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Can't see parts of a wall when viewed through a glass panel (shower cabin) from a top view angle
I would like to ask for help with an issue I'm having regarding the reflections / refraction of a glass material for Cycles (Blender 4.0.2).
The glass material is assigned to 2 shower cabin glass panels that are 8mm thick. The issue I'm having is that when viewed from a top view angle (perspective camera not orthographic), the glass panels show the reflections of the environment but parts of the walls behind the glass panels are not visible.
In order to fix this, do I simply need to change the IOR value or do I have to add more shaders / mix shaders to the glass material?
Thanks in advance for any tips!
An example of what I mean can be seen in the image below:

This is what the current glass material shader looks like:

This is what the glass material looks like when viewed from a different angle:

If you mean the front glass which reflects the bright wall and the grey floor: well, that's normal for real glass, at low angles reflectivity can get very high so that the glass seems almost opaque.
Here is a real world example, unfortunately I had no glass at hand, only a plastic CD cover - but to show the principle it is good enough:

As you can see, when taking a pictures almost perpendicular to the cover, you can see the floor behind it. When I tilt the cover so that the viewing angle becomes lower and the bright window with the blinds is reflected, the floor is mostly invisible.
Another thing you can see is that it not only depends on the angle, but also on the brightness of what is reflected and what is transmitted through the glass.
The floor is quite dark, the window is very bright. But even in the left picture, the reflection of my dark phone is more transparent then the part of my hand which is lit up, even though angle is almost the same between those areas.
So there are three main factors: the viewing angle, the brightness of the reflection (bright reflection more opaque, darker reflection more transparent) and the brightness of the background (brighter background better visible, darker background less visible).
Now for an example in Blender: to the left is a wall with a bright pattern, to the right a wall with a dark pattern. Next to them on both sides are glass panes which the camera views both under a low angle. With a dark pattern on the background wall, both reflections are very good visible, the bright one almost completely hiding the background behind the glass:

If I now change the background to a bright pattern, it becomes much better visible through the glass, with the dark reflection becoming hardly visible and the pattern even being visible through the bright reflection:

Long story short: if you want to make a realistic render (and the scene looks like it is supposed to be realistic), I would actually keep it like it is.
But if you want to reduce the reflectivity, decreasing the IOR value will not have much of an effect, since the reflectivity will always be quite visible there unless the IOR is 1, and then the glass is simply invisible, transmission with IOR 1 is basically alpha transparent.
The only thing you could do is use the Fresnel or Facing output of a Layer Weight node, plug it into a Color Ramp to invert it and then plug it into the Alpha input of the Principled BSDF and play with the values until you like the result. However, in my opinion this will not look like real glass:

I've been experimenting with different approaches to the glass shader. Thank you, Gordon Brinkmann, for your detailed reply; inspired by your tip to use Fresnel as an input, I created this setup:

Mixing the Principled BSDF with a Refraction BSDF shader based on Fresnel resulted in this:

This seemed to improve the visibility of the tiles behind the glass panel. However, the reflections of the brighter tiles were still too visible, so I adjusted the shader again to this:

Now I'm using the Is Diffuse Ray from the Light Path node combined with an Add math node to determine how much of the diffuse color of objects behind the glass panels is visible, resulting in this slight difference:

Of course, this completely breaks realism, and when viewed from nearly perpendicular angles, the Refraction BSDF starts causing issues, like this weird black circle on the glass:

But if the image is never rendered from this angle, it should be alright. I thought I'd share this, as it might be useful to you or someone else.

Glad I could help and you found some solution. I actually only use a Principled BSDF or Glass BSDF 99% of the times I need a glass material. No mixing by light paths or anything else. And an additional Principled Volume for coloring sometimes.


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Why are the following manual instructions not working (render/freestyle/export_svg)?
Just installed blender and need to generate an SVG file, but am not seeing the add-on that the instructions mention.

Thanx, Alan

What version of Blender are you using ? The Freestyle exporter is bundled starting from version 2.72.1. Also you can Shift + click on both Official and Communuity checkmarks so to search in both categories simultaneously.

Splashcreen says 2.72b

This add-on is under the community tab in your user preferences>add-ons.
 Search for freestyle and it will come up

I just did exactly what you showed and got nothing. I am using linux, if that makes a difference.

How do I show a screenshot here?

In comments pictures are disabled, but you can edit your question(this is encouraged when adding new information), there is an icon to add a picture, just drag and drop the file.

Added a screenshot to the original message and was going to add another with a search for "fr" which did generate a result, but was not allowed to.

source: Stack Exchange

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

sort: votes


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Sound export in 44100 Hz instead of 48000 Hz, why?
I started to use Blender as a solution for video editing, very powerful and agreeable. Nevertheless, I have a bug that I can't resolve. The sound of my  video is in 48kHz, my users preferences are also in 48kHz, but when I export in H264 the final editing, the sound goes out in 44kHz.
I also exported the sound only in wav, and same issue. Any idea where this issue comes from?

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


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How to make 360° renders for Virtual Reality devices (ie Oculus, etc) using Blender?
I'm trying to figure out how to make 360-degree panoramic renders for virtual reality content? I'm trying to make the content to the specs of HoneyVR to submit something to their VR program but they are asking for the content in "equirectangular project" at 2:1 aspect ratio and I'm a bit loss.
I'm using Blender / Cycles but I can use other renderers too.  Any help or tutorials much appreciated!
Here is the link to the HoneyVR file specifications which shows the needed aspect ratios, resolutions, etc.  Is it possible with Blender?
http://www.honeyvr.com/content-specs/

With Cycles you can set your Camera to Panoramic and Equirectangular

Make sure you have recent Blender builds. Also see the Blender manual docs for Camera

Why does the preview tile at the top and bottom? That's misleading

@Random832 what's misleading about it?

Those edges aren't normally supposed to match up. They seem to, by coincidence, in your image, but normally e.g. one is the floor and the other's the ceiling. Tiling them in the preview could lead someone to believe that there's something wrong with the render when they don't match.

Hey thanks for the info Random832. Does anybody know if you can render the panos with Blender and V-ray or do you have to use Cycles?

They also accept 3D-360° renders. For those you need a build from the spherical-stereo branch. I keep them updated in my site, until we have it officially in Blender: [ link ]


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How to make an area transparent?
I want to make the black portion in my model transparent so that inside face can be slightly visible. How can i do this?

In CYCLES select the mesh you want to be transparent. Go to the Object header and check the Transparency box.

Go to the Material header, add a new material and decrease the Alpha value in the Settings panel as pictured below.

You may also change the color of transparency.

In BLENDER INTERNAL do the same things in Object header as shown above. Next go to the Material header, check the Transparency box and decrease the Alpha value in Transparency panel.

If your model is one solid mesh (does not consist of many loose meshes) you may add a transparent material to any part of it (any faces) you like.
Create the transparent material (using methods I've shown above) and assign it to the desired faces.

Here's the result.

With very little information provided, I think you simply need to drop the Alpha on the black Material. If you want complete transparency, and those faces aren't essential, you could just delete them.


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How do you switch to a completely different camera in a different Blender layer?
Say I create another scene in a blank layer. How do I switch to that totally different scene during rendering?
Thanks guys!

See http://blender.stackexchange.com/q/1067/599. Though instead of animating the visibility of all the objects on separate layers (you could do in it a few clicks, but it still is a bit clunky), you might want to try using separate scenes (or even separate files, with linked objects where necessary) and rendering the two scenes out separately, combining them later in the compositor.

What do you mean animating the visibility of all the objects on separate layers?  WHy is that clunky?  Does it work?  Perhaps you are right no matter what though in the sense that I should use difference files!

It would work, but instead of animating one property (the visibility of a layer (not supported), or the visibility of a scene strip in the VSE) you would have to animate the visibility per-object. There is a way to do it in a few clicks, the way i'm thinking of will interfere with other animations.


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How to acces all objects via Python in the Game Engine?
I have different objects in a scene and I want to control them with python code. My question is? Do I have to create a script for every object or I can control all of them with only one python script? I've tried with only one script but then there is only one object as the controller... and I need to change the properties of an object that is not the "controller". I don't know if I explained this well.

You can access all objects from the scene by its name:
import GameLogic
scene = GameLogic.getCurrentScene()
obj=scene.objects['ObjectName']

To access the vertices:
import GameLogic

scene = GameLogic.getCurrentScene()
obj=scene.objects['Cube']

mesh = obj.meshes[0]

for v in range(mesh.getVertexArrayLength(0)):
    vert = mesh.getVertex(0, v)
    print( "%d,%d,%d" % ( vert.x, vert.y, vert.z ))

print( dir( vert ))

Thanks! but I need to access to the vertex of the object and using scene = GameLogic.getCurrentScene() I can't do getVertex because is not defined

You should call print( dir ( obj )) to see what is available. Added access to vertices to the answer.


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Need help with riggify
I’m new to blender and I’m having trouble with riggify. Every time I click deform with automatic weights it causes my character to expand. Can someone tell me what I’m doing wrong?

Hello and welcome. Please use a title that matches the content of the post. It should read like a question, be descriptive but succinct, unique and identifying, summarizing the problem so that anyone searching for similar issues is likely to find this. Remove anything superfluous, avoid using words like "this", "help with", "issue" or "question about", instead describe what "it" is. Remember, your title is the first thing visitors see, answers you get depend heavily on it. See What is the problem of asking “How do I do this?"

Where did your model come from and did you apply the rotation and scale (Ctrl-A > Rotation & Scale) to it and the Scale to the armature before doing the parenting?

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


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Remesh Text FPS Low (0.16)
I'm trying to animate a text with a wave modifier so I have to remesh the text for the animation to work properly. But everytime I try to play the animation my FPS go to 0.16 or less. If I try to hide the text or modify it, Blender also crashes and i have a Not responging notification. Does someone know how to fix it? Thanks

Hello and welcome. It’s important to understand the limitations of your setup before setting your voxel size too low (currently at 1mm). Doing so can generate a massive amount of geometry, which may significantly slow down or even crash the software.

Apart from what everybody already said about how unnecessary dense your mesh is, in my answer here I'm saying something about low FPS playback: https://blender.stackexchange.com/questions/323781/blender-grease-pencil-file-more-than-1gb-causes-frame-drops-to-5-fps-during-pla/323785#323785

This is because your Remesh modifier resolution is set to one millimeter. That’s absurdly high, generating more geometry than your computer can handle effectively.

I just did an imitation scene with the statistics overlays on. It's about 20 to 30 million triangles, depending on the scale approximation. The mesh is so dense you need to zoom in to macro level to even distinguish it, otherwise it's either all black or a nice demonstration of moiré effect. https://i.imgur.com/ixghXlS.png

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


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Limitations on .stl file importing
I have .stl data files that I'm trying to import into Blender. Large, over 100MB. I'm having trouble importing them, and I'm wondering if the size might be the reason. They all return the following error lines upon attempting import:
Traceback (most recent call last):
  File "C:\...\AppData\Roaming\Blender Foundation\Blender\2.57\scripts\addons\io_mesh_stl\__init__.py", line 86, in execute
    paths = [os.path.join(self.directory, name.name) for name in self.files]
  File "C:\...\AppData\Roaming\Blender Foundation\Blender\2.57\scripts\addons\io_mesh_stl\__init__.py", line 86, in <listcomp>
    paths = [os.path.join(self.directory, name.name) for name in self.files]
  File "C:\...\AppData\Roaming\Blender Foundation\Blender\2.57\scripts\modules\bpy_types.py", line 626, in __getattribute__
    return getattr(properties, attr)
UnicodeDecodeError: 'utf8' codec can't decode byte 0xee in position 27: invalid continuation byte

location:<unknown location>:-1

This looks like a bug report, can you give a link to a file that fails to import?

@ideasman42 the files aren't public

@JNF it looks too much like a bug and without the files, we will just be here speculating. Voted to close.

@iKlsR, agreeing. Something with version 2.57 that worked out when I upgraded

It sounds like your having some sort of corruption with your binary (source). Change the settings of your import or reexporting the model should fix it.

Can't reexport - it's data received from elsewhere. Sounds funny all files are corrupted. Can there maybe be differences in the .stl standard itself?

@JNF scratch that. I'm guessing its an import then. The wikipedia page says that there are two types of STL files. ASCII and binary. I'm guessing there's an option to import binary?

Good point. Can't find such an option on the interface (blender 2.57). I'd be glad to check if that can solve the issue. Tell me if you find it...

Here's the troubleshoot/bug page: http://projects.blender.org/tracker/?func=detail&atid=469&aid=22837&group_id=153

I see someone addressing the issue there. But I'm not sure how to use his code

Ok, it looks like he patched it. If you get a development build, it might be fixed. You can download a build from: http://builder.blender.org/download

Updated to latest version. It presumably does the import. I end up with a blank viewport


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What do the settings in the new Principled Shader actually do?
I'm trying to understand how the new Principled Shader in 2.79 works, so I can make a video tutorial on it.
I get most of it, but a few things have me confused, and there currently isn't much documentation for it.

Since most dielectric materials have an IOR of 1.45, is the default 0.5 value for Specular the correct value?
What does "Sheen" actually do? I've read that it provides an "additional grazing" component useful for fabric. But what does it actually do? Is it adding an additional white fresnel component for the color channel?
Why is Sheen Tint 0.5 by default? Just looks odd since most values are 0, yet this is 0.5. Just curious since it doesn't do anything until Sheen is turned on anyway.
Why does it use Roughness for the specularity, but Gloss for the Clearcoat? Their only difference is that they are opposites of each other, so it requires extra mental effort to think before changing it. Is there a reason for this that I'm missing?
What are some practical situations where you would want a different clearcoat normal? I can only think of situations where you'd want a smooth clearcoat, like metallic paint or carbon fiber. Is there any other reason for wanting bump on a clearcoat?

This may be useful if you haven't seen it.

There already is a good tutorial: https://www.youtube.com/watch?v=jcLwBy3eBh0

Does the person who answers get credit in your video tutorial?  :)

haha sure thing X-27 :)

Most of these answers can be dug out of the paper linked by timaroberts

The default specular of 0.5 corresponds to an IOR of 1.5. See section 5.4 of the paper:

In place of an explicit index-of-refraction, or ior, our specular parameter determines the incident
  specular amount. The normalized range of this parameter is remapped linearly to the incident specular
  range [0.0, 0.08]. This corresponds to ior values in the range [1.0, 1.8], encompassing most common
  materials. Notably, the middle of the parameter range corresponds to an ior of 1.5, a very typical
  value, and is also our default. The specular parameter may be pushed beyond one to reach higher ior
  values but should be done with caution. This mapping of the parameter has helped greatly in getting artists to make plausible materials given that real-world incident reflectance values are so unintuitively
  low.

(cont) Note that this is different from PBR spec/gloss shaders, which directly map the incident specular (the 0.0 - 0.08) values mentioned in the above paragraph. "Specular" outputs from software such as Substance should NOT be connected to this input, they contain different data entirely. Cycles' fresnel node uses a default IOR of 1.45 instead of 1.5, so it will have a slightly different look by default. Both 1.45 and 1.5 were chosen for being nice round numbers in the rough ballpark of most dielectrics, so neither is necessarily right or wrong as the default. Worth noting the viewport shader in Substance does not allow editing of this setting and just locks it off at 0.5, so if you want to match Substance, you should not modify this value.
See section 4.5 of the Disney paper. It pushes up the specular component at grazing angles to approximate light interacting with cloth fibers. It adds some extra off-angle sheen similar to Cycles' velvet shader
Since the light diffusing through cloth will pick up the color of the cloth, there's an option, sheen tint, to tint the extra spec with the base color. Since this is useful in many cases, it defaults to 0.5 so it is auto-enabled when sheen is enabled.
To be honest, I have no idea why this was done. Some other PBR shaders, such as Arnold's aiStandardSurface, still use roughness for clearcoat. Likely it made sense to someone at Disney working on the shader and they just ran with it. They didn't bother to record their reasoning in the original paper that I can find.
The paper mentions they used clearcoat normals to get some floor sparkle effects in Wreck It Ralph. Also, since the clearcoat normal is independent (to allow things like carbon fiber as you mentioned), you still need some ability to set it when you DO want your base normals to also apply to the clearcoat. In this case you aren't really applying a different normal, you'd just connect the same bump/normal node to both inputs, but you need the separate input so you have the option to NOT apply the bump/normal map to the clearcoat.

Thanks! That's extremely helpful.
"this is different from PBR spec/gloss shaders, which directly map the incident specular (the 0.0 - 0.08) values mentioned in the above paragraph." By this, do you mean a typical specular workflow, where a spec map is used to show which parts of the material are reflective/non-reflective?
On a related note, where should a reflection map be used in the Principled Shader? Or is it just not applicable to the Metalness workflow?

The PBR "specular" map is different from classic diffuse/specular. Classic spec map just defines reflection intensity. A PBR-style spec map defines IOR itself for each color channel. Reflection maps are not used with the metallic workflow, although sometimes it might be useful to stick them on the clearcoat or specular channel if you need some extra, non-physical control.

To complement J's comment above somewhat, have a look at Mike Pan's car paint brdf http://blog.mikepan.com/post/137759885931/realistic-car-paint-brdf-material. Even more specifically, in the real world, look at the area under your car door handle and see what your nails do to the clearcoat.

1 to 3 seem to be covered everyone else's answers but after reading through them, I maybe be able to provide an answer based on logic reasoning for questions 4 and 5
So background I have a degree in product design and development and finishings is something that I did a bit of works on. Seeing as we are talking about a physically based  shader then it's only fair we look at it from real world point of view instead of just cgi (Which btw I'm still getting used to the terms and what they do so bear  with me)

Roughness for specularity makes sense because what ever is under the clearcoat will have varying dialectic properties where as clear coat is almost like metal it's 100%  gloss  in the real world clearcoat would be something like lacquer or varnish  only time it wouldn't be 100% gloss is if it's got surface inperfections or it wasnt applied properly in the first place again surface in perfections.
Think of it as a varnished table the clear coat would be noticeable as it will give the table better glossy look then an unvarnished table which will have the diffuse as well as a bit of its own gloss.
A different clearcoat normal would work great with your surface imperfections such as a scratch in the clearcoat layer  e.g. scratched lacquer on a car or scuffed varnish on a table   it would have a noticeable bump but not nessacerly one that effects the material under it    ...in real world terms hopefully it will work in cgi

I'm going to go away and try a few experiments with this and will send them to you via Twitter or Facebook

Try to update your answer here please if possible as well, that way your research can help others in the future.


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I like to close a Mesh in Blender to the floor, see attached Photos
i have some photogrammetry meshes from Drones.
(from poly.cam, so *.obj, *.dae end even Pointcloud like *.ply is possible as initial file)
I like to close all open sides to the floor.
See Photos for better understanding:

is there a solution in Blender to do this?
thanks
Flo


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How to copy an object(s) from a large Blender instance to different location in another instance
I have a large scene in a instance/file. I want to copy a few objects from that instance to a new instance but at at a completely different location. When I paste it, perhaps unsurprisingly it is at the same x,y,z coordinates of original source scene.
How can I paste to a specific location? I have tried to use Global Transform Copy but without success, either I am doing it wrong or the two instances dont share the same clipboard which I guess is likely.
I would like to retain the relative positions of the copied objects when as a group they are pasted into the target instance.
Thanks in advance
Larry

Use the "append" command in the "file" menu

Thanks, Daniel, thats a good way to add items to my new instance I wasn't aware of but it works like cut and paste did in the method I've been using. What I need is a method to choose its new location.

A suggestion:

In the original file, add an "empty" object.
Parent every single object to that empty object (ctrl+p -> keep transform)
Import that empty object into the new file
If you want, unparent the items from the "empty" object (alt+p -> keep transform)


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how do i straighten these mesh edges?
I am currently starting a personal modeling project and I've noticed that my current mesh for the handle could be a bit neater for in the future when i do the UV handling work. Is there any techniques i can use to make it look nicer?

The shape of the handle is not straight, so why and in which way do you want to straighten the edges?


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Image Texture Via Spotlight Not Reflecting Onto Wall
Working on a project irl that requires splitting projector imaging via mirrors. I am testing features in Blender and I can't get my spotlight using an image texture to reflect off of the mirror surface I created and "project" onto the wall. The plane is reflecting as we see the floor seam in camera view, but the image from the spotlight is not presented onto the wall, just white light.
First, is it even possible to get this to work in Blender? If so, what could I change to get it to work right?
Find relevant (and possibly irrelevant) settings below:
Working in Supported GPU Cycles
Render Properties:
32 Total Bounces, 24 Glossy; 10.00 Indirect Light Clamping; Reflective Caustics is on
Spotlight:
Color FFFFFFFF; 1000 W; Multiple Importance is on; Ray Visibilities are all on; Shader Nodes are below

Mirror Plane:
Standard plane with glossy BSDF shader; Metallic 1.000; Roughness 0.000; IOR 1.5
I also scaled everything before render


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Wood grain direction
Very new to Blender and need some help with wood grain and exporting some files.
I have around 35 sample doors that I need a wood texture for that needs to be exported in glb/gltf format for a specific WordPress website plugin, Visody, that my employer is using (Mainly it's free and has the most features).
The doors are modeled in Fusion 360 and have exported them as FBX files so I don't need to select every single polygon to apply the material as there are 35+ doors and this would take forever.
(If there's a better way please let me know)
I am running into a problem where the direction of grain is changing whether or not the surface is curved or a separate surface.
In the example image I need the grain in the yellow section to be vertical but depending on the surface some are horizontal.
Any help is appreciated, Thanks!

You need to UV unwrap your and align all the faces to aim in the direction you want the grain to go. Probably would work ok if you just selected all of one "side" of the door (meaning inside or outside) in Edit Mode and press U > Unwrap to unwrap it all as one island. Then just rotate that to align with the grain of your wood texture. Then do the same to the other side or mirror it, whatever works for your needs.

I will give it a shot, thank you for your help


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How to use absolute value in Loopcut and edge slide?
I want to make for example edge slide by 0.5 unit. How can I achieve this ? I don't want to use in edge slide fraction (from -1 to 1), instead real slide value.
I found that in previous versions of Blender there was in Edge Loop Proportional option, but I can't find it in newest Blender :/
http://wiki.blender.org/index.php/Dev:Ref/Outdated/Release_Notes/Modeling/Meshes/Advanced_Tools
From old manual:
Pressing P while positioning the loop cut will enter non-proportional mode, which keeps the shape of one end of the faceloop regardless of where the cut is positioned. Pressing F while in non-proportional mode flips which side of the faceloop is used to determine the shape of the cut.

Maya have this, Absolute Value.
http://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/Maya/files/Edit-Mesh--Slide-Edge-Tool-htm.html

Please place 1 or more images in the question to help others to understand your question.

I don't think it is possible in blender.

Isn't proportional now called even mode? E to enable it. If it doesn't behave like in maya it should be relatively straight forward to write a script.

My understanding of even is that each vertex is the same distance from one of the adjoining edge loops.  It is not 100% clear to me why slide is necessary here, though the initial placement of loop cut may be a problem.  In the image above one cannot see the edge loops to see the possible effects.  A more contained image would be better.  The lines are cut off on the view window.

When you press Ctrl + R you actually perform two actions: Loop Cut + Edge Slide.
The easiest way to slide edges a certain distance from a vertex is to slide to a vertex first, then slide the desired distance.

Ctrl + R + LMB to select the ring to cut
1 (or -1) to place the loop at the very last vertex of the edge you are cutting
Ctrl + E + Edge Slide + relative distance

NOTE
In this way you can set zero at a vertex instead at the center.
It helps to calculate the absolute distance (as Carlo suggests), but actually doesn't allow to set edge slide by unit.
You don't need to calculate the value manually: use Python expressions instead, simply typing = followed by the operation
Check Edge Info: Length in Property Panel (N)

Even off
If you're sliding proportionally (Even off), you have to choose the edge wich the absolute slide amount refers to.
In this example, I want the edge to slide 0.5 units along the shortest edge.

Now the tricky part: type this simple operation (thanks @Carlo):
= absolute_distance / edge_lenght

in my case:
= 0.5 / 1.13

Even on
From Blender Manual

Even E
Forces the edge loop to match the shape of the adjacent edge loop. You can flip to the opposite vertex using F. Use Alt-Wheel to change the control edge.
Flip F
When Even mode is active, this flips between the two adjacent edge loops the active edge loop will match

In this case, the operation is a bit longer, because zero is at the median point of the edge :
  = absolute_distance / edge_lenght - edge_lenght / 2

in my case:
= 0.5 / 1.13 - 1.13 / 2

note:
You'll notice a rounding error (the value is not exactly 0.5), because some approximation

Edge slide takes only a Factor (-1 to 1) as imput, not a "absolute distance". While this method make math operation easier (Factor=Absolute Distance/Edge lenght), I don't think that the problem can be marked as solved.

@Carlo you're right! Since the edges can have different lenghts, Blender use Percentage values to proportionally slide despite the different lenghts. To make math operations, one ought to indicate an edge as reference.

In the above image a loop cut was made ... moved to one extreme side ... then a simple grab was performed in the global X .5 direction.  Length is enabled to show the edge in question.
If the loop is lined up with the global XYZ axis you can type
Keyboard GX1 ... Grab Move in the X axis 1 unit.
If the loop should be moved in the local coordinate axis you can type
Keyboard GXX1 ... Grab Move in the local X axis 1 unit
Loops were created at a relative zero location and moved by G [Grab] only.
You can consider creating an orientation as well.

Using the orientation based on a face orientation Y .75 units
Local axis still aligned with global axis.
GYY .75


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How to force creases into a cloth object?
I want to be able to simulate a cloth object where some of the edges want to crease to some angle. For example, this mesh below has a line of edges marked seam on the left, and on the right I've used edge crease to highly another line of edges.

And I want to be able to tell Blender that the seam marked edges should be bent to 90 degrees, and the creased edges to be bent to -90 degrees, which the following picture illustrates.
Thanks!

I tried to do this once years ago using a sort of genetic algorithm sort of approach, and shape keys, with mixed results, then last night a friend suggested I try cloth simulation, which seems much more promising.
I don't care if the solution has anything to do with seams or creasing, just so long as I can have Blender know it should bend part of a cloth object to some angle.
Edit: I want the physics simulator to do the bending for me, so for example, I would make the original flat mesh, and add something so it would know the edges should be creased to some angle, and then the simulator itself would do the bending for me along the edges as I've defined, to the pre-defined angle.
A Second Edit: What I'm trying to simulate is the way paper folds, as in this video here: https://www.youtube.com/watch?v=2Q-A38tK4SA
The video depicts the result of folding concentric squares into a square piece of paper, which causes it to turn into a saddle, or potato chip shape. I can rig up bones to bend the "paper" model in Blender, but I want Blender to actually do the saddle-shape deformation, based on the fact that the model is creasing.
This is a rigged plane:

And notice it doesn't reproduce the saddle shape. I think it would be area preserving that would mimic paper, since paper can't stretch or shrink, but I don't think volume preservation will work right.

You should probably use pinning for this. If I understand correctly what you want vertex groups will allow you to define parts of the mesh not altered by the cloth simulation.
Select a few corner vertex, as many as you need, the more selected vertex the stiffer the animation will be, and assign them to a new Vertex Group.

Use that vertex group for pinning under the Physics > Cloth > Pinning.
You can use this in conjunction with shape keys and animation to drive the shape from flat to folder or similar.

It's not quite what I'm trying to do—I don't want to pin things in place, I want the cloth simulation to add the creases. So I would start with the flat model, and the physics simulator would do the creasing part for me (after I define somehow what edges should be creased and to what angle). Thank you for the suggestion though.

Maybe instead of cloth I should be looking at the soft body physics

Re-read the last part of my answer specifically the "You can use this in conjunction with shape keys and animation to drive the shape from flat to folder or similar." Just animate the position of the vertex

Yeah, I don't want to animate the position of the vertex, I want the physics simulator to do it, so that they obey certain constraints.

Well you can animate any other object like a thin rod set to rigid body to form up those creases using physics, but I fear the result will be practically the same


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Is it possible to group sculpting brushes to adjust settings for selected brushes only?
This is my goal:
I want to group certain brushes to share a brush size setting. I imagine it like in Nomad Sculpt, for those who are familiar. Brushes that are used for broad strokes like draw or clay strips share a brush size, while others like smooth and flatten share another, and things like grab and elastic deform another again.
This is super useful as I rarely need the same size for ALL brushes, but I also don't need individual sizes for each brush. Having assignable brush groups that share certain settings would be extremely useful. Ideally you'd have control over which settings are shared and which aren't.
I am sure there must exist an addon that adds this functionality, but I can't seem to find it. Anybody got any pointers for me? Thank you!


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Display editable material values in property view
First off: I'm sorry if this has been asked before, it most definitely has, but after an hour of searching and experimenting I have to accept I seem to lack the jargon to properly search for it...
That out of the way, I want to "reveal" specific material values in the property view (Shift F7), similar to making a variable public in Unity.
An example: I want to be able to adjust the scale of a Mapping node without having to open the material view.
I am almost certain that this is probably done via custom properties, but I couldn't find out how. Any advice on how it's done or where to find an answer?

You can bring a custom property into a material shader with the Attribute node by using its name in there (case-sensitive, so make sure to spell them exactly the same) or by using the property as a driver.

It sounds as if you may be asking how to use Blender's Custom Properties?

After a bit more trial and error Gordon Brinkmann's explanation worked. I got attribute nodes to work. Here is what I found out:

as Gordon said, spelling is really important

Just as important is setting the correct min, max and default values, i.e. for moving the textures left or right you would obviously have to assign a negative min value

For rotation the best way is to use pi as max value and negative pi for min value

What didn't work was adding custom properties to the material property view. I had to add custom properties to the object itself. That meant setting the attribute node type to "Object".

But that also meant I had to add these properties to ALL objects. The addon Copy Attributes Menu proved invaluable

Make sure to set all the default values before copying to save a lot of work

I hope this helped anyone who also struggled with this admittedly simple function. One day I will tackle drivers, but I was able to do everything with the Attribute node, even if it wasn't the most efficient way.


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Unable to export baked shape keys with animation as .fbx blender 4.0 and 4.2.1
I am attempting to export a .fbx file from blender to unreal that includes a character and their animations.
The problem:
upon export and reimport to blender or unreal the mesh, rig, morph targets/shape keys, and animation, all import successfully. The problem is the shape keys animation is lost. I have tried numerous methods of baking the shape keys before exporting but the baked shape key action is always lost on export.
What I've tried:
over the last week I have tried every tutorial and forum solution I could find including:
blenders built in object/animation/bake action
bake shape keys add on
bake drivers add on
every combination of animation bake on .fbx export including disabling bake animation
What I've learned:
I can copy paste the character, rig, and animation layers to a new project and they still work
I can delete the rig and shape key drivers after baking, and they still work
I can see the baked shape keyframes in the dope sheet/shape key editor and graph editor and NLA strip before pushing down
whenever I reimport, the shape keyframes all disappear completely.
The export setting Force start/end keying forces the action/NLA layer to remain upon import, but all the frames are still lost other than the added start and end frames.

Shape keys will not export if the export settings modify your mesh in any way. In my case, I had the Triangulate Mesh option enabled during export because I work with quads and needed the mesh triangulated for import into a game engine. I unchecked the Triangulate option and instead triangulated the mesh in Blender manually using Edit Mode > Ctrl+T before exporting. That solved the problem.


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Using python to manipulate vertices
I would like to perform the following things:

for the selected object get all the vertices, treat the vertices as a vector, perform a Matrix x Vector multiplication
do the same Matrix x Vector multiplication for all the objects on a scene

The purpose of this is to visualize the result of a given operation using concepts from linear algebra, but also have a quick way to manipulate the source (the 3D mesh).
So far I don't understand the reasoning behind the naming and the general design of the python API under Blender. Multiple things access the same information which is not always related to the name of the access methods used.
Sometimes the autocomplete feature CTRLSPACE gets in the way, for example
bpy.context.selected_objects[0]

with CTRLSPACE becomes
bpy.context.selected_objects[0]['cycles'].name

which doesn't seem to be a useful piece of information when there is no object named cycles.  Instead what I want is something like
bpy.context.selected_objects[0].name

Can show me how to perform these tasks simply?

You can do this by iterating through all of the objects in the scene which are found at bpy.data.objects. This is all the objects in all the all the scenes. You could also use bpy.contex.scene.objects which would be the objects in the current scene. Then you would want to make sure it was a mesh object by checking its type. Then get all the vertex positions, convert them to world space, and make them tuples, if you want. In the end you get this:
import bpy
for object in bpy.data.objects:
    if object.type == "MESH": #check if mesh object
        verts = [object.matrix_world * vert.co for vert in object.data.vertices] #get vertex data
        tup_verts = [vert.to_tuple() for vert in verts] #convert to tuples
        print(tup_verts) #display list

You could add tup_verts to a larger list if you wanted, and you can leave the positions as Vectors by accessing verts instead of tup_verts
In more recent versions of blender (>=2.80) it is necessary to use the "@" operator for the element-wise matrix multiplication instead of "*". I.e. "object.matrix_world @ vert.co". See this answer: https://blender.stackexchange.com/a/129474/22220

interesting, I need to experiment with this, but if just want the local object, without translations, scalings and rotations I'll just skip the vert.co * object.matrix_world part ?

yep @user2485710, just do verts = [vert.co for vert in object.data.vertices].


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Object not visible in render
I have a model which you can see here (camera perspective).

In the second image, you can see how the render turned out.

I'm at my wit's end trying to figure our why it's not showing up in the render. If anyone needs more information, just ask and I'll get it to you. I've already checked the normals and they're not the cause.

related: http://blender.stackexchange.com/questions/33787/why-is-part-of-my-model-not-being-rendered  (while this link was created later, the answer is more universally useful)

Another reason can be keyframes. You move an object to place it in front of the camera, hit render... And it doesn't render because you didn't key the location in front of the camera

I don't have the reputation to answer this question, but if your object has any particles / hair you may have "Show emitter" disabled in the ParticleSettings

@IanHunter I had the same issue and your suggestion solved my issue! Thanks!

In object mode press W -> clear all restricted render. That will make all objects visible in the render. Also you can select and object and hit Ctrl+Alt+H to unrestrict render on the selected object. If there are objects that you have that you do not want rendered you can click the camera button next to the objects name in the outliner which is usually the top right window. This toggles camera visibility.
Version 2.80+ : Press F3 to bring in the search operator  and type clear all restrict render.

Thanks. This fixes it. I must have bumped something there.

I've actually done that several times myself. Probably from hitting W in object mode and immediately clicking while the object is selected.

I have found that problem a strange amount of times. Each time I am pretty sure I never pressed W. Can you revert it pressing W, because each time that happens I have to go down the object outliner and toggle venera

Oops. I wish I could edit that comment because I accidentally pressed 'post.' As I as saying: ... and toggle RENDERABLE (that auto correct) for each individual object.

I tried all the answers in this thread, but in v2.91, it seems that the option is now called Clear render region. All my objects was selected as "To be rendered" into the object explorer tree, but I noticed the object that wasn't displayed was a duplicate. So in the object that is not rendered, go to object properties, and check under Instancing that the Render checkbox is ticked.

Also check duplication setting of the object. I copied a part of existing mesh and separated the copied part to a new mesh. After doing this, Duplication setting for this new object was set to "Group". I changed it to "None" and the object finally appeared in rendered view.

I wasted an entire morning trying to figure that one out. If anyone knows what these duplication setting are about and how they affect rendering, I think an expansion of this answer is in order

These are to create dupliverts, dupliedges and duplifaces.

Oh goodie, this one is tricky. I copied parts of a sphere out of it, and it was set to group. Setting it to none made the object appear.

I tried all the answers in this thread, but in v2.91, it appears that we do not have the Duplicate submenu anymore. So in the object that is not rendered, go to object properties, and check under Instancing that the Render checkbox is ticked.

Alternatively, next time you can check to see if anything has been disabled from being rendered. Just bring up the Outliner and look to see if the camera beside it is grayed out. I myself sometimes hit this by accident sometimes.
The shortcut to do this is Ctrl + H to turn rendering off.
Ctrl+Alt + H to turn it back on.
The other two are the eye and the cursor which means an object is invisible and disabled from being selected respectively.

When the camera icon is green, what does it mean?


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Why is this anti-aliasing artefact happening?
Shown below is a render of a model of mine.

Larger version here
As you can see in the circled portions, the anti-aliasing is pretty bad. How do I improve it?
I've tried increasing the samples per pixel and the sample width, but neither seem to help it. Is there any other way to correct it?

Here's a screenshot of the render panel: https://i.sstatic.net/SHZqf.png . File is here

Changing the quality lower makes it slightly better, but it is still noticeable and the rest of the image's quality goes down.

just saw the link, remember you can shift+b to render only a small portion ..for debugging. am checking now

Looks like you have transparency on the Island material, switching it off seems to do the trick,

This works. I'm not sure how the transparency got turned on.

cool! sometimes accidental keystrokes.. who knows.


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How to know what object the snap function is targeting (in Python)?
When using the snapping function during a translation in a script, is there a way to know which object, vertex, edge, or face was used as the snapping target?

Please correct me if I'm wrong (and roll back my edit), but it seems you are asking how to do this programmatically, correct?

Yes, I would like the snap function to return the object name with face/vertex index that it used for the transform operation.

The problem here is that snapping is an interactive operation, so to what is snapped to is known inside of the transform operator somwhow. But operators don't expose their internal working data, and bpy.context.active_operator.properties doesn't contain enough to find out (in particular if closest snapping is used, it may move your object to the same location for different snapping locations).
You can find the snapping co easily for snap to active, but it won't tell you which object nor which geometry element it used.
Would a scripted snapping modal operator help? Probably much slower than the built-in snapping, but that's probably the only way to know what is snapped to (requires a lot of final bmeshes in memory I guess).

Sounds to get in the right directions, but how could launching the translate operator in modal mode help to get the target? The goal would be to have a "stick" function which would parent or add a constraint to make the snapped object stick to it's target after user chooses the point/face/edge.

So the workflow for the end user would be: "Pick" (snap) a vertex/edge/face of an object, which is not selected/active. Immediately after that, parent the active object to the object which was used for snapping (or add a constraint to the active ob). Did I get that right? Is there another final step, which moves the active object?

so the work-flow would be intuitive: 1) Grab (G) object A (to be sticked) 2) choose the point/edge/face (from object B) to stick the object too (left click, snapping on) 3) The script take the object (B) the user snapped to make parenting (then moving B will move A as if it was sticked too it)

I see, it's basically a translation with snapping enabled + parenting the snapped object to the snapping object - in one go. A is grabbed and moved, B stays, but will afterwards move together if A is moved. Sounds good, but we really don't know to which object we snapped A. I can only think of a brute-force approach: granted A's center was moved to snapping location (not the case with CLOSEST!), ray_cast the scene using start = ob.location and `end = ob.location +/- threshold in 6 directions until an object is hit and isn't A itself. Did a quick test in console and seems possible.

Maybe if the involved C code changes is small enough (make translate/snap function just return the snap target), it would spare a lot of workaround ? I have no clue about C, but I guess returning a value is not that hard ? If you get it reliable in python I'm ok, but maybe asking the devs would be easier ?

Sounds simple, but the overall design of operators doesn't actually allow for this. Or are there hidden operator properties we could abuse? It would end up as a hack either way... Maybe add a context member, like bpy.context.scene.last_snapped_object :/

Yes. You can know.
It largely depends on the viewport you're in or the user view you're looking from. I think it doesn't give any visual indication as to where it'll be going next or sort but when it snaps to a face, edge, and or vertex, it happens visually for you to see immediately

The question is related to Python, not to using the viewport.

As RolandiXor said, it's a python question. But thanks for taking time to answer Rexford.


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How to use snap option in object mode?
Trying to use the snap functions, I don't really understand how the "part to snap" option works in object mode and how to accomplish a precise snap.

Closest is working as expected.
and 3. Center and median : I couldn't notice the difference. I would await "center" to snap the origin on the target (that's the case in all my test), but then "median" should snap the "middle of the mesh" to the target ? At the end, on my computer with 2.68, both do the same. Wrong configuration or bug ?
"Active", the one I need the most. I would await it to snap the active vert/edge/face in the mesh. But it does like "Center" and "Median", it snaps the origin to the target :/ Maybe the "active thing" is the object and not the vert at that moment, but it makes no sense to have 3 different options that do the same and really not what is expected ? It works in Edit Mode.

What am I doing wrong ? If it has to stay so, maybe explain why and a way to accomplish 4) in object mode would be great.

Object Mode Snapping:

Center
When in Object mode, "Center" for snap means taking the current Pivot point setting of your selection, which also means the transformation center, not the bounding box center of your selection.
Median
As for "median", it means the same as the Pivot type Median.
Median means a sort of center of gravity of the selection. The behavior is most obvious with an  asymmetric selection:

There is one way to get the same result by using "Center" and "Median" snapping,  which is when using Center snapping mode, if your Pivot point setting is Median, then it behaves the same as when using "Median" snapping mode.
In any other case, they will not be same unless your selected objects are distributed perfectly even with each other.
Vert/edge/face

Vert/edge/face are only available in Edit mode. So, don't think about it in Object mode, when in object mode, unless you are using "Closet" as snap target (available for vertex). your snap target "Active" will only be the origin of the one you selected last. Furthermore, make sure you do have a object that is selected and activated, otherwise blender has nothing available to snap, but to use "Median" point as the alternative one.
I hope I've tried my best to answer every point in your question. Of course, if any question, just throw it here, we'll try to offer further help. :)

P.S.: If you really need to snap certain element (vert/edge/face) in Object mode, you may consider switching to Edit Mode first, place/snap 3D cursor to wherever you want, then go back to Object Mode, using Center as snap target. Then switch Pivot point to 3D Cursor, which may behave as you expected.

AFAIK Vert/Edge/Face snapping is available in object mode?

@gandalf3, I bet he or she means the vert/edge/face on the one that is being transformed.

@LeonCheung ah, you are probably right..

Yep, verts/edge/face on the one being transformed, that's right.

To accomplish 4, you could A select the entire mesh in Edit mode, then enable snapping:

Now you can snap the entire object to another object (To a face, edge, or vertex, depending on the settings)

Then to reset the origin, Shift+Ctrl+Alt+C > Origin to Geometry, or T > Tool Shelf > Origin > Origin to Geometry

Thanks Gandalf, but the question was about doing it in object mode. Edit mode gives a mess when meshes are instantiated (all instances are moved)

That is a limitation, you might be able make them single user than re link them

From the Snap Target section of the wiki:

Active
move the active element (vertex in Edit mode, object in Object mode) to the target.
Median
move the median of the selection to the target.
Center
move the current transformation center to the target. Can be used with 3D > cursor to snap with an offset.
Closest
move the closest point of the selection to the target.

By "transformation center" they are referring to the Pivot Point, which defaults to Median, hence the difference not being immediately noticeable.

Please add some detail to your answer explaining what's contained in the link. If the link goes down, so does your answer.

Thanks, but the given links are about "pivot center", which is not what I'm looking for and the one about snap doesn't give more info on the reason why there are 3 different names for, in the end, 3 times the same function in Object mode. I must be doing something wrong, Devs have little time, they won't code 3 time a function under 3 different names in a single list menu. So it's either a bug, or I don't understand the differences.

I do think the wiki links conains all explanation for you on the three references. esp. Median. It would be harly possible for you to still puzlling on it after carefully reading the links (see the examples there). But Aldrik is also right.

Actually, I already had a look to the wiki before asking here. You seemed so sure about your answer, that I tried further. After trying a while to see the differences, I noticed that those descriptions from wiki only works when multiple objects are selected. That must be why Active, centre and median do the exact same thing with one object. I'll play more with it to understand how it all works and if I can do what I want with it.

Well, I'll try to explain in my way as I can.


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Bend Pivot Center of Rotation
I'm trying to use the Bend modifier along with an array modifier and appropriate pivot objects to take a plane and turn it into a segmented ring.
So I use an “array pivot” object to rotate the array copies, and an “bend pivot” to reposition the center of the bend modifier.
But I don't understand where exactly to position the bend pivot object. By experiment I found approximate solutions for various bend angles, and used python to fit a curve to the data, and determined the relationship is roughly -114.563/x, where x is the angle of rotation.
But that -114.563 makes no sense to me, I assumed there was some factor of pi or something that could explain how to position the bend modifier, but it still looks like a mystery to me.
So I was wondering, does anyone know what the relationship is? Or is there something I am missing that would make sense of this, or simplify it?
Edit: It just occurred to me that my factor is really close to 360/pi, so I think that is the answer, though the question remains, why does the bend modifier's center have to be offset different amounts depending on the degree of bend? And why the factor of 360/pi?

The equation that describes the Y coordinate of the bending pivot could be:

Where:

R is the wanted radius (in Blender unit)
BBsize.x is the bounding box size (in Blender units) on the X axis of the undeformed object
Theta is the angle of deformation (in radians)

If I would like to know, for example, where to put the bending pivot for the default plane (BBsize.z = 2 units) bended by one radiant (57,2958°) around a  circumference with a 3 units Radius, I'll get:
3-2/1= 1 units

If I want to increase the Radius to 5, I must move the pivot point in Y =
5-2/1 = 3 units

Changing the deformation angle to 45° (0,785398 rad) would mean changing the coordinate to:
5-2/0.785398 = 2.45352038075 units

Final result for the latest set of values:

Note that, as in the provided result we are using the world origin as the ring center, we can get rid from the dipendency of R, so the location of the Bending pivot is:
5-(5-2/0.785398) = 2/0.785398 = 2.54647961925 units

Here's a file with a bunch of drivers that change the deformation angle and the bending pivot accordling to the number of elements composing the ring that you can examine:

You can get away with just using the array modifier and an empty as the offset object.
Then just rotate/move/scale the empty(uncheck relative offset)

https://www.blender.org/manual/modeling/modifiers/generate/array.html

Thanks, but I'm already doing that — the point of using the bend modifier is so that the edges of the planes of the array will align perfectly, making a continuous ring.


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Colorizing part of a texture
I'm creating a crowd of people in Blender. For now, they all have the same model, and I want to create some variation by changing the colour of their clothing. What I have is a texture, a mask for each piece of clothing, and a randomly chosen colour. What I would like is to be able to use these to create a new texture like so:

Of course I can create each texture by hand, but I'd rather write some script that performs these tasks automatically in Blender. I also want to avoid a directory full of textures, as I can easily create those myself. What would be a good approach for this?
I'm using Blender Internal, and GLSL shading in the viewport. It's important that the viewport also reflects the colour, as I'll be using this in a live demo.
UPDATE: By using material nodes (as suggested by @chebhou) I almost got it working. This is the material node setup now. The material referred to in the "Material" node is actually simply a white textureless material.

The one thing that's left is to ensure that each object has a unique value for the HSV converter inputs. Does anyone have any ideas about this?

UPDATE 2:
Chebhou writes: I have tried to use the driver on the value node but it's not evaluated ( it's just stuck at a certain value) , and i need to make this value specific to each object (there are many objects that use this material but needs to look different )
I'm looking for a way to get an object related value like in cycles :

it would be good also if there is another approach(I can go through the objects and assign this material with different settings but it would be better if it is only one shared )
UPDATE 3:
Sybren writes: What I have so far is working nicely, check the video at  https://www.youtube.com/watch?v=BBlS4PKJhOc
However, it still uses the same values for all objects that use the material :(

You could try texture node's, instead of a script

According to the manual, texture nodes don't work in the viewport, so that's not an option for me.

@Sybren so you want the texture to be generated (during display) without using nodes and could be displayed in the viewport?

well, texture nodes don't work in the viewport, so that's why I don't want texture nodes. It has to work in the viewport too.

this is not a total script but it does the job :

in the default scene (or empty one) create this compositor node setup

you need to run this script just to have random numbers available in the driver :

import bpy
import random

def rand():
    return random.uniform(0,1)

bpy.app.driver_namespace['rand'] = rand

now add a driver for the value nodes with the scripted expression rand()
set the number of frames to render to the number of textures
render the animation and you'll have the output directory full with textures

Thanks for your answer. It seems useful, but I was trying to avoid having a directory full of textures, and do the shading in Blender itself.

what about material nodes with the same setup

It took a while to figure out how to hook them up, but it works, thanks. Now there's one thing left, and that's assigning the colour values. I've updated my post to reflect this (also includes a screenshot of the node setup).

@Sybren is it okay to have a different materials for each object ?

I'm experimenting with this now. I can use mat.node_tree.nodes['colourizer'].inputs['H'].default_value = random.uniform(0, 1) to get a random hue. This can be done for each material, and I can clone materials for each object. It would be sweet though if I could use a single material that picks up properties from the object it's applied to.


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Apply armature's object rotation to animation data
I'm trying to rotate a walking animation. It's stored as motion capture data in a BVH file (download an example here), and then loaded into Blender as a moving armature. What I would like is to be able to (manually) edit the animation. My approach so far was:

Load the BVH.
Move the armature object (so in Object mode) such that at frame #1 it's at the origin.
Rotate the object around the origin (so still in Object mode), such that the walking animation is aligned with the X-axis.
Press [Ctrl]+[A] to apply the location + rotation.

This last step doesn't do what I want. Rather than modifying the animation data, it modifies the armature itself. When I go to edit mode, I see that the edit bones have been changed (see before/after image).

Since I have multiple BVH files with multiple motions, this is a problem. Since the motion data itself isn't changed, it's impossible to use the aligned animations as actions, and I cannot link those edited actions to a single armature.
My question to you: how do I apply my alignment (rotations & translations) to the animation data (i.e. the root bone translation/rotation), while keeping the armature itself unchanged?
Sybren
PS: I've also asked this question at BlenderArtists. I'll make sure that if there is a solution posted here, I'll update my post there, and vice versa.

The answer lies in the MakeHuman Blender tools. There are a few steps you need to get right, though:

Load a BVH with the "Load BVH" button in the "Misc" tab. This will cause the BVH to be loaded incorrectly, as it'll be scaled down. Unfortunately you can only change this behaviour after you loaded the BVH. We'll fix this, and then re-load the BVH correctly.
Open the "MakeWalk: Options" panel.
Deselect the "Auto Scale" checkbox and/or set the scale to 1.00.
Scroll down to the "MakeWalk: Utilities" panel and click "Save defaults".
Remove the armature from the scene, and load your BVH again.
Open "MakeWalk: Edit Actions" and enable "Global Edit".

Now you can go to Pose Mode, move the armature around, and click on the "Shift Animation" button. Contrary to its name, this also applies rotations. It then applies your translation & rotation to the entire animation.


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Can blender do "deep compositing"?
Maxwell Render explanation of deep render and showcase of it
Was wondering, can Blender do "Deep" rendering to EXR, where an EXR file has 3D depth to it? If you go to 1:50 of the video you will see what deep rendering is in it's full awesomeness.

I'm not really sure what makes the image "3D" in the Maxwell render, but I know that you can fake lighting in Blender if you render out the normal pass kinda like they were doing in the video.

Not quite, their is the z-depth hack, but their is no true deep compositeing method to-date.

You can get depth information and use it the compositor (e.g. with the Z combine node) or put it in an EXR layer.
However there is no support currently for true deep compositing, which allows for transparency and compositing tricky things such as a motion blurred object.
I don't see it on any of the todos, however it's being mentioned in the mailing lists a bit, so it's hopefully only a matter of time.

If all you need is depth information, then it's currently possible:
The Z output contains depth information. It appears white since most of it's values are greater than 1. To view it, you need to map it's range to the 0-1 range, so you can use a Map range node or a Normalize node:

If you want to put it in an EXR, enable Z buffer in Render settings > Output:

You can use this with the Z combine node, which combines images based on Z depth values. For example, with two renderlayers (one with a sphere and one with some random objects), I can render them separately and then combine them almost as if I rendered them as one:


text:
Baking In Cycles creates noisy result
Whenever I try to bake a Ambient Occlusion map (no matter the scale), I get a noisy result (like that of a TV set with bad reception). Is there anyway to fix this??
This is a AO Bake of an object i'm working on, yet when I baked it at 2048x2048, the AO was very noisy/grainy.
Click image for full size.

https://i.sstatic.net/18xjP.png UV in full resolution.

Related: http://blender.stackexchange.com/q/4980/599

That's probably because a low number of samples. Cycles uses samples to render and to bake. Turn up your samples in the Properties window under the Samples heading.

Ohh!!! I didn't know sampling still effected baking! awesome! thank you!

No problem! If this answered your question, please mark it as the answer on the left. ;)


text:
Removing corrupt screen setting
In the UI I for some reason have one Model and one Model.001 where the later on is corrupt. When selecting this screen the UI freezes and the only way to get out of it is to use the Ctrl←/→ keys.
The blend file is binary so I can't edit it out manually. Is there a way to remove this?
Blender 2.68a

Reload startup file Ctrl-N (or any file, actually) not containing the corrupted screen layout. Reopen the problematic file but clear Load UI checkbox, under Open Blender File settings group in the file open dialog. Then save the file.
With Load UI unchecked, Blender will reuse UI settings from previously opened file, for the file to be loaded.

I keep a small Python console open for these types of fixes:
bpy.data.screens['CorruptScreenName'].user_clear()

Note you must first leave the corrupt screen, e.g CTRL-LEFTARROW. Alternately, bind a key to:
bpy.ops.screen.delete()

see: https://developer.blender.org/T36175


text:
Removing corrupt object
I have a corrupt object in my master scene. It can't be seen anywhere else than in the outliner. I can select it (in the outliner) but I can't delete it.
It happen to be so that this corrupt/lost object is in all my blender files because they where based on the same blender file.
I know I can Append/Link all objects into a new blender file, but the problem is that I have quite some node setups in the compositor. The only way to append them is to append the scene itself but that will also include my corrupted object.
I tried to copy/paste the nodes into the new blend file, but all my node groups complained about an empty datablock, so that didn't work either.
Any ideas?
I'm using Blender 2.68a with Cycles.

Aren't node groups (compositor or material) included in the Node tree folder when appending?

I found a solution to it :)
In the Outliner, change from "All Scenes" to "Blender File" right click on the corrupted object and select "Delete". Now it is deleted...

You're having some weird problems ;) are you using a build downloaded from blender.org or builder.blender.org?

No I use the official binary from blender.org

If you know the name, you could also use the Python Console I guess.


text:
How to save an image without antialiasing in cycles?
I think this question has been raised numerous of times, but I have yet not found an answer that works.
I'm rendering game graphics with cycles and I need them to be saved in RGB, without any alpha information what so ever.
Setup:

I want to save this picture, exactly as it appears here, with no alpha. But it always saves an antialiased version of it against black.
How can I save the image without antialiased result?

could you add two small images with how the result looks right now and exactly how you want it to look?

Just to be clear, I don't think the antialiasing is stored as alpha values in a single layer PNG, rather just a mix of whatever color and black (in RGB colors). So with the settings you have now, there is no alpha information being saved.

@Gandalf3 I need the object to not be antialised against the background, but still within the object itself. So far Peter's solution worked best for me.

@MaxKielland I agree PeterT's solution is better, but my solution should work for doing that.

I assume you still want AA within the image, just not at the borders, so I'd suggest that you render with a transparent background and remove the border AA in the compositor:

There's obviously ugly aliasing artifacts here but you could fine-tune the "Greater Than" Node or process multiple alpha ranges differently.

I went for this solution. It was independent of the objects and I see how it works, I can fine tune it. Thanks!

Is there any advantage to using Image > Separate RGBA > Alpha instead of using the Alpha socket of the RenderLayers node?

@WChargin nope, I just threw this together, you obviously don't need the RGB node either, since you can set the color on the empty image slot on the Mix node itself

To make the background transparent, connect "Greather Than" output to "Composite" Alpha socket. Also, "Set Alpha" node is not required.

In 2.67 and 2.68a (I haven't checked 2.69+), the amount of AA present in the cycles render is controlled by the size of the Gaussian sample on the film.
The gaussian for the film is the amount of jitter that rays leaving the camera receive. If this is high, the pixel effectively samples a little circle of incoming light in the scene, and you get anti-aliasing. If this is small, then all the rays are almost the same, and you are sampling one single point on the film.
So to reduce or remove anti-aliasing in Cycles, turn down the Gaussian width in the Film section of the Render settings. Turning it to 0 will reset it to its minimum (currently 0.01 on my version, the default is 1.50), and rendering will give essentially a non AA image.

If you just want to avoid an aliased outline, then this isn't the right setting, do it in the compositor as per PeterT's answer.

Another way to remove anti-aliasing in cycles is with composite nodes and ID Masks:

Enable Object Index in Renderlayers > Passes:

Set the pass index  of all the objects to 1 by

A> Select all (to ensure you have all objects selected, you may also need to un-hide hidden objects (AltH) and toggle all layers visible (~))
Set Object Data > Relations > Pass Index to 1
Right click on the Pass index setting, and select Copy to selected:

This will add a new output to the Renderlayer node. By plugging it into an Id Mask node and setting the Index to 1, you can generate a mask of all the objects. This mask will not be antialiased when the Anti-Aliasing option is disabled:

Use the resulting aliased mask as a Mix factor to remove anti-aliasing from the render. This will only remove anti-aliasing from the edges next to the sky, leaving the edges over other objects smooth:

Result:

Just as a side-note, if there's not transparent surfaces this gives almost the same results as filtering for alpha>0.5 meaning that it will still contain some pixels mixed with the background color if cycles is set to use AA, but they're fairly unnoticeable compared to what the default output gives you.

@PeterT Your solution is better, +1 :)

objectively it can go both ways, with your method you don't get these artifacts on straight lines. But using "Greater Than" values of 0.85 seems to be a good compromise.

I did tried this one too, but at a first glance Peter's solution seemed to give me more control and I don't have to fiddle with the index for each object. Thank you any way..

@MaxKielland PeterT's answer is the better one, but I have updated this answer anyway. (you shouldn't have to fiddle with the the pass index for individual objects, so I tried to clarify)

I did try out your solution and it works probably perfectly all right in some applications, but for me I got a one pixel dark rim and no way of adjustments.

@MaxKielland Odd.. and Anti-aliasing was disabled on the ID Mask node?

Yes, it was. As I said it doesn't do the full trick for my specific application. I have a lot of lines in 26 degree angels... I'm sure it works perfectly well in other situations.

The Anti-Aliasing option does nothing for the Cycles renderer, it's only for the OpenGL renderer (=viewport render).
If you wanna have a Cycles render with no AA, try this:

Sampling panel, set from Path Tracing to Branched Path Tracing
Set AA Samples to 1
In the Film panel, untick Transparent
Save in RGB mode

Note that GPU does not work with the non-progressive integrator (it does in the RC, but the OP's screen-shot is of an older version)

It sort of worked in 2.69 RC1, but it could occasionally crash on Windows (which is really a Windows problem, stupid timeout error whereby OS believes the GPU crashed if it doesn't respond fast enough and resets driver).

Is this for Blender 2.69RC? I on 2.68.


text:
How to snap part of a mesh to the grid?
I have an I-Beam where one end is on the grid and the other end is between grid lines. When I turn on "snap to grid" and moves all vertexes in the other end it snaps in grid increments, not to the grid itself.
Do I really have to create a dummy on the grid to be able to snap to it?
Blender v2.69
EDIT
I'm aware of ShiftS and it works fine for simple meshes.  However this is what happens if you try the "Snap selected to grid" on a complex mesh:

What version of blender are you using? Selection to grid works fine for me in 2.69.

You can CtrlAltQ to toggle Quad View, then click to the nearest grid crossing to place 3D Cursor there, then ShiftS > Cursor to Grid to snap the 3D Cursor in two of the side views (to snap it precisely to the grid dimension as you want). Then, ShiftS > Selection to Cursor (Offset) to offset the selection to the 3D Curor, without collapsing:

NOTE: Snapping cursor to grid currently depends much on the view zooming, in other words, the visual grid scale, so, if it cannot be easily snapped to the crossing, just give it another try after zooming in or out.

UPDATE: For your concern in the comment, you can temporarily add an empty to assist snapping:

This looks like an effective way to do it, but it fails if the objects center isn't in right on the grid. If you move youre model down a bit and do the same you will see that the I-Beam "side" snap its center to the grid. If it isn't in center already, the model will be skewed.

@MaxKielland OK. Then I would suggest a relatively quick way to do this, see the updated answer.

Method 1:
Press ShiftS>Selection to Grid.

For example:

Method 2:
As an expansion of Leon Cheung's answer:

Snap the cursor to the selection:

Snap the cursor to grid

Snap the selection to the cursor with the Offset option

The selection is now aligned with the grid, so you can snap using the normal increment snap.

It doesn't work for a complex shape like an I-Beam. All  selected vertices snapps to the same point nearest point, deforming the whole object. I will see if I can update with pictures.

I have updated my question with a picture of the SHIFT-S problem.

You can do this in orthographic mode and it uses the grid size of the current zoom level, (however we could add some grid-division option for the snap tool as well.)

It still snapps in grid increments, not to the actual grid itself. All I really want is so simple, press G to move the vertices, lock an axle and snap to the visual grid, without moving any vertice in any other direction than the locked one. How hard can it be?!?

@ideasman42 Or a 'Selection to Grid (Offset)' option?

@RayMairlot The default option seems to behave that way for me (in the 2.7 RC)..

@gandalf3 ah yes, you are right. I had presumed it didn't work like that from the screenshot in the question.

@MaxKielland Exactly, extremely frustrating that they cant such a simple thing right.  i cant find an answer that explains how to do it. Blender really seem to have messed up snapping, its over convoluted yet cant do basic stuff

@nights There is now a more convenient snap to grid option, I can't update my answer atm but try this answer: https://blender.stackexchange.com/a/177745/599

You can snap the cursor to the grid and add a plane at the cursor, merge all points of the plane into a single vertex. Than you can use vertex snap to snap the geometry to the plane.

Place the cursor some place near the grid point you wish to snap the geometry to.

Snap the cursor to the grid point

Add a plane whilst still in edit mode. With the plane selected merge all vertices at center

Now use vertex snap to snap your geometry to the vertex.

Make sure to delete the vertex when you are done with it.

Yes, this was what I meant with "create a dummy object". It is a hell of trouble to do a such fundamental thing :)

This is the method that I use, its not ideal but it works fine. And I don't do this anyway on a regular basis

So you have to add extra geometry just to snap to grid? Crazy!


text:
Instance a different sets of geometry on different parts of mesh by index
I have a mesh circle that has some deleted verts. Each seperate curve of this must have a different instance of geometry instanced to it. For example there are 4 parts. Curve index 0 must have cubes, curve index 1 have spheres and so fourth. I have some working on a repeat zone but still struggling to get all the elements to show up.
Bear in mind I am using a repeat zone because the amount of segments of the circle will change (not set to 4, it could be 5 or 6, and the position of the deleted parts also adjusts dynamically.
Is there a way to do this without repeat zone ?
Thank you!

Reading again your question, do you have a Curve with many Splines as input geometry to the GN modifier ? Or do you have a Mesh with Islands ?

its a mesh with islands

(Using Blender 4.2.1)

1. Objects to spawn are collected by a Geometry to Instances node.
2. With activation of the Pick Instance property, the Instance Index is based on the Island Index of the spawning point.
The Instance Index value is computed as the Island Index modulo the number of instances in the collection. So with 4 islands and 3 objects to spawn, index 0 (the cube) is reused for mesh islands 0 and 3 (because 0 mod 3 = 3 mod 3 = 0). Consequently, this setup is dynamic whatever the number of islands and the collection size.
Resources:
(Blender 4.2.1+)

you are a wizard. It was so much simpler than I was trying with repeat zones and nested zones. Cheers!


text:
I applied an array modifier, joined the parts together, but the pieces are not connected
I feel like I've done everything to try to fix this issue (merge vertices by distance, change origin, I've tried to remesh but it ruins topology...
I made the belt using an array modifier (which I applied) the pieces act like they are one most of the time... should I be worried about how the armature will affect the belt when I add one or is this fine as is?
(see pictures below)

Can you share your Blender project file? Instructions for sharing.

the Array modifier has a merge option. Had you ticked it before you applied the modifier? A Merge by Distance should work, too, if the distance between the verts is not too big. You can change the distance in the popup at the bottom left corner of the viewport.

Thank you! changing the distance in the popup worked! (It was set to 0.001 for some reason...)


text:
How do I quickly create empty vertex groups for a collection of specific bones?
I just want to be able to select a few specific bones and create empty vertex groups for them. This way I can select the specific vertices I want to weight paint in edit mode, click on the vertex group I want, and press assign to neatly weight paint certain areas. I know that, if I weight paint the bones by hand, a vertex group will be automatically created for them. What is a simple way to go about doing this without making them one-by-one? Ideally I wouldn't have to parent the entire armature with empty groups.

in object mode, if you select the mesh and then armature (parent of all bones), and then use Object >> Parent >> "Armature -- deform with auto weight" (or as you want "with Empty groups"  -- all is done for you.  There are many tutorials on youtube and you can search in this forum.

I know how to parent an armature with automatic or empty weights. I am asking if there's a way to create empty weights for some bones and not all of them. I am currently working on my model's hands and it would be easy to just add all the vertex groups for such a dense part all together instead of one by one. I have it parented with zero vertex groups to begin with, for the sake of not having to scroll through all the vertex groups that I'm not working on yet. If this isn't possible I imagine it would just be easier to have all the empty vertex groups to begin with.

I actually wrote a script recently for work that does a similar thing, I modified it a bit to fit your specific needs. It should work. Just run it in your script editor with Alt+P, then you should be able to search for it in your F3 operator search. If not, make sure you have Developer extras and Python tooltips enabled in Preferences -> Interface.
It's meant to be run in pose mode with at least one selected pose bone and one selected mesh object.
import bpy

def get_objects(context):
    objs_to_parent = []
    armature = None
    for obj in context.selected_objects:
        if obj.type == "MESH":
            objs_to_parent.append(obj)
        elif obj.type == "ARMATURE" and armature is None:
            armature = obj
    return armature, objs_to_parent

def main(context):
    C = context
    armature, objs = get_objects(C)
    bones = C.selected_pose_bones
    obj = objs[0]
    for bone in bones:
        vg = obj.vertex_groups.new(name=bone.name)

def get_obj_types(context):
    return [obj.type for obj in context.selected_objects]

def poll_op(context):
    types = get_obj_types(context)
    if context.mode != "POSE":
        return False
    if context.active_pose_bone is None:
        return False
    if "ARMATURE" not in types:
        return False
    if "MESH" not in types:
        return False
    if len(context.selected_objects) < 2:
        return False
    return True

class RIG_OT_quick_create_empty_vgs(bpy.types.Operator):
    """Quickly add empty vertex groups for selected bones to the selected mesh object.
    Requires pose mode with selected bones, and a selected mesh object."""
    bl_idname = "pose.quick_create_empty_vgs"
    bl_label = "Create Empty VGs For Bones"
    bl_options = {"REGISTER", "UNDO"}

    @classmethod
    def poll(cls, context):
        return poll_op(context)

    def execute(self, context):
        types = get_obj_types(context)
        if types.count("MESH") > 1:
            self.report({"ERROR"}, "Only one mesh object should be selected!")
            return {"CANCELLED"}
        main(context)
        return {"FINISHED"}

def register():
    bpy.utils.register_class(RIG_OT_quick_create_empty_vgs)

def unregister():
    bpy.utils.unregister_class(RIG_OT_quick_create_empty_vgs)

if __name__ == "__main__":
    register()


text:
Move a texture towards the center of UV (vortex) on a flat surface without scaling
So basically I'm trying to make a flat portal/vortex wich looks like the typical hyperspace loop with only a texture.
Here is the texture and the effect I'm looking for:

I was thinking about stretching the image along the Z axis of the UV center but I dont really know how

maybe simply create a cylinder and stretch a noise along its length?

@moonboots I wanted to know if its possible to do such thing with only shader nodes because I know you can modify the mesh to be the actual wormhole and just slide the texture or play with the UVs to get the same effect.


text:
Trying to make simple 90 degree elbow pipe, having issue with Bridge Edge Loops
Goal: I want a 90 degree elbow pipe.
Issue: Bridge Edge Loops is responding differently than tutorials, not returning a 90 degree bend from surface to surface, and I don't understand why.
General: I am fairly new to blender.

After performing the operation, look to the popup menu to the bottom left. Expand it and increase the number of cuts to get it to become an elbow.
On another note, I don't recommend you leaving the faces from your cylinder end caps in place prior to performing the bridge. You should almost certainly delete them before proceeding, or else you'll end up with non-manifold geometry, meaning that later rendering efforts could get glitchy.

"You should almost certainly delete them" Why bother to delete the faces? The Bridge Edge Loops tool removes them automatically so there is no non-manifold geometry afterwards... did you not notice that?

I did not. Thanks for explaining that.

As the other answer already explained, you have to increase the number of Cuts in Bridge Edge Loops tool, I do not know what they tell in the tutorials you were watching, but your screenshot shows 0 cuts and without you cannot build a smooth transition.
Speaking of smooth transitions: the Smoothness default value in the tool is 1, and below you can see what this looks like on the left compared to what I think 90° elbow pipes look like on the right.

Of course if the two pipe pieces are further apart, the bend might not be overlapping that much, but it will never look like the profile was really rotated by 90°. Therefore you have to adjust the Smoothness value to around 0.585 (a long time ago I tried to find a mathematically exact value but I do not know how Blender calculates this smoothness so I failed).

Nevertheless, the Bridge Edge Loops tool is good to get smooth transitions between edge loops even if they have different shapes. But depending on how you want or have to create the elbow pipes, maybe the Spin tool might be interesting for you as well.
Take the following example, this looks a bit complicated but only if you want to have specific defined dimensions of the pipe, which I am going to demonstrate.
I only have a piece of vertical pipe. In my case, I know the center of the top edge loop is at (0, 0, 1) and I want the pipe to continue after a 90° turn with the center at (0, 2, 3). Then I have to spin the top edge loop by 90° on the X axis around a pivot point at (0, 2, 1).

So what I do is activate the Spin tool, set a number of Steps of whatever number of segments I want and choose the X axis for spinning.

Because I want the pipe to continue to the right, I grab the right red circle with the Plus symbol and drag it to the right. This looks terrible at first, because the current position of the 3D Cursor is the pivot point, but that does not matter. You could hold the Ctrl key to rotate in 5° steps to ensure you get the 90° accurate, but for now that does not matter either.

It does not matter because after you release the spin however far you have dragged it by now, the tool options panel appears at the bottom left of the 3D Viewport. There you can set the Angle to 90° and Center XYZ i.e. the pivot point of the rotation to (0, 2, 1) just as needed (and you can still change the number of Steps there as well).

After spinning you can simply extrude the edge loop with the shortcut E in normal direction (if you have a closed face) or by pressing Y constrained to the Y axis (if you have an open edge loop).

This sounded more complicated then it is and is only necessary if you want well-defined positions for the pipe parts. Of course you could simply eyeball it until you have something you like by rotating it to the desired angle and then moving the Center either along the axes with the large arrows of the tool or freely by hovering your mouse over the yellow center ring so that it turns white, then grabbing and moving it:

For some reason, after getting some sleep and trying again, opening blender from scratch, it worked well. Your tutorial is incredible, I appreciate the time you have put into this post. You are the best!


text:
After updating to Blender 2.68 Driver Scripts are no longer automatically excecuted
When loading a .blend file the console window shows error messages like:
skipping driver 'x1*(1-x2)', automatic scripts are disabled
skipping driver 'x1*(1-x2*x3)', automatic scripts are disabled
skipping driver 'x1*(1-x2)', automatic scripts are disabled
skipping driver 'x1*(1-x2*x3)', automatic scripts are disabled

In the file browser the option Trusted Source can be set but isn't remembered when using File: Open Recent

Can the new security features switched off?

You can turn this setting off in the user preferences by unchecking Auto Run Python Scripts:

See the wiki for more information.


text:
How can Waves of the Ocean Simulator flattened on a Beach Area?
I'm currently trying to flatten waves of the ocean simulator on a beach area using a lattice. But sometimes the end of the waves mesh becomes visible. When the influence of the lattice is increased too much it pulls the whole ocean to the beach.
What would be a better way to achieve this?
The images should illustrate the issues faced:

I just tried out using the shrinkwrap modifier and it worked. Set the mode to "project". You might have to make a separate mesh that the ocean shrinkwraps to that doesn't include those things that look like rocks and stuff.

Beyond that, you might also want to look into using fluid simulation or animating little waves or something similar if this isn't what you're after.

The lattice can be subdivided in the Properties > Object data tab:

This way the lattice influence can be left at 1.0:


text:
How can a path animation be used as an action in the game engine?
I animated a rollercoaster using a Bezier Curve and a Follow Path Constraint affecting the vehicle.
Then I tried to use the automatically created action in the game engine but the Action Actuator has no effect .

How can this action be used in the BGE?
Can the Path Animation alternatively be converted into keyframes?

You might be interested in this

You can convert actions such as constraints to keyframes with Object > Animation > Bake action. (see this)

You may want to enable Clear parents to replace parent/child with keyframes:

Also note that without Clear Constraints enabled, constraints will not be removed, possibly giving unexpected results.

Thanks for your quick response, which object(s) should be selected when baking the action? Baking the constraint leads to strange offsets which can't be relocated perhaps swaped axis. Baking the bezier-curve seems to move around the current position.

@stacker The object following the path should be baked. Make sure you remove the constraint(s) afterwards

Now the vehicle moves as expected, the view from the camera which is parented to the vehicle seems to be on the wrong track, but this would be another question. Thanks this helped much, everyday another mighty tool.

@stacker you might be able to fix that by enabling clear parents (I just tested and it seems to work) you can also automatically remove the constraints with clear constraints

Sorry that was one of my scripts for the (currently unpluged) head tracker it changed camera orientation to some weird settings. Now its fun, thanks again.


text:
How can a grid mesh be unwrapped to overlayed quads?
I have a grid mesh on the floor and want to UV map it to an image of 2x2 tiles.
I remember that there was an option which allows it to map all quads over another, but I no longer know what the name of the menu items was.

Between the tiles are joints (in case this makes a difference), detail view:

There are several addons for uv's. Maybe you haven't enabled it or haven't installed it into your current blender? Try the scripts folder next to the user config for older versions.

Starting with an unwrapped grid (without the joints), press U in Edit Mode to bring up the unwrap popup and chose Reset:

After scaling down all UVs to the size of a single tile they can be distributed by repeated Random Deselect from the Select Menu in Edit Mode


text:
How can faces be rotated around their individual normals?
In edit mode with these settings:

Face selection
Pivot point: individual origins
Transformation orientation: Normal

The faces don't rotate around the normals, is there another required setting that I overlooked?

You need to press a key to specify the axis. (i.e. X, Y or Z)
Setting the Transform orientation aligns the XYZ coordinates to something, e.g.:

Global aligns the axes to the world
Local aligns the axes to the selected object(s) rotation
Normal aligns the axes to the selected element(s) normal

etc.
Note that pressing the axis key once always snaps to the Global orientation, regardless of the setting in 3D view > Header. To use the orientation specified in 3D view > Header, press the axis key twice. (e.g. GZZ)
With your settings, (Individual origins, Normal, Face) to rotate each face around its normal we should rotate around the Z, see the wiki:

The z-axis of the manipulator will match the normal vector of the selected [element]

So by pressing RZZ:

Yes you can do this, all accessible from interface but included keys

Enter Editmode (Tab)
Change to face-editing (3)
Select all (A)
Mesh -> Edges -> Edge Split (CtrlE, D)
Change orientation to normal (,, 2)
Change pivot to individual origins (.,2)
Rotate about the Z axis `(R, ZZ) ... move mouse:

how would I do this in python?

That should be a separate question.

I have the answer :D

#python to rotate all faces

#rotate all faces on mesh by 1 degree
import bpy, bmesh,math
from mathutils import Matrix
bm = bmesh.new()
bm.from_mesh(bpy.data.objects['Cube'].data)
for face in bm.faces:

    axis = face.normal
    rot = Matrix.Rotation(math.radians(1) , 4, axis)
    cen = face.calc_center_bounds()
    mat = bpy.data.objects['Cube'].matrix_basis
    bmesh.ops.rotate(bm, cent=cen, matrix=rot, verts=face.verts,space = mat)

bm.to_mesh(bpy.data.objects['Cube'].data)
bm.free()


text:
Apply Texture Projection to Specific Pose (not Rest Position), While Keeping the Animation Intact
I want to apply texture projection on a game character from Adobe Mixamo. I started Blender with this game character, which includes an animation. Since the final result in my game will use the running animation, it makes sense to apply texturing via texture projection on a frame of this animation. However, when I try to project a texture onto my character, I see a pose/rest position that doesn't match the final position the game character takes in the end result. Applying a texture via texture projection on the pose/rest position skeleton isn't logical in this case.
What I have tried:
I tried changing the rest position to the desired pose where I want to project a texture on to (the first frame of my animation). Unfortunately, this resulted in the following warning: "Actions on armature will be destroyed by new rest pose." This is not what I want because, apart from the texture, everything is perfect, and I want everything to remain intact.
Some images for clarification:
The first frame of my animated model:

The image I want to project on it as a texture

Demonstrating the problem: What my model looks like when I open the UV editing tab (to perform texture projection)

How can perform texture projection on my model using the first frame of the animation as the pose?

You need to bake the projected texture to a mesh with UVs. Like this

@Jakemoyo thanks for your comment! I watched that video a few times but I am unsure how that could help me to project my 2d image onto my mesh (running pose). Could you elaborate further?

You project the image onto one model, then create a "low-poly" (not necessarily lower poly count, just one with 'real topo' and UV maps), that matches it and bake the diffuse from the projected model to the low-poly one. Then once it's in a texture it will stick to the low-poly models verts without projection.


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Can't find a way to use the grease pencil to directly draw filled shapes
I'm currently working on my workflow for a lightbox project (you can google Hari&Deepti to have an idea of what I'm looking to create), and I would like to create and render my projects in 3D before printing and cutting the paper layers to have better control over the design and the rendering.
I managed to create a nice render by drawing the layers in a separate software, then converting the lines to vector and importing them in Blender.
This is what I got :
Now, I would like to directly draw the layers in Blender with the grease pencil (or maybe there's a better option but I doubt it could be faster) to save time and have better artistic freedom.
I've been trying for few days but I just can't get it to work like I want. I can draw what I want, but then when I need to fill the areas it doesn't work :

I've tried a lot of things, playing with the filler tool options, making sure the material as the "fill" option enable, that my shape is correctly closed (still not sure how to shake that), etc... but nothing works.
Any help or guidance would be highly appreciated ! Thanks !


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2d Image sequence wont display frame by frame images
I am new to blender and I couldn't find anything online to help me with my issue.
I imported an image sequence, but I would like to be able to modify the images.
there is no display of the images on the timeline, is there a way to show them? or better is there a way to upload image as a single frame? that way i could just do it for the rest of the image sequence and edit whatever i want