but looks like all the bones in the Character are aligned to the normals.
Look in the Outliner if you can separte it from the geometry and try to build a armature scheme native from blender.

The rig for this model was not really designed to look good in Blender—it was probably created in Maya or something. This is what's creating the strange appearance. You have a few options:
1) Delete the rig and create your own from scratch. Just hit X to delete the rig.
2) Manually fix every single bone to look good. (This will take extensive time and effort for potentially little reward.)
3) Deal with it. Just play around with it a little until you figure out the rhyme and reason behind the rig. Get used to it, and then use it all you like.


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Mirror not work correctly for stl imported file
I have a troubleshoot with my blender file. I've upload a stl file in blender and when i apply a mirror modify to X axis i see 2 objects. I tried to change 3d cursor position, but not work.

By mirroring you don't get two different objects; it's still the same. The point on which your object is mirrored is not the 3D cursor but the origin of the object.

Change the Origin
If you want so set the origin to a specific point, mark the point with the 3D cursor, where you want to set it. Then hit Ctrl-Shift-Ctrl-C and click on Origin to 3D Cursor.

Alternative Way without changing the origin
One property of the Mirror modifier is called Mirror Object. Instead of mirroring the object at its own origin it will use the chosen object's.


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Body part recognition inside of blender using a neural net
So I'm working on a project that's turning out to be monstrously difficult. I'm trying to automate the rigging process inside of blender using the addon "Auto-rig pro". This addon has a feature called smart rig that automatically places a skeleton into a mesh. Using this I've been able to automate everything but one step.
In order for the rig to be created automatically you have to manually place markers on the neck, chin, shoulders, wrists, ankles, and groin. If you've ever used mixamo's autorigger it's basically just that. So in order to fully automate the rigging process I've resorted to using a neural net.
I've been doing a lot of research on machine learning, but unfortunately it appears that I'm the first to attempt something like this (as far as I know). After significant effort I've managed to install Tensorflow and Keras into blender, but I start running into problems when I try to figure out how to feed the data to the neural net.
Normally a neural net is fed raw images, but I need to feed it the 3d view. The marker placement is done in a straight on orthographic view, so I only have to worry about 2 dimensions here which is nice. I could render each model as an image and input it into the neural network, then have the neural net output the appropriate marker coordinates, but rendering takes time and this method seems somewhat unreliable.
Honestly I'm feeling pretty damn overwhelmed by this whole process, I'd never written anything in python until a few days ago, and I've never tried to make a neural net do anything more sophisticated than recognizing simple number patterns.
If you have any suggestions or ideas at all I'd love to hear them and I'm happy to answer any questions you have. Just feeling like anyone other than myself is considering this problem would mean a lot to me.
Also I apologize for any typos/grammatical errors I may have made. After working on this whole neural net dilemma for 8 hours straight my brain is pretty much completely fried.

Consider this to your approach:

feeding your net just a 2d image is limiting (and more work to set it up) when you could feed it whole 3d mesh. You could even build an octree and know what is where in space and feed this to the neural net, basically voxel data instead of pixels
probably the whole neural net thing is not even necessary. There is a popular method of extracting skeletons from meshes by Laplacian smoothing the mesh: Skeleton Extraction by Mesh Contraction:

  Our method extracts a 1D skeletal shape by performing geometry contraction using constrained Laplacian smoothing.

You will find this in open source C++ CGAL library here. This is probably enough to know where the neck and crotch is and where limbs end.
other method is: Mean Curvature Skeletons:

Code here.

You probably want to Access Render Result pixels from a script.
From that question, there are two possible methods, which both result in a numpy image which you can feed to tensorflow. You will probably have to reshape it since tensorflow excepts a non standard shape.
Create an orthographic camera directed at your model.
This first method utilizes the Viewer Node Hack. With it, we can't use opengl, but in my test Blender Render could be setup to run very quickly. I display the image at the end with opencv2, but that wouldn't be necessary.

Create a Renderlayer and connect it to the viewer node.
Render the image.
Read the pixels from the image "Viewer Node"
Convert the image to an 8bit bitmap in the $[0, 255]$ range. (Note, that this image will not have any color transformation and will correspond to the RAW setting of Blenders color management.)

The second method works with opengl, but requires saving the image and opening it. We can't use the Viewer Node Hack, because the OpenGL render does not get Postprocessed with Compositing.

Render the image with opengl.
Save the "Render Result" image
Open the image with a python module like Pillow or opencv.

Both methods use rendering, but it can probably be setup to be quick enough. My non-optimized renders took less than 0.4s.

1st method
import bpy
import numpy as np

bpy.context.scene.use_nodes = True
tree = bpy.context.scene.node_tree
links = tree.links

for n in tree.nodes:
    tree.nodes.remove(n)

rl = tree.nodes.new('CompositorNodeRLayers')
v = tree.nodes.new('CompositorNodeViewer')
v.use_alpha = False

links.new(rl.outputs[0], v.inputs[0])  # link Image output to Viewer input

render = bpy.context.scene.render
render.resolution_percentage = 100
bpy.ops.render.render()

# get viewer pixels
viewer_image = bpy.data.images['Viewer Node']
pixels = viewer_image.pixels

arr = np.array(pixels[:])
arr = arr.reshape(render.resolution_y, render.resolution_x, 4)
arr = np.flipud(arr)
# at this point the image is loaded into arr in RGBA as 64bit floats

arr*=255                    #convert to 8bit [0, 255]
arr = arr.astype(np.uint8)

# this is just for confirmation, remove if unnecessary
import cv2
bgr = cv2.cvtColor(arr, cv2.COLOR_BGRA2RGBA)
cv2.imshow("img", bgr) # display the image
cv2.waitKey(1)

2nd method
import bpy
import numpy as np
import cv2

bpy.ops.render.opengl()
bpy.data.images["Render Result"].save_render("D:/opengl_render.png")
arr = cv2.imread("D:/opengl_render.png")
cv2.imshow("arr", arr)
cv2.waitKey(1)


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How to import geometry nodes into new file
I have grouped my geometry nodes, and Im trying to import the geo nodes via append, but I dont see the nodes applied to by Bezier curve.

Ill upload the file for better insight.

I think you have to actually select the node tree data block for use, in the Node Editor. It’s that way for all other non-object data blocks.

in your new file go to append -> choose your file -> node tree  -> choose your gn node tree


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Why does subdivision cause deformation - pinching on even subdivided mesh
I have made a shape, with evenly subdivided quads on the surface. I then add the subdivision modifier on my shape, and the quads have hard edges appearing. So 2 questions I hav.e
1)What is one way to avoid problems in the future when approaching this type of modelling?
2)And Shouldn't the subdivision modifier be smoothing out the mesh, rather than making it seem with hard topology on the mesh?

Can you share you .blend please?

the reason is the shrinkwrap modifier. If you disable it and render it, it is smooth

Forgetting the Low-res version for a moment. The Hi-res version which is its shrink-wrap target already shows this tendency towards un-subdivided  face normals. It looks to me as if at least one of levels of the subdiv that resulted in the Hi-res version was 'Simple', not 'Catmull-Clark', resulting in faces being subdivided flat, not interpolated,


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Tank treads wont spin on Z axis using constraint child of settings
I have make tank tracks, did all the necessary with array, and curve modifiers. I also have object constraint child settings. And empty object parented to my Mesh and curve. I enter the settings as the tutorial below shows, but when I rotate the tracks on the Z axis, they do not spin.
In the comments section, some users are saying this depends on the Blender version to function, or it doesn't work maybe on a newer version.
I'm on Blender 3.4.1.

Here's the setting I have entered:

Here's the tutorial:
https://www.youtube.com/watch?v=FqfIfEx5Eb8&ab_channel=GodRayStudio

Works fine in 3.4.1 here. The only thing you would need to change to get your single track to run in the correct direction is select the curve and use R Z 180 rather than rotating the empty.

Hi there, in the tutorial at 04:45sec the tank tracks are spinning slowly, as he's rotating them on the Z axis. Mine are not spinning but remain static as I rotate them.

I managed to make them spin on the Z axis, but as the rotate they expand from each other. Something is happening to the Bezier curves.

I've just done that tutorial from scratch in 3.4.1 and it works fine without any changes. First thing I've noticed is that you've built the whole thing on the Y axis rather than the X axis and you only have one Child of Constraint on each track. Did you rotate the Bezier on the Y axis rather than X after you added it? I'd suggest you start again and follow the tutorial carefully.

You're right it worked. I was making my Mesh on the X axis. Thanks!


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Mesh not rendering correctly with geometry nodes
I have made this cell fracture with geometry nodes, I have set camera to render it, it’s rendering the angle but not the actual fractured mesh. Even if I remove the keyframes its rendering just the block mesh.
Thank you.

i am sorry, but i can only vote to close this question because we have no idea how your node tree looks like or your render settings or your animation.

Hi, @blender breath. Please edit this to give us a clue. By screwing my eyes up, on your top image, I can just tell from the Outliner that 'Cube' carries modifiers and is marked visible in viewport but non-rendering.. does that have anything to do with it? If not, maybe best to share on https://blend-exchange.com/

I figured it out, you can close the question. Thank you.


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Lines appear on mesh after adding shrinkwrap modifier
I'm shrinkwrapping mesh onto the target mesh, but I can see slight lines appearing. I have already added the subsurfaces modifier, which I think caused this issue. Is there any way to fix this?
The mesh Plane.001 has triple the geometry of the mesh plane.

Have you figured out the issue? I'm currently struggling with the same thing.

Try this method, it should help you organise your mesh to avoid pinching, hope it helps.
https://www.youtube.com/watch?v=3rlMzsBWtPY&t=244s


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Different render results and time on every new f12 hit
after i upgraded from Blender 2.79 to 2.79b yesterday in order to use the cpu+gpu feature which btw apparently no longer exists . I tried to notice if there was any difference on the render time of a scene with emission particles flow + blur that i rendered just before, after the upgrade i opened the same untouched file with same Blender parameters (even user preferences), and this is the weirdest part... every time i hit F12 i got a longer render time and it seems like the light trail of the particles is getting longer like if the animation is running. (it's not, it has always been frame 107).
I filled all of the 8 render result slots consecutively with the same frame and i got 8 results (12sec/13/15/20/30/54/1min44/3min) (the more blured it gets or the longer the particle's light trails are, the longer the time it takes to render) and it seems like the time is going up to the infinity as long as i keep rendering the same image, it takes longer and the result is more "changed"... Any idea about the reason it is changing ? thank you and sorry for my bad english.

PC specs:
 - CPU I5-3340
 - GPU GTX 560ti
 - RAM DDR3 1333MHZ 16Gb
 - Motherboard MSI Z77A-G43
 - OS Windows 7 ultimate
Ps: i got the Blur option turned on ofcourse and the shutter set to 1.
no caustics and all light bounces set to 0 and samples set to 100 .

sorry this is my first post here. I forgot to mention that the second image was the 11th try and took more than 20 minutes, and if i restart blender the process also restarts.


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Inside of clothes pop out certain rigged character positions
Don't know how to explain this in words so here's a video showing the issue.
https://youtu.be/AjOcXKPOm4Q
Is there any convenient way to paint out the weight of the bones on the skirt so the inside won't be popping out?
The topology of the inside is almost identical to the outside, so I'm not sure what causes the popping of the inside.

perhaps a Mesh Deform modifier could be the solution: https://www.youtube.com/watch?v=P6s9H8xX7YA    or here: https://www.youtube.com/watch?v=imhTnlKrTOY

To me, it looks like the normals are facing the wrong direction...


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How to make cloth bounce off object onto the floor at stabilise
I have a cloth which is bouncing off the triangle, but when it hits the floor the cloth goes through. I have applied collision modifier to my floor, just as I have applied collision modifier to my triangle shape.

I guess the face normals of the floor are pointing in the wrong direction, because it looks as if this once was the inside of a cube.

if Gordon's advise doesn't help, pls provide blend file

The normals were facing the correct way, I did the file from the beginning, the collision is correct now, but I lost my settings to make the cloth slip off the object and slide onto the floor.

@blenderbreath please don't add details to your question in the comments section. Blend files belong in the original post, so add them there with the [edit] button above

@blenderbreath So is this file related to the original question anymore? The problem was it's falling to the floor. The cloth in the file is neither falling through the floor nor is it the same collision object like the one in the question... Is this actually a new question on how to make cloth slippy?

Sorry, I tried to undo all the steps, go all the way back, but blender didn't allow more than 30 undos, so I made another file. But I'd like to know how to make  the cloth slippery, thank you.


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Anisotropic textures from Substance Painter to Blender
I'm trying to export anisotropic materials. Seems all fine until I load them into Blender and I cannot see the anisotropic texture on my object. I was told to add emissive to the channels to see if it worked but it didn't when I added the textures to my object in blender.
I'm hoping someone can tell me how its possible, because the Adobe forum, no one has replied.

You need to export the Anisotropy Level and Angle as new output maps.
(Anisotropy Angle -> RGB)
(Anisotropy Level -> Grayscale)

Then use those output maps to feed into the Anisotropy and rotation in blender. You may want to add a 'Tangent' node to adjust the radial effect.
You can also use the Anisotropic shader, which I think gives slightly better Aniso lighting effects, but isn't as flexible as Principled:

(Anisotropic BSDF left, Principled BSDF right)

Could this also be applied for EEVEE render engine?

I don't think EEVEE supports the anisotropic shader.  However you could create an export map for the '2D view' and use that to fake it.  I'll add that to the answer.

Hi @blenderbreath :). Robin Betts will probably know  https://blender.stackexchange.com/a/168190/78972

Hi Jeff, which Alpha is this?
https://postimg.cc/3kVvMjPq

@blenderbreath came from the standard blender BSDF, I think it was Opacity (GrayScale) doesn't really do anything! Swapped image with the key.


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How to make Vine leaves twirling around a branch
Im trying to make leaves go around a spiral (making it look like a branch).
I am using instancing, parenting it to the branch. The leaves are going into the same direction. How can I give the leaves randomness?

Maybe you should use Particles > Hair instead?

Spotted a tutorial on YT! Thanks again!


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How to make liquid simulation from flat surface to eruption
I'm trying to figure out, how it's possible to make a liquid simulation which is flat liquid, and then suddenly erupts making waves. for example on frame 0 the surface is calm flat, and then as I scroll through the timeline the liquid starts to make eruption like a sudden sea storm happened.

did you try making a cube -> as effector/obstacle, and then just move it in the domain?

Yes my cube is set to effector, and the other object as flow. The simulation is fine. The problem I'm having is finding in the settings how to make the liquid from static flat, to making it almost like a sudden splash.
https://ibb.co/ZYWLNkW

I found a tutorial, but I'm confused on a particular section, as he goes too fast. Im missing one objects settings so the effector can make the splash.
https://ibb.co/gStCWdX
also the tutorial where he explains the colliding object is at: 26: 56
https://www.youtube.com/watch?v=ESShqTMvZWU


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How to join or bridge this section
I'm trying to bridge or join the section in the images provided. One pole (RED LINES) is slimmer than the other (CYAN). I tried to bridge and then scale to match the thickness where the handlebar circle mesh is, but I'm getting wrong results. What's the correct method to make the middle mesh join with both of the other meshes giving it a welded look, and keeping the middle mesh correctly scaled to join them.

Can you explain a bit more what you mean by wrong results? What is the problem you have with the result you have on the  bottom screenshot?

if you notice on the bottom screen shot the bridging mesh goes from thick to thin, but it should be one thickness when joining the mesh.

@blenderbreath Well, you said in the question you tried to scale and match the thickness - when you want it to be one thickness then scale it to be one thickness and not different on both ends. Or delete the vertices on the side that's too thin, then select the others and extrude them. Usually the thickness should stay the same then. And whatever you have done to join the mesh on the thick end, you have to do on the other end as well, only adjusted to the correct thickness. A rod with a certain diameter will naturally enclose more of a thin pole than a thick pole.

why don't you just extrude the "hole" from one mesh until it is very close to the other and then bridge it?

Hello Blender Breath, actually your question is the same as this one: https://blender.stackexchange.com/questions/279051/how-to-get-a-smooth-circle-shape-on-a-curved-cylinder-mesh Also, you should better work on a low-poly object with a Subdivision Surface modifier, it will simplify your work


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Camera view white and useless
I did try looking through other answers but couldn't find one the same as my problem. So far I have tried deleting and adding 2 new cameras and even tested the 'camera view' without a camera and still got the same result.
Zooming out achieves nothing at all but zooming in does seem to show something

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.

You accidentally set your cube as the camera object (shortcut Ctrl+Numpad0). To undo it, select your camera in the outliner (expand your collection), then with  the mouse cursor back in the 3D viewport, press Ctrl+Numpad0 again. This often happens because people are trying to snap to the camera (Ctrl+Alt+Numpad0), but the "Alt" fails to engage properly.


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How to meit particles from character without obscuring details like eyes or mouth?
I'm modeling the Dwarf in the Flask and I have tried various methods of emitting particles from the body but they cover the eyes and mouth. This is what it looks like without particles and the image on the left is my source material. Since I'm out of ideas and still learning geometry nodes I figured I'd ask the community how you would create the effect of black particles emitting from the model.

What do you mean you have tried various methods? Have you tried using vertex groups to determine where particles should be emitted? Or duplicating only parts of the mesh which should emit particles and then hiding the emitter in render?

I've tried different sizes, and quantity of particles but I can't achieve this effect that it matches the source.

Size and general quantity do not determine where they are distributed... well, I give two possible methods in my answer below.

Here's how you create the exact same effect as in the anime:

add a cylinder, delete the top and bottom faces, and scale it down on the Z axis. This will be your emitter object.

parent it to the homunculus body and scale it down until it is just under the surface.

add a "Tract to" object constraint to the emitter with the camera as the target. You might have to change the axis settings of the constraint to get the desired result.

Of course you might still have to play with the particle settings since the emitter area is now much smaller.

My answer was about hair because that's what it looked like in the reference. Would have been nice of @EndZz to explain this anime effect to dummys like me who don't  know it and can only judge from what is visible in the question

@GordonBrinkmann The character has a formless, smokey outline, yet at the same time very well defined eye and mouth. I think it's kinda hard to translate into 3D, that's why I adviced the tracking to camera in my answer.

Well, at least my answer still gives some advice on how to emit particles only in certain areas, so it might not be completely useless.

There are two main methods that I would usually use when creating hair with the standard particle system. The first is a more convenient "one-object-solution", the second might be a bit "better" or "cleaner" in some cases in my opinion.
1: Vertex Groups
Vertex groups are a good way for example to limit where hair is distributed or the length of the hair. Let's say you have this object and you want hair only on the blue parts, not the eye in the center:

What you can do is, in Edit Mode select all vertices (or faces) which you want to get hair, in the Object Data Properties tab create a new vertex group by clicking on the + button and then click Assign.

This assigns a Weight to the vertices. By default this value is 1 but you can adjust it with the Weight value slider below the Assign button to give the vertices a different value. But if you would now go into Weight Paint mode, the object would look like this, the red part has a weight of 1, the blue part a weight of 0.

This weight can now be used in the Particle System settings under Vertex Groups. You can for example choose it for Density (which I did in the following screenshot) or Length, in both cases this will result in the eye part showing no hair because either the density or the hair length there is 0, while on the rest of the mesh it is 1 or 100%.

But you do not have to stick to this "on and off" method. When using the group for the Length for example, you can have values between 0 and 1 to change the length of the chair in certain areas (might not be so clearly visble in this shot though):

And since you can have multiple vertex groups on an object with each of them assigning different weights to vertices, you can of course combine them to manipulate density, length and other options independently from each other.
2: Separate Hair Object
The problem with the aforementioned method in my opinion is that you sometimes get hair where you do not want it even though you are limiting it to certain vertex groups. Especially since vertices/edges usually can be part of a face that should have hair and a face that should not, this can lead to hairs poking out where they should not be.
To avoid this, you can simply make a duplicate of the whole object and delete the faces that should be without hair or take the original object and in Edit Mode select the faces that should have hair, duplicate them with Shift+D and right-click immediately so that the duplicate stays in place, then separate the selected by pressing P > Separate > Selection. Now you have a second object with just the future "hair faces".

This is the newly created object, the original one is hidden at the moment. You can now give it a hair particle system without the need to define by vertex groups or anything where the hair should be, since these are only faces that should get hair.

The important thing now is, for this object not to interfere with the original object and avoid weird shading error from Z fighting of overlapping faces etc. that you can disable visibility of the emitter object without having to disable the complete object for viewport or render. In the Particle System settings under Render and Viewport Display you will find the option Show Emitter. If you disable them (especially important for the render later, the viewport might not be so crucial), the base object will no longer be visible and only the hair remains:

Unhiding the original object now shows everything is how it was supposed to be. The disadvantage of this method is, changes of the original mesh will not automatically change the hair mesh. Also if you want to move the original object, the hair object has to be parented to the original. Or if deformed by an armature pose, both objects need to be parented to the armature in the same way. (You could also work with linked duplicates and masking the mesh etc. but it would extend this already long answer much too much, if you would need something like this you should probably ask a new question.)

3: Both methods
Last but not least, a third method if you want to combine the advantages of both main methods, if you think a separate object is good but varying the length with a vertex group is useful too, you can of course use vertex group on a separate hair object as well.


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I rendered the png sequence but the result video is jittery!
I rendered my frames as png, and then imported in Premere Pro, but the video is playing jittery.
My friend changed blender frame rate to 30, is that the problem?
images are HD but video is not clear:
https://youtu.be/-97o-jyDDnY

You should use the Blender video editing mode for exporting videos.

Then press Shift-A to get drop down add-file menu, or click on the "Add" button.
(Sorry about the sloppy arrow. I didn't have enough time to draw a good one)
select the "Image" button and go to the file in the file browser that you want to add frames from, and press A to select all. If you only want to select certain frames, then you can shift click on a frame to select it too.
Now you need to go to the box labeled "Add image strip" in the bottom left corner, and set the frame start/stop to the amount of frames you want to import.
Now select add image strip in the top right corner.
Now you can select the output format like you would normal renders, but instead of exporting as png, you export the animation as a video format. Whatever works for you. Once it is done creating the video, you can watch it in the location you set it to render to. This is Blender's Sequence rendering mode, which is probably best for quick Blender animation videos.

thanks it also helps a little, but I think my camera was moving very fast so that jittery look might be inevitable.

Yes. That was probably the case. If you want, you can re-render the animation at 60 frames a second. That should make the movie smooth.


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Problem visualizing .json in the browsers (Opera, Mozzila, Chrome)
I have problem to visualize my scene in the browser.
I have blender4web and I'm doing this :
 1. exporting to json
 2. Open browser and put the link http://localhost:6687/apps_dev/folder/file.html
Then I get this:

Even turning off the firewall still same, I checked with others websites and they are working well.
I hope some one can help me please.

is ur internet working i mean other website working did u try

Is your server started ? https://www.blend4web.com/media/img_article/107/rect4179-1-4.jpg?v=

I'm voting to close this question as off-topic because it is about Blend4Web, not Blender.

Yes, internet its working well with others websites..   2) Thanks I'm checking the link right now.

Not sure if you'll be able to get any quality answers here, maybe you'll get a faster response over at Blend4Web Forum since its where most devs hang out.

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


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How to extrude a segment from a curve
I have added more segments to a Bezier curve, and when I try to extrude that segment, instead of having one line, I get 2 lines swirling. I need to have only one, how's this possible?

I think with curves, you're better off to select two adjacent points and extrude them together - you will probably still have to fix the handles somewhat, but you'll avoid the "dual loopty-loop" that comes with a single point extrusion.

When I extrude the 2 points, it causes a gap in between, was this the method you suggested, or did I understand incorrent? https://ibb.co/zx1Tqcy


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Procedural grunge & scratches node set up with Voronoi Node 2.93
Im following along a tutorial which was recorded in 2019, and the voronoi Node is different from the 2.93 Blender Im using. The result from the tutorial is significant different from what I'm getting. Can someone please see what my Node set up needs to get the same result at the tutorials?
https://www.youtube.com/watch?v=-KO_qkM93q8
The red section is the instructors, and the blue section is mine.
Here is my file provided:

@RoyalSkies did a followup video showing what changed in 2.8.1 that should get you back on track: https://www.youtube.com/watch?v=F2edriq1PAQ

I totally missed that, thanks for the link, life saver!


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How to align multiple vertices on face mesh
I want to align the vertices shown in the example for they form a rectangle. I tried selecting them all, and with S, Z, 0, they collapsed making a mess. So then I did each line individually ( S, Z, 0) so I can get the rectangle result. So is there a method which I can use to achieve this aligning them all at once?

You could use the shear tool, but I’m not sure how to get precise results in this case.

You may create a plane with subdivision and use shrinkwrap on the aimed object. Then merge them and remove colliding faces and connect vertices around that rectangle.


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How to model BMX spin back tuff shape
I'm trying to model this shape here which is a BMX tuff, I started off with circle and also 2nd attempt a cylinder. The result is not good. So I wanted to know what would be the best approach for this.

You can either give your topology more cuts to make subdiv work better or you can use Shift+E on certain edges to make it "sharper" but not too much

just give more segments to blades along with support loops.
also bevel the corner edges


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Spherical transparent node turns to Cube when colorRamp node is added
I have these nodes set up, and I get a foggy spherical shape which is grey colour. I wanted to change the colour and make it blue, but once I add the colorRamp, the sphere turns into a cube.
PS: I'm following this tutorial here: https://www.youtube.com/watch?v=TbrbF38_wUg&t=33s
at 15:04 is where the instructor sets up the node configuration.
Setting up a colour for the Atmospheric sphere is something I'd like to add.

You may have your color ramp going the wrong way, or there may be an alpha channel in the original gradient texture that you didn’t know about.

Gradient should be set to Density ...

I dont see Density in the Gradient settings.

Sorry for english,  ... Gradient's Color output should be connected to Density input of Volume Scatter node ... Just recheck tutorial node tree.


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How to add blend modes to emission shader node
Is there a way I can add a Blend mode node to connect to the emission node, and make the object beneath blend with the above object which has the emission.

Hi :). Do you mean the 'overlay, screen, hard light' blend modes in the MixRGB node?

Yes, I also uploaded a sample for better comprehension. If Possible I'd like to choose a blend mode which shows the details of the object below, like the one in PS: https://ibb.co/crpcSvc

Hey :). The blend modes are done using simple math (comparing existing pixel values). Eevee is physics based, so you need a physics based approach... something very different :))

OK, thanks for the info!


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How to make EQ wave length affect
I'm trying to animate a shape to imitate a EQ wave like in the video from 4:44 and beyond.
I have made a plane and divided it, and trying to animate the positions of the vertices, but there's no option for it. What method would be used for this type of animation to move the wave length up and down, right left as in the video.
https://www.youtube.com/watch?v=pjMCyLsRNig&ab_channel=InTheMix

you could use shape keys for that....should the move randomly or how...?

Bizualizer is an add-on that allows you to animate the spectrum from an actual audio file.  Ducky3D has a short YouTube tutorial on how to use it.

you can use this little node setup:

result:

animated:

I did a bit more research, and found an add-on called: Animate all, which give you the ability to animate the vertices/points. I found it easier than setting up the nodes.
https://ibb.co/QNvCgWp
https://www.youtube.com/watch?v=R8LbhcXDVWY


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Set pose bone rotation using world space direction (Python)
how would I go about doing this?
Say I have a Vector(0, 0, 1) pointing upwards in world space.
How would I align a child bone of some other bone so that it would be aligned along this vector, pointing up?
Seems like pose bone rotations are stored relative to parent pose bones, and I haven't figured a way to make this happen.
For starters I'd be happy to be able to simply make the bone point in right direction, and even better if I could somehow make bone keep its x-axis aligned towards the same direction as its parent bone's x-axis (the axis pointing right from bone's side).
I've done some scripting with rotations, edit and pose bones but my Matrix and Quaternion rotations understanding (and Blender API knowledge on this department too) is very limited.
Like this. Of course, the direction vector could be any directional vector.

I think it's best to do this in two steps. In the first step, we rotate the bone to align its y-axis with your custom vector. Then, in the second step, we rotate the bone along its y-axis (or the custom vector) to align its x-axis with its parent's x-axis. To do this, we'll need to project the parent's x-axis to the xz-plane of the bone. The following screenshots illustrate the two steps.

I decided to do this in the local space of the armature, so I needed to add an additional step to account for the armature object rotation. If the armature object is aligned with the world, the extra step can be skipped.
The script is attached below with comments explaining how I did it.
import bpy, mathutils

# Define the target vector
v = mathutils.Vector((0.0, 0.0, 1.0))

# Get the armature object by object name
arm = bpy.data.objects['Armature']
# Get the active bone. If you want to operator on a specific bone, use it's name instead. arm.pose.bones['Bone']
bone = arm.pose.bones[arm.data.bones.active.name]
# Get the components of the matrix of the bone. matrix is in the armature object space. matrix_basis is relative to the parent. decompose() returns the location, rotation, and scale from the matrix.
l, r, s = bone.matrix.decompose()

# The first step:
# rotation_difference returns a quaternion representing the rotation between two vectors. In our case, we need a quaternion that represent a rotation to our target vector.
r1 = bone.y_axis.rotation_difference(v)
# Apply the rotation to the bone's rotation
r.rotate(r1)

# The extra step:
# To cancel out the armature object rotation, we need to extract the rotation from its matrix_world and apply its inverse to the bone's rotation.
r_extra = arm.matrix_world.decompose()[1]
r.rotate(r_extra.inverted())

# The second step depends on our work so far being applied. We do that as follows.
# Update the matrix of the bone by building and assigning a new matrix from the old location and scale, and the modified rotation
bone.matrix = mathutils.Matrix.LocRotScale(l, r, s)
# Trigger an update.
bpy.context.view_layer.update()

# The second step:
# Repeating the first step with the parent's x-axis and the bone's x-axis will rotate the whole bone. This is not what we want. We want the bone to rotate about its y-axis. This means we need to use the parent's x-axis projection on the bone's xz-plane instead.
# I couldn't find a direct way to achieve this in the API, so I constructed the projection with the next best thing I could find.
parent_x = bone.parent.x_axis
x_proj = parent_x.project(bone.x_axis)
z_proj = parent_x.project(bone.z_axis)
parent_x_proj = x_proj + z_proj
# The remaining steps were explained previously
r2 = bone.x_axis.rotation_difference(parent_x_proj)
r.rotate(r2)
bone.matrix = mathutils.Matrix.LocRotScale(l, r, s)

Hey, thanks! I'll check this out when I have time! I already got something working last night, after testing various things and after banging my head on the wall for maybe 4 hours. I definitely want to compare my "solution" to this and see how this works. Anyway - what I did: Calculate upper arm dir, calculate forearm dir, then using cross product calculate sideways and bone up/roll directions. I then built a rotations using these vectors by filling an identity matrix with these vectors. Moved armature ain't problem but my solution doesn't work yet if armature object itself has been rotated.

Thanks again for the reply - just had time to test it a few times. It is a different approach that what I could get done, and there are several useful functions used that I have to learn to use. I still have to find more info on "rotation_difference" and another thing I tried to use (to_track_quat) - seems like there is very little info available. Overall I feel API descriptions are really just that, mostly lacking any helpful / insightful info for those who are not familiar with those specific features or concepts.

You're welcome! I am glad I was able to help.


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Weight Painting - mesh going purple
Just started experimenting with Weight Painting, and for some reason, if I've painted anything on a mesh and then right click on an armature, the mesh goes purple. What's happening here? How do you fix this? Also, is there any way of being able to select between meshes with right click if you have Select set to Left Click instead?
Thanks


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Weight Painting - using a single colour
How exactly can you use a single colour when using Weight Paints? I've added a few in custom colours in the User Preferences - blue, light blue, green, orange and red - but no matter what brush type I use, I keep getting a mixture of two colours, eg: orange mixed with green, with the green around the sides of the orange. Is there any way of just using one solid colour?
Thanks

I'm not sure of what you mean.
Weight painting needs at least two colors no matter what because it has to represent values between 0 and 1. So you will always have at least one color for 0, one color for 1 and it will display in between colors for every value between.
If you want to have only two colors for your weights paint (ie black and white), just set only two colors in your userprefs:

If you want to have as little transition as possible between values, use the "constant" interpolation and decay one of the sliders:


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Weight painting not working
I'm currently practising with weight painting and I have my armature named - right_arm.L and right_arm.R etc. and I have X-Mirror enabled in the Options, but my Weight Painting on one side isn't showing up on the other. Any suggestions?

Thanks

I just tested it out and it worked as soon as I enabled the X-mirror option. Not sure where is the issue there.

Weird. Don't get that. o_O

Went back and tested it some more and even reverted back to Factory Settings, but it just won't work for me. Guess all I can do is delete the left side, work on the right and then re-duplicate them.


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Repeating walk cycle
I seem to be having problems repeating a walk cycle. The book I'm reading says to adjust the scale and set it to repeat 5-6 times. The walk cycle itself is about 40 frames. Though I've scaled it to make it longer and it repeats, the cycle only lasts 40 frames and then resets. It doesn't reach the end of the bar, which is scaled to 120 in the NLA Editor. Is this supposed to happen? Or is it supposed to reach the far end?
Thanks

Can anyone help?


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Copy Pose and Copy Inverted Pose Buttons
I'm following a Blender book on character creation. It mentions about clicking on Copy Pose and Paste Inverted Pose buttons on the header. I'm guessing it's referring to on the Dope Sheet, which I have open in a separate partition. Either way, I'm not seeing those buttons anywhere and the buttons I thought were them don't do the job properly, but copy/paste the keyframes to the copy/paste buffer.
Do these buttons exist? If so, where are they?
Thanks.

Please always search the documentation first.

See, I thought those were the buttons, but whenever I click on the Paste Inverted Pose button, the model poses weirdly. However, if I use Shift, Ctrl + Z, it poses correctly.

It would help if you included your research in the question and document how "the model poses weirdly". (It's not supposed to pose weirdly.)