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Nodes not visible for material created in properties panel
Materials created in material properties are not showing up in the node editor in blender 2.70.  Is there something I need to turn on?  I've looked in user preferences and I don't see anything obvious.

Here are some possible causes:

You're working in Blender Internal rather than cycles:
You're working with the compositing nodes:
Make sure that the selected option is the little ball, not the one that's selected in the image.
Your view is not in the right place. Hit the Numpad . key on your number pad. If nothing happens, hit A then Numpad ..
Make sure use nodes is checked

I checked that before I asked the question and it was in the right position.  I had to restart the program and made sure it was in cycles from the start and that fixed the problem.  Thanks very much.

@Rmathews951 If this helped you, please mark it as accepted answer.

Or make sure the "Use Nodes" Checkbox is checked in the Node Editor.

I'm baffled by the nasty UI in blender.
You answer was correct. Thank you.

In Compositing tab, Find Nodes under Select in the menu. Reference from here.
Hope it helps.


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Is it possible to nagivate Blender viewport like with WASD in a video game?
In video games, flying in the level is typically like this:

W - move forward;
S - move backward;
A,D - move right/left without turning;
Space - jump/ascend;

If I try this in Blender, it does not work (and in general makes some mysterious hard-to-undo changes when I press unknown keys).

Is there any easy mode for navigating the scene using video-game-like controls?
Is there even mode video-gamish mode with gravity (towards the center of the closest big object) and clipping (not allowing point of view to become too close to some surfase)?

Try the Walk and Fly navigation tools (shown in the image).  Walk, in particular, allows you to temporarily navigate using the WASD combination

The shortcut is now Shift-`, for `2.79` use Shift-F. Then you can use WSAD.

in blender 2.8 the shortcut is SHIFT `

You can map this to a mouse button to make it more like other 3D software: I've answered here: https://blender.stackexchange.com/a/187570/101687

source: Stack Exchange

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

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sort: votes


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How to create a drilling effect?
I wan't to show a drill drilling into a surface. I can't however, create the effect of the surface being ripped up by the drill. I'm trying to animate the shavings of the surface, to give it a believable appearance
I've created the jaw and I've imported an .stl drill that will work for the video. I am able to do the basic animation, but when the drill is going into the mesh, I cant seem to figure out how to have the section of the mesh "follow" or be removed from the drill depth, meaning that the hole left over after drilling.

How about using a particle system to create some flakes of bone and a Boolean modifier for the hole? I'm not sure what you mean by "have the section of the mesh "follow" or be removed from the drill depth".

What I'm looking to do is drill a hole and when my animation moves the drill into the mesh, how do I show that section of mesh as removed? Basically I want to grow a hole.

There are several solutions (ideasman posted some, I could add dynamic paint with displacement), but they depend on the requisites of the animation. Do you need the bone, especially the section of the bone to be textured?

The following approaches could work well:
Boolean
(Where an invisible object is used to define the empty space), This is the most direct answer and it can probably be made to work, but also may have problems if the jaw is a non manifold mesh. As a workaround in your case you could remove a part of the jaw, add a inset that the boolean operates on, this makes the computations much more simple but then you need to make sure the seams between the inset and the rest of the geometry are not noticeable.
Deformation
Where a bone or shape key is used to deform the mesh to create the hole, this is fast and predictable but has some possible drawbacks. UV's & vertex-colors etc will distort with the mesh, drilling multiple holes in the one cavity (where the holes overlap) becomes difficult. (something boolean can do). The key to making deformation work here is creating the geometry so the deformation looks good. and you don't loose volume around the deformation in an unrealistic way.
Mesh replacement
Replace parts of the mesh over time by animating visibility, may seem a weak solution and has the disadvantage that the animation wont be smooth and you have to finalize the mesh before making duplicates.. but it gives a lot of control.
Other options which I think wouldn't work so well but including for completeness:
Compositing
Sometimes you can use the depth to do operations you might assume you would need to do on geometry, there are tutorials showing clever use of depth buffer for similar tasks.
Metaballs
For certain cases negative metaballs can be used well for this effect.

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


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Brighter SSS in Blender Internal
I'm working on BI materials for my model of a highlighter. I already have a Cycles version done. The SSS in Cycles looks good. The colour of the marker is intense, almost true fluorescent. I want to achieve the same result in BI. But the result is very dimmed. Is it possible to make it juicy as in Cycles? I noticed that when I turn on Environmental Lighting in BI then it looks very nice and intense too, but this is not the point. I need a material that will look good, not the lighting. See images as example of my settings.
Also, is it possible to further strengthen the BI mesh lights? They are already at 2, which is maximum, but the light is still dim.

There are many SSS preset. Did you try them? The difference of lighting between the two scene is considerable, it makes it difficoult to make a proper comparison between the shaders. About Blender Render shading Emit strenght see: http://blender.stackexchange.com/questions/2832/number-button-min-max-limits

I tried all the presets, none intensifies the effect really, it changes the color and appearance but not intensity. The Emit strength of the mesh lights worked however, I typed in a higher value.

Ok, after some trial and error and reading the Blender Wiki on SSS, I found a solution. It all depends on the Scattering Weight Front and Back parameters. I set them both up to 1.7 and the effect is much more juicy and brighter. As the Blender Wiki explains, these parameters are responsible for how much light is absorbed or added on the front and back side of the object.


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What is albedo and how to use it and how to prepare materials for games?
The main question is: how to prepare materials for games? Say I model an asset. Bake all material textures (diffuse, AO, specular etc.) into one diffuse, bake normals from a high poly version of the model into one normal map. Is that correct? Or should I do it differently, say prepare separate texture for specular. I read somewhere that in games there are actually no materials, only textures. Is that right? Also I came across the term albedo and that it is used in games/game engines? What is it exactly and how to do it in Blender?

Albedo is a Diffuse/Color map but without additional lights and shadows (AO) as @metaphor_set said. I've found a tutorial recently showing how to prepare a map like this using Photoshop: https://www.youtube.com/watch?v=VBoHh6CR-kM May be helpful for you.

IMHO there is no single right or wrong way in how to prepare materials for games. Sometimes the engine dictates what you should prepare and often you just follow personal preferences.
Your project might also require different types of spec maps, for dry and rainy weather, for example. Cavity maps can produce all sorts of fancy effects like dirt, dust, worn edges, snow on top of rocks...
I am a big fan of model recycling. Sometimes it's only a single part of a mesh, a fancy cycles material, but I also reuse complete models with textures. To get the necessary flexibility I bake huge textures and  separate maps - sometimes even for cavity.
Albedo is basically the new diffuse ;-) Since many people started baking all kinds of effects into their diffuse maps it just seems to make sense to give the plain color without lights, ao, whatever a new name. Basically it's a "normalized" version of the "modern" diffuse map.
Edit: You might watch Joel Burgess's GDC presentation about modular level design in Fallout 4. It's a great source of what can be achieved by reusing meshes with different material setups

Not normalized. Albedo is reflectance, and real world materials don't absorb or reflect light completely. Allegorithmic published a nice PBR guide which covers what Albedo is and included some "safe" values in case you don't have the information about the albedo value of the actual real world material.

@Gez - not in general. It depends on the material type. Not every render engine uses PBR and reflectance is done differently on different game engines. Even Allegorithmic doesn't use the term "albedo" consistently in their documentation.

That's why I mentioned the real world materials. If you don't have that data you can generalize a reflectance value. Allegorithmic in their PBR guide suggested some minimum and maximum values for as guidelines (i.e.: don't go below or above them respectively), but of course albedo depends on the actual material.
BTW, I was questioning your use of the word "normalized" in this context, as in "normalization".

Link to the PBR Guide @Gez was referring to: https://academy.substance3d.com/courses/the-pbr-guide-part-1


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What is and how to use a Fake GI Dome?
I've come across a concept of a fake GI dome. I would like to know what is it (is it the same as a sky dome, or is it rather an array of spot lights arranged in a hemisphere fashion, if so, how many lights should there be?). And what is the benefit of a fake GI dome? I understand it renders faster than true GI right, but how about the quality? Also, does it make any sense in Cycles, because Cycles uses GI sort of by default. I understand it does make sense in Blender Internal though.

It's been a very long time since I read about fake GI but as far as I can remember, Fake GI and light domes are two different approaches to get global illumination.
The goal of both methods is to create sort of a "50% grey" effect that illuminates the whole scene in a similar way cycles does when you render out the default cube with no additional light source in the scene. Ideally there would be no shadows at all since the light comes from all directions. Additional lights will then produce shadows which aren't completely black.
afaik Fake GI would use a skydome with maybe a fancy HDRI image slapped on that emits the light, while light domes are dome-like structures build out of actual light sources - many light sources.
I don't know if those methods are really that much faster to justify the amount of pita they require in terms of workflow (compared to modern render methods, that is), but most of the results I've seen are quality-wise somewhere in between Blender internal with Hemi + additional light sources and Cycles. The point is that shadows are still "harder" thus more unrealistic.


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Array modifier - why is the source object tripled?
I don't understand why is the source object: BaseDeco 1, tripled when I apply the array modifier, with offset based on an Empty (BaseDeco 1 Empty)? It is tripled - there are 3 sources from which the Array makes clones.
I thought the array should start from one object (in this case the BaseDeco 1 - when I go into edit mode, there is clearly only one piece), and go around making 20 copies, but it's tripled. Why and how to control it?
I simply need 20 copies going around the perimeter of the circle.
I'm attaching the Blend.

The modifier works as intended in the file. The pieces overlap on top of each other because of the amount of rotation in the Z axis of the Offset Object. If you wanted 20 copies around it you need to rotate the offset object 360°/20=18°:

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


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How to rotate object axis, leaving the object intact?
I need to adjust/rotate the axis of the object, not affecting the object rotation. Only rotate the axis. Is it possible, and how?
Explanation: As you can see on the image. I have a network of balls and connectors. I duplicated these elements using Shift+D and then rotated and adjusted so it all creates this network shape. Now I want to continue duplicating and adding more to the network, but now the axis are all messed up already. As drawn on the image, I can't rotate the one connector down anymore (marked in red). The axis are messed up. So I need to adjust the axis, so I can rotate around one of the axis, doesn't matter which one. I know about the Transform Orientation tools in the N panel. But I can't find any element which would produce the correct axis rotation.
Side note: The build up of the network is animated. In fact the connector has to build up along a correct axis. I do it using shape keys.

I propose another approach, trying to simplify your issue.
It uses curves and hook:

How to set it up:

Create a segment (starting from a plane)
Place each extremity to the center of spheres
Turn it to curve AltC
Hook CtrlH each to the corresponding sphere

The hook works like this:

Select the object to hook to
Shift select the object to hook
Enter edit mode
Select the vertex to hook
Hook CtrlH
And choose "to selected object"

After that, depending on your needs, you can turn the curves back to meshes or keep them and animate using "start" or "end" bevel options in the curve properties panel (that can replace the shape key animation you talked about).

I think that the axis are messed up because you didn't apply the transformation rotation to the object.
You can clear the rotation transformation this way:

But, if you don't want any problem at first, you could apply the rotation transformation at the creation of the object:

I hope that it will help you :) .


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Wireframe material node not working in Blender 2.83 or 2.9?
Alright, Im using the wireframe node to mix two Principled shaders in a material. This has worked in the past with eevee and 2.8 - suddenly in 2.83 and 2.9, I just get a black material when I use wireframe node.
Has wireframe been phased out / is there a fix for this?

Wireframe is still working for 2.9. You may have another issue.

Hello, please post a screenshot of your setup so we can evaluate what's wrong


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How to change range of "bake sound to f curves"?
Alright, Im trying to modify the "damp" parameter of a particle system in accordance with the beats of an audio file. So far, I "insert keyframe" on the damp parameter, go to F curves and then select "bake sound to f curves."
My issue is it then only modulates between 0-1. I need the damp to modulate between 0.152 and maybe 0.4.
How can I alter the range of bake sound to f curves in Blender 2.8?

either by scaling and moving the f-curve on the Y axis or using a curve modifier (either Limits or Envelope)

Add an Envelope modifier to the F-curve, and add one control point. Change the min and max values to flatten or raise the amplitude of curves and change Reference value to reposition the central axis of the curves


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Blender audio visualization - waveform line?
Alright, followed all the relevant tutorials on Blender audio visualizations but they all involve either scaling/distorting objects with f curves or the bars type visual like this - https://www.youtube.com/watch?v=fK9Umxy1AAs
What Im trying to achieve is a line waveform like this:

Ive tried applying a cloud distortion to a plane, then slicing it and adding wireframe modifier, but this wasnt the same effect. In Aftereffects, you can increase the number of bars in your audio visualizer and generate this line effect.
Is this possible in Blender?

It is quite possible, but you'll need animation nodes to make it right.

Can you be more specific / provide a tutorial example?

I made this one a while back. https://www.youtube.com/watch?v=JqULEP1o5kA It uses AN to create curves and sound+math to animate them. You can modify the animation to produce the image you're after. It's 3 part, so if you're stuck, consider watching the first ones as well.


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How to smooth out baked sound to f curves?
Ok, I have several scaling animations synced to audio via "Bake sound to f curves" and I've applied an envelope modifier to control the max value the curve can hit. The curve looks like this -

This results in a pretty jumpy animation due to the jagged nature of the line or maybe the easing of the curve itself. Tried changing interpolation mode but this did nothing.
How can I smooth out the animation produced by "bake sound to f curves" ? Is this addon relevant How to change timing of my mocap BVH and how to optimize keyframes ? Or is it in the easing settings?

it's always tricky to do anything with baked curves. check this answer: https://blender.stackexchange.com/questions/19357/smoothing-a-baked-f-curve

@wilks perfect, this works. My only issue is I dont know how to apply my f curve modifiers before I unbake the curve

then i think you need to apply the f-curve modifiers with Bake Curve (Alt+C) then delete the modifiers, then unbake. but might be better to add your modifiers as the last step instead, that would give you more flexibility later

I have two solutions, one requiring an external program.

Smooth the source WAV in Audacity before baking. How to smooth it
will depend on what sounds you're trying to extract. I recommend
narrowing it to a freq range with a combination of high pass and low
pass (or Graphic EQ, put all ranges to 0 except the ones you want,
and maybe give those a bit of a 'curve' with neighbouring
frequencies so you get ramping.
Or you can just un-bake curve in Blender and then press ⎇ Alt  O to smooth.


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Affect curves with wind force field?
I have grass that Ive made individually from tapered curves here, and I want apply a gentle breeze to them. I dont see a way to apply force fields to curves though - you can make the curve itself emit a force field, but not be affected.

Is this possible in Blender?

activate the soft body option in physics option.
it should make the curved bodies affect from the wind forcefield.
convert the curve object to mesh object if u want all the options
Also I would suggest to use some deform modifiers to get the breeze effect instead of going for simulation.


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How to get translucency in parts of skin material?
Alright, Ive watched more complex skin material tutorials for 2.8 but want to know the simplest way to go about this given my skin setup - Ive painted the base material and normals for my skin material in Substance painter and apply them to my model by feeding them into the respective slots in a Principled BDSF.
What I need now is translucency in certain parts of the mesh where human skin is normally translucent, like the ears (here is a successful example):

This requires some sort of painting to delineate where light should shine through and where it shouldn't - so far in my material setup Ive tried a mix shader between the principled BDSF and a Translucent node, as well as checking the 'Subsurface Translucency' box.
I just need to know what kind of map/how I might paint a translucency map and how I can plug it into my material setup to achieve this selective skin translucency?

To achieve the effect you are going for, there are 2 ways to do this, depending on what rendering engine you are using.  I will show you both ways to do it.
Using cycles:
to get translucency in certain parts of your mesh,  all you simply need to do, is turn up your subsurface value in the shader editor.  (see picture below)

after this, the light will shine through only in parts the mesh that are thin enough.  to adjust how much light you want shining through based on how thick/thin your mesh is, you can edit the "subsurface radius" values directly underneath the "subsurface" value on the "principled BSDF" node. (see image below)

After that, it's pretty much done.  You can adjust the other settings to your liking.
Using Eevee:
When using EV to achieve this result.  you do pretty much all the same things that you would do as if you were using cycles (read the above text first if you haven't already) except for one thing.  Make sure you have the desired object selected, then go to the materials tab, and enable: "subsurface translucency".  (see image below)

Once this is done, it should work.  adjust other settings as needed.
And there you have it.  I hope this helped!  :)

Related: Rules and presets for Subsurface Scattering


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Issues with Shadow Mapping?
I'm trying to get a Shadow map for some armor pieces I made and I've been watching this tutorial on how to do it. But some of the options that I need to use to get a good shadow map aren't showing up in my Blender Program. This also includes the Bake tab in Render. Which I need to for the Shadow mapping process. I've done the UV map already but I can't do the shadow map until I know whats wrong.

Are you using cycles? Texture baking is currently only available with blender internal.

This is because you are using Cycles.
Texture baking is currently only supported in Blender internal.
This feature is currently under development, you can see some tests in the bf-cycles mailing list.
Update:
As of Blender 2.71, Cycles now supports texture baking.  To bake a texture:

UV Unwrap the model

Add a blank image texture in the UV/image editor

Add a texture node to your material and select the newly created image

Ensure that the texture node is selected

Press Bake under Properties panel > Render tab > Bake.

Also see:

How do I bake a texture using Cycles bake

Andrew Price's tutorial on cycles baking.


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How to notice edges in each other?
When I notice 2 edges in each other, I select both of the points and hit Alt+M, which allows me to merge them. I always merge them at center to have both points merge and have them as one point. I always, when I finish a model, select every edge in wireframe mode twice to see if there are edges in each other that I may have modeled by mistake. Is there any way the system could help me with this task? It takes a lot of time and I could always miss something. Any help is appreciated. Thank you!

did you try Remove doubles ?

You use W>Remove Doubles, with everything selected A, this will find all the vertices within n units of another vertex and merge them. n is defined by the merge distance, which you can modify using F6 after executing the command.

I never knew this feature existed, thanks!


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Can Cycles nodes use "object coordinates" like blender internal? (or: how can hair-mesh-objects inherit their emitter's texture)?
Basically, I have created a hair systerm, using a mesh object (feathers) instead of strands.
However, my bird (emitter object) is a multicolored image, which I want my feathers to inherit.
In blender internal, this could easily be done by setting the image texture to use "object" coordinates, and I could select my bird-emitter as the object.
However, in cycles, both using nodes (input>texture coordinates>object) and the synonymous procedure in the texture panel, the object coordinate system seems to be dead.
What I mean is, the word "object" is there as an option for a coordinate system, but nowhere can i find a way to select which object's coordinate system I would like!!
First and foremost, I would like to know if there is even a way to use object coordinated in cycles!
Barring that, how might I make my hair particle mesh objects inherit their diffuse color from the surface of their emitter? With strands, the process is automatic. However, with mesh objects, I cannot figure out how to do it!
Thanks for any help!!

You could translate the texture space (Shift T)

I have managed to answer my own specific question, but not the more general question. I will explain, but I hope that someone may be able to answer the general form.
To specifically answer my question, deriving the color of a particle hair MESH from its underlying emitter object (in this case, a feather mesh being colored by the bird's texture) in CYCLES (not Blender Internal), I found resolution in Blender Cookie/Kent Trammel's "Piero" tutorial series (video: body feathers #3), with clarification from a previous Blender developer bug-fix request (found here: https://developer.blender.org/T40712).
To derive a particle mesh's diffuse texture from an underlying emitter in Cycles, in the hair's material nodes, add a Texture Coordinate (add > input ) menu, and then an Image texture, as per normal.
However, the key difference is on the Texture Coordinate tab, you have to click "From Dupli", and as the texture image itself, you must select the texture from the underlying emitter. This info is from Kent Trammel's tutorial.
BUT! There is one more issue that can drive someone crazy. Due to some ambiguity in the underlying code in the past few incarnations of Blender (I am using 2.7), the results of "From Dupli" will NOT show up in a preview render. To see the results, a "real" F12 render must be performed!
So, this is the specific answer to the above question.
However, the general question of "object coordinates" remains open, and that is an issue that goes far beyond particles and emitters, toward texturing objects with other objects, or, for instances, controlling texture placement with an Empty.

For the object/s used as particles you can give them a material and use a particle info node as vector input to an image texture.

While this doesn't just match up with the underlying object material it gives you control of what colour is used for each particle based on its location on the emitter. Projection painting may be an easy way to transfer the colour from one texture to another.

I know this is an old post. I'm sure by now you've figured it out.
I want to make a rug using the Particle System hair and using dupliobj (strands).
I want to have the rug to have a texture on top of it, so the strands have to be colored according to the texture.
Particle System is working, just need to know where and how to apply the texture I want to see the rug have.

!Particle System using Hair and dupliobj]2


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Light field plugin - array of renderings?
I am new to blender and light fields and I used the Blender plugin to create a base grid over my image, a rig and a camera and light source, but I would like to render multiple views of my initial image (like in http://hci.iwr.uni-heidelberg.de/HCI/Research/LightField/images/lumigraphVisualization.png). It might be an easy question, but my lack of experience with Blender doesn't help me much. Also, I am using now a normal static image. Should I be using a 3D mash? Thank you in advance.

Yes you need 3D data for light-field to work.

related: http://blender.stackexchange.com/questions/5034/what-is-lightfield-tools-plugin-for


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How to create keyframes for Animation Nodes, which I can see in dope sheet?
is there a way to create keyframes for Animation Nodes parameters, which are shown in Dope Sheet ?

Unfortunally it is currently a limitation in Blender that keyframes you set on properties of a custom node are not visible in the Dope Sheet.
I suggest you create a controller object in the 3d view that you can animate normally. Than you can use eg the x location of that object to control the procedual animation.
A benefit of this method is that you don't have to have the node editor open to change the value. You can simply move your controller object and see your animation adapting to that.
To get the x location of that object you need the Object Transforms Input and a Separate Vector node.

Not bad workround indeed. :)


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how to create fake reflections on objects?
i am designing a logo for my local esports team.
this is what i have accomplished till now , learning from tutorials and ebooks

and i wanted to make it similar to

this image.
as you can see by comparing the images , i am nowhere near that.
to get the something like a reflection, i UV mapped an image on to the letters it does look better but still looks bad
i want it to look as close as it can .

So when you have created your shape in Illustrator or whatever application you use for SVG.

You create a new scene in Blender, delete the cube and put the render engin to Cycles

After, just import your svg file

You should have your tiny svg file appearing in the scene, select all parts that will have the same material (Shift + B) and join them

Go to your material panel and click on use nodes

To ease the process, change the viewport color to white

We're ready to work on the extrusion and the bevel, so go to the curve panel and play with the settings to have something that suits you.

Now the material part, go to the node editor

And add (Maj + A) a Glossy Shader, a Mix Shader connect everything as the image below

Time to add some light, create 2 planes, that you'll place in order to have good reflections, you'll have to play a little bit with it so the render suits you

The we are going to create the material for the planes, so go back to the node editor and create a Emission shader, set the strength to 15

And last but not least, the glowing corner. Select the part that you didn't join during the first steps, and create a node setup as this one

Set the camera and hit render, you should get something like this:

It is not perfect, but with some tryouts, and a little bit of compositing you should reach a good result.

i will try to add some lighting , and i havent imported the logo via SVG i have modeled it within blender . i want that metal kind of look , thanks for helping

Give me a few minutes, I'm writing down the process, but I think it will be easier for you if you import it in SVG

i imported it with svg and the imported image was for some reason pixelated so the flat sides and edges werent actually flat , it looked bad

Check the update, I'm writing the tutorial

so you used nodes to add the black thing which works like a reflection ... nice,thanks for helping . anyway i can get the black part to tilt?

Actually, with Cycles, the glossy shader acts like a mirror. So you get reflections. :)
Hope it was useful


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CUDA Binary kernel 5.2 error. Fresh Install 2.6
I have never encountered this problem before. Was working in 2.75 and everthing was fine, then I updated to 2.76 (same problem occurs with 2.76b). Now when I try to GPU render in cycles I get this error:
"CUDA binary kernel for this graphics card compute capability (5.2) not found."
I've google some solutions, one being to rename "kernel_sm_50.cubin" to "kernel_sm_52.cubin" in the "scripts/addons/cycles/lib" directory. But when I look in that folder, I only have kernels 20, 21, 30, 35. In the Blender 2.75 install, there is a kernel_sm_50.cubin AND kernel_sm_52.cubin, so I'm a bit confused why these are not showing up in the new install.
Any insight would be helpful, this is the first time I've had a error from a fresh install of a new version. I've updated and reinstalled drivers for my video cards to no effect.
Windows 7
AMD FX 8350
GTX 580
GTX 970
Blender 2.76b

I just downloaded the Zip (Windows 32 bit), and it is missing kernels _50 and _52. Very confusing. I guess I also forgot to mention that I am using the 32bit version of Blender. For whatever reason, the 64bit version always crashes on my 64 bit system, but that is another thread...

The correct kernels (_50 and _52) are in the 64bit zip of 2.76b, but if I try copying those into a 32bit install file path, I get "CUDA error at cuModuleLoad: Invalid kernel image"

There have been issues building cuda kernels on 32 bit (both win and linux) see the history of this build file I expect you will need to use 64bit version to get gpu rendering support. If the 64bit version always crashes then report that as a bug.

Yes, I am running a 64bit version of Windows 7, and honestly haven't been able to get a 64 bit version of Blender to run without crashing since 2.6x.- Something i will report as a bug.


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Copy Rotation Bone Constraint not Smooth
I am struggling to get the CopyRotation bone constraint to work as I expect. Hoping someone can clear up where my confusion is.
I have simplified my issue to this three bone setup:

Bone C is the parent of bone A and bone B.
Bone A has a Copy Rotation
constraint targeting bone B (Y only, LocalWithParent -> LocalWithParent):

(There are also some limit rotation constraints on bones A and C, but I have tested and the issue persists even if they are both removed.)
If I rotate bone B around the local Y, everything works as I expect it to. Bone A acquires the same local Y rotation as bone B, and they face the same direction.
However, if I rotate B freely, allowing local X and Z rotation to occur as well, I experience behavior that I do not expect. Bone A smoothly rotates around local Y as B is rotated (as expected) until hitting certain rotations, where it then seems to "snap" to a different rotation. Here is a video of the issue occurring:
Rotating around local Y causes snapping when X and Z rotations are not 0.
I'm sure this is all a misunderstanding on my part. But I'd be really grateful if someone could help sort me out. In my mind: because I can see that the local Y rotation of bone B changes smoothly as I rotate it (I'm seeing this in the "Transform" view) the Y rotation of bone A should should also change smoothly.
Thanks so much!
The example blend (I don't enough reputation to post this as a real link, sorry): www.filedropper.com/bonerotationsnapexample

If you rotate your bone B around Y and observe its rotation values in XYZ euler, you'll notice all the values change when you expect only the Y axis to change:

This is because the bone was previously rotated from its rest position. The bone rotation is represented always from its rest pose - so what those numbers are is a combined(resulting) rotation of rotating it from the rest pose and then around the Y axis.
So the first problem is that your Y channel doesn't represent the change you rotated around local Y in viewport.
The other problem is that a bone can be rotated only +-180° (with constraints). If you expect to rotate more than this (let's say +190°), the bone rotates actually the opposite shorter way (-170°).
Both these things cause the A bone to rotate the wrong amount and to have a point where it suddenly flips.
The solution is to add bones D and E:

D has Dummy Track targeting tail of B.
E is parented to D and has Copy Rotations from B (world/world).

This way the E bone is only rotated of what the B bone is in Y axis (because the dummy track won't rotate the bone D in Y - it will only rotate in X and Z)
Finally bone A Copies Rotation from E, but Local/Local spaces.
Now if you rotate bone B to a position with only Z or X axes, the bone A will not move. And any Y rotation will be correctly projected onto A.

Wow. I've just tried this out and it works great! Not only that, but thanks to your clear explanation, I "get it". Thanks so much for clearing up my confusion. @Jerryno: you'da'best!


text:
The "register" class function (how to declare)
The documentation on bpy.utils.register_class states:

If the class has a register class method it will be called before registration.

How should this method be declared? What arguments will it be given?

A class method takes at least one argument - the class itself. Here, register (and its counterpart, unregsiter) do not take anything else, so you must declare them this way:
    @classmethod
    def register(cls):
        pass

    @classmethod
    def unregister(cls):
        pass

You have a good example of their usage in Cycles' propertie.py file:
class CyclesRenderSettings(bpy.types.PropertyGroup):
    @classmethod
    def register(cls):
        bpy.types.Scene.cycles = PointerProperty(
                name="Cycles Render Settings",
                description="Cycles render settings",
                type=cls,
                )
        cls.device = EnumProperty(
                name="Device",
                description="Device to use for rendering",
                items=enum_devices,
                default='CPU',
                )
        # ... and so on adding properties to cls

    @classmethod
    def unregister(cls):
        del bpy.types.Scene.cycles

That way, you can embed the definition of your propertygroup and handle its container’s creation and deletion inside the class, instead of having to create/delete bpy.types.Scene.cycles in the global (un)register funcs.

The current version (https://github.com/blender/blender/blob/master/intern/cycles/blender/addon/properties.py) does NOT longer use the second variant (cls.device)


text:
Operator docstrings displayed on buttons, not in search mode
When hovering over an operator button in blender, a nice box pops up that shows at least the docstring of the operator. However, if I find the same operator with the search function (pressing space in 3dview) and hover over it, no popup is shown.
Why is that? Is there a setting to enable this?

Spacebar search uses bpy.types.Menu type class to display content in contrast of bpy.types.Panel for buttons etc.
Drawing methods in both of them will be the same, like:
def draw(self, context):
    self.layout.operator(...)

Menu will have the items with displayed shortcuts aside with no box popup (this is probably because a menu can have a sub-menu as a popup so to not confuse).
Panel formatting has more options and does show the pop-up doc-string.
This is by some design decision and cannot be changed with current exposed api.


text:
Constantly running modal operator
TL;DR: Skip middle paragraph.
I'm trying to make an addon that draws certain info in the view, and have it do that basically all the time that the addon is on.
The way I've been told bgl drawing works is that you put the drawing code in a modal operator. However, all examples I've seen involve starting it from the invoke() method, which is run
when the user executes the operator - not what I want. I've also tried putting the bpy.context.window_manager.modal_handler_add(self) code in the register() class method, but because that method does not have access to self, I only got errors with the various arguments I tried (which were: none, the class (its general name), the cls argument that register(cls) gets, and some others. If needed I'll expand on this).
How do I make the operator run "on startup", or how else can I achieve my goal?

have you tried bpy.app.handlers.load_post.append(load_handler) for running at startup

No, I haven't. What would load_handlerbe in that context?

Ohh, I'm reading the docs right now, handlers might just be awesome!

But hey - couldn't I just use bpy.app.handlers.frame_change_post to draw my stuff and skip the operator altogether?

that would be while the animation playing only

I think @Zeffi has real experience with this

Let us continue this discussion in chat.

It seems impossible to make a modal operator run "on startup", without the user starting it. However, it also seems that the following code adds a drawing function on startup (when the addon is registered) and that that function gets executed indefinitely:
def draw_callback_px():
    #draw whatever you want here, just thought I'd add something

    bgl.glEnable(bgl.GL_BLEND)
    bgl.glColor4f(0.0, 0.0, 0.0, 0.5)
    bgl.glLineWidth(2)

    bgl.glBegin(bgl.GL_LINE_STRIP)

    bgl.glVertex3f(0, 0, 0)
    bgl.glVertex3f(1, 0, 0)
    bgl.glVertex3f(1, 1, 0)
    bgl.glVertex3f(1, 1, 1)

    bgl.glEnd()

    # restore opengl defaults
    bgl.glLineWidth(1)
    bgl.glDisable(bgl.GL_BLEND)
    bgl.glColor4f(0.0, 0.0, 0.0, 1.0)

def register():
    bpy.types.SpaceView3D.draw_handler_add(draw_callback_px, (), 'WINDOW', 'POST_VIEW')

If I now install this addon, the drawing function is appended there both on startup, when installing the addon; even if we're recovering the previous session. At least according to my testing. If someone could test this out to confirm, please do.
...one tiny caveat tho. This does not ever tag the drawing area for redrawing, so to see the drawings, one sometimes has to interact with the 3Dview are at least once after installing the addon.

maybe adding bpy.ops.wm.redraw_timer(type='DRAW_WIN_SWAP', iterations=1) to force redraw will solve the "caveat"

Well yeah this will be good for static drawing, I've done this also, but couldn't access events, thus mouse coords, which I need for interactivity:(

Yeah, sadly, that's the case.

hi, just came across this question, thanks for this ! i was searching for a way to add static draw through python ! but i'm stucked with the unregistering of this handler... it can't pass a handle, like other draw handler. I'm no coder, just enthusiastic and don't have a clue, do you have any idea ? :) thank you very much !

I am afraid this is a limitation and you cannot interactively draw with bgl outside of modal operator. There is no way to initialize the drawing handler because it needs the modal operator for access to events and the modal loop where tag redraw would happen.
Tag redraw could be done but the events are the bummer. Linking similar: Get events without running modal
From blender api user events outside of modal can't be caught. There is probably a possibility to catch them with python in monitor space and from blender areas and window positions get them local (like mouse coords).
From user perspective how blender is made it seems the philosophy is that user should have control over modal operators and start/end them manually ideally with button in ui. So something doesn't run in the background without your knowledge. There is somewhere an answer from Brecht on something similar but couln't find it.
There is possibility to call an operator from handlers, but mostly you will get another limitation:
 "RuntimeError: maximum recursion depth exceeded"

Calling the operator from load_pre handler should be fine though. See similar: My custom timer is cancelled when loading a *.blend file

Yes, I am beginning to see that this might border on the impossible. However, load_pre is not good either because, from what I know, it only runs wneh I'm opening a new file. Or am I wrong?

@Ludwik you are correct, what we need is to monitor whether the modal operator is running or not in the scene_update_pre handler and call it if its not running. This however gives the runtime error :( .. I once came across same issue when trying to display a code minimap in text editor that would display automatically.

Wrong!
I actually just found a way to draw outside a modal operator. Will add my own answer soon. Nevertheless, thanks ;)

@Ludwik If you did your will be a hero and I would thank you billion times!


text:
How to access new attribute types in render
It appears we can create arbitrary new attributes in blender 2.9:
https://docs.blender.org/api/current/bpy.types.Attribute.html
This is a great new feature, but I can't figure out how to access these attributes in a render.  For instance, if I create a new 'VERTEX' attribute of type 'FLOAT_VECTOR' and assign some colour values to it, and then reference that attribute in an attribute node and pipe it into the base colour of a shader, I just get black.
Has anyone figured this out?  Is it maybe simply not implemented yet?

https://docs.blender.org/manual/en/dev/render/layers/passes_aov.html https://docs.blender.org/manual/en/dev/render/shader_nodes/output/aov.html https://docs.blender.org/manual/en/dev/render/layers/passes.html

Thanks for that, Duarte, good to know about AOVs in cycles, didn't know that was a thing!  But my question is about the new attributes in 2.9, and how to make them visible to the renderer.


text:
Retrieve uv coordinate at hit point of OSL trace() call
Using getmessage("trace",...) I can get the name of the geometry, it's location, the position of the hit, etc, but it doesn't appear that I can obtain the uv coordinate for a uv map of the hit geometry.
To be clear, I don't mean the uv parameter for the triangle that I hit, but the texture coordinate from a uv map.
Has anyone figured out a way to do this?

Did you try geom:uv?  Moreover, to increase chance of getting answer, providing .blend file may help.

Hi there @cppBeginner, I tried everything plausible.  In the end I looked through the source code and convinced myself that it wasn't actually supported by the current code.  In any case, as nice as it would be to have this as a feature, I figured out another way to solve the problem.

It sounds similar to traceset which is not supported yet.   How did you solve?  I am curious.

According to https://docs.blender.org/manual/en/2.79/render/cycles/nodes/osl.html, the geom:uv should work.  If it is not, it would be nice to be reported via https://developer.blender.org/maniphest/task/edit/form/1/.  From my experience, the developers use several days to react, but every report will be read.


text:
Custom vertex attributes?
I would like to define a vector-valued custom attribute at each mesh vertex.  I would like to define a vector direction at each vertex, and use the interpolated value across the face for anisotropic shading.
It seems I can't store the value in a vertex color, since they are [0,1] values (and are possibly represented with 0-255 values...?).
What I'm really looking for is a blender equivalent to a primvar, but it doesn't seem to exist.  My current intended workaround is to store the vector in two uv maps, but that is awfully hacky.
If I'm reading this correctly, cycles supports this, but blender does not?
Are there any standard workarounds for this?

A little bit late to answer. I don't know about the older version, but in blender 3.1 you can define Custom Attributes when you go to Object Data Properties. There you can choose Domain and Data Type of your custom attribute. You can then e.g. assign these custom attributes using Python API.


text:
How can I export an FBX with Textures
I cannot seem to get my model to export as an FBX with the textures intact. Is there a tutorial that shows how to do this?
Thanks!

What render engine are you using?

For which application? — Helvetica

I think this would only work if you have textures added to Blender Internal Materials.  You should provide more information.  You can upload a .blend file to PasteAll.org and paste the link here.  You should definitely remove the tutorial request from your question, you're question is likely to be closed because of that.

I am wanting to export an FBX from Blender for use within Unreal Engine 4. However, I cannot figure out how to do this. I am able to export the model, but it has no texture information. This leaves me having to re-apply all of the materials one-by-one. Thanks!


text:
Blender to Unity, Animations are exporting 2x
My animations are exporting under (armature | animation-name) and (animation-name). This goes for each animation I made so it takes double the space. Is there any way to export them from blender to unity only once?

Okay so the only way I know of doing this is putting al of your animations in the NLA window. Like so.

After that you can export the Armature + Model.
Deselect - All actions
Select - NLA Strips ( in which you put the animations )

That way, when you import it into unity you will only get the animations that were pushed down on the NLA strip.


text:
Material nodes - make a range of values?
Ok, Im trying to fake volumetric light shafts using this node setup and a gradient texture made in photoshop:

Basically this still looks not great, and I want to have a "gradient" of the emission strength, emanating out from the bottom. It's almost as if I need to convert the black/white of the gradient to a value? How could I do this? Currently:

Blender has a built in gradient texture that you should be able to map exactly like you have the image texture now. That will allow you some more control I would think. You may want to look into the colorramp node as well, as that will also help you control the gradients.

That said, I would suggest using faked volumetrics if you want a nice light beam, such as in this tutorial here: https://cloud.blender.org/p/caminandes-3/56c6da5cc379cf0079716873. It's still really fast, and will help avoid a bunch of issues that can arise when using surface emissions (being able to see through parts of the object, or needing a denser mesh for example).

I created a short tutorial video a while ago that may help with using and controlling ColorRamp and Gradients to make volumetic type effects.  https://www.youtube.com/watch?time_continue=1&v=cPvYAHc9vCE


text:
Create this procedural animation with a script?
Ok, Im making trees using the skin modifier, which has the option to automatically make armatures along the curve when done extruding.
(each of the lines turns into a bone)

I want to animate these trees growing, so each bone has to scale from 0 to 1 one after the other. This is tedious, and wondering if there's a way to make this animation via script?

Recommend breaking this down. Creating the armature using the skin modifier in edit mode and animating I would consider as two separate steps.  I imagine you model a fully grown tree and then grow it, as opposed to starting from a zero tree.  Please consider the answer-er here. ,, be far less tedious not having to create the model.  Post a sample file. Most of the time doing something in the UI can be done in a scrpt. Are the bone names in some order ... Are vertex groups assigned.  There is a chasm between the long answer and the short answer. The short: yes there is a way.

@batFINGER sorry. worded question poorly - 1. the bones are named sequentially and 2. I have already made the tree with armature attached to each segment. I am asking purely about scripting for the ANIMATION of these bones


text:
Import/export JSON add-on in 2.8?
Ok there are multiple JSON addons for 2.79 and they work, but I need an add-on for 2.8. Are there any currently for import/export JSON?

Im not sure if this will help but try this
https://github.com/supermedium/aframe-particleplayer-component


text:
Particles won't collide with object?
I have a particle system in 2.8 that emits metaballs, and Ive added Collision to the object I want to collide with. Settings on the collision have friction at 1.
Ive followed tutorials, however my metaballs pass right thru the collision object -
Can metaballs not collide? Whats wrong here?

test this using spheres or something.  If that produces the same result, it's not the metaballs.  Then try replacing the collision object with a simple mesh.

@RBlong2us no, even spheres dont collide with a simple plane.

how about changing the collision object?

Maybe this helps: https://blenderartists.org/t/collision-with-metaballs/1154033/2

I tried using a particle system with metaballs, and the collided just fine.  do you have any other modifiers on your collision object?

on the particles object, in the particles panel, in physics, and under deflection, do you have a collection selected under collision selected?(if you do and your colliding object isn't under that collection, it won't work)


text:
Why is half of mesh transparent in edit mode?
So this mesh (downloaded) looks like this in object mode -

Then in edit mode looks like only some of the faces actually exist-

There's no modifiers on the object. What is this?

move the mirror modifier on the top

@atek what do you mean? It doesn't have mirror modifier, and it doesn't need to be mirrored exactly. Something is weird in edit mode

could you please share just this part?

Alt+H to unhide faces maybe?

move the order of the mirror modifier on the top and rest or play with the modifier order

@atek dude there is no mirror modifier

@Merlin that was it, thank you!

Parts of the mesh are hidden.
You can unhide the using either:
Alt + H hotkey
Or from the menu in edit mode:
Mesh -> Show/Hide -> Reveal Hidden


text:
How to make a disintegrating meteor?
Ok what Ive done so far to make a meteor is this - just a ball at the front of a particle system contained in a weird shape -

Tried using density vertex groups to clump more particles near the comet head but this looked too clumped. Also, I need to have the head be breaking apart slightly -

How can I do this properly/with animation?


text:
How to render an animation as video in Blender?
Yesterday I was working on a simple animation, an animated logo.
Here is an image of the progress:

I already have the animation working and everything is okay with the project, but I can't figure out how I can render the animation and turn it into an AVI format video.
How do I render an animation in Blender?

Yeah but when l click on the animation and when it's finnished l can only save as an image only can't find a way how to save as a video

Scrool down that tab, until you find "Output" and then select a video format where it says png, or look at this video for converting stills into an animation : http://vimeo.com/26366908

Related: http://blender.stackexchange.com/q/3470/599

@someonewithpc When I started with Blender I had no idea what rendering even meant, let alone how to save renders.

You have created an animation and want to make it into a final video format. Here are the steps -

Choose an output location for your animation under the Output Settings tab by clicking on "Output".

Set the Path to the folder where you want your output files to be saved, whether it is rendered as image files or a video file.

Before you make a video file of your animation, it is a good idea to render it as an Image Sequence first. If you render it directly to a video file, you can't stop/pause the render or there is a chance that you will get a corrupted file and have to render all of the frames all over again. Having an image sequence will allow you to experiment with different formats for and settings for encoding to video.
(If you want to render directly to video without saving as images, skip to step 8)

When you have chosen an output directory for your Image Sequence, choose an Image Format.

On the main menu Select Render > Render Animation (or press the shortcut Ctrl + F12)

Blender will now start rendering the scene frames one by one.

When the rendering is finished you will have a lot of numbered images. To encode them as a single video file, start a new project and choose New > Video Editing.

On the Sequencer window, click on Add > Image Sequence

Select all of the image files of your animation with A and click on "Add image strip".

In the Properties Window now select FFmpeg video as File format.

A new tab will appear with Encoding options.
There you can select the Container and the Codec for the output video file.
Container is the file format for the file, (Mov, Avi, Ogg, MP4, to name a few) sometimes is referred as a "wrapper".
Codec (short for Compression-Decompression) Is how the image is compressed. The picture quality, file size and processing power needed to view the file are largely determined by the kind of codec used and the settings used for it.

On the main menu Select Render > Render Animation (or press the shortcut Ctrl + F12)

The result of this will be a video file.
----------
For older versions of blender (previous to 2.79)
The options to choose formats are like this:

Choose a video format for your animation here:

The Render Animation" is located in "Render" tab.
To open the video editor click on "Choose screen layout" and then "Video Editing".

Check this Meta post http://meta.blender.stackexchange.com/questions/436/what-to-do-with-questions-which-have-been-answered-in-comments ; Your answer is purely based on my comments above...

No problem, if I wanted to I could have answered it...

I didn't noticed the link for the video. How can I delete my answer (if it doesn't serve any purpose)? No "delete" button.

@Laira It does serve a purpose, question should be answered in the answer section, not on comments; Leave your answer there

Okay thank you all for the great help l already saved the Logo animation as a AVI video and l hope this question wasn't too weird and again thank you all

@Paulius If this answer has satisfactorily answered your question, consider marking it as accepted by clicking the checkmark next to it :)

under Step 2, I haven't yet found "the output settings." I don't see them in the "User Preferences," or under the "Render" menu ... still looking.

For 2.81 beta, what does this process look like now? I can't find the menu for PNG/JPG from Animation in Preferences at all.

How do I do this in 2.81?  There is no such "Render" tab by clicking on "Output".

Remember: If you want audio in your video, select an audio codec like Vorbis with 128k bitrate for example, instead of leaving it as "No Audio".

I found you don't have to use the video editor. If you set the output, it saves the file as it renders, that way you can use a video editor you are already familiar with.

How would I add audio? This audio belongs to a MPEG video file though.
Let me know if I should start a new question.

He is saying if you are only use blender for the first step and want to add things like audio in another video editor. If you want to know how to add video search for that question or make a new one.


text:
What is the best way to get image from vertex group?
I have a UV unwrapped plane and some faces assigned in Vertex Group. What is the best way to get an image from this data? Maybe a  bLack and white image, it would best  if it could be scripted in the bpy

Not entirely sure if I understand you correctly. Do you mean exporting the UV layout into an image?

Can you give a concrete example? what will this data be used for?

you can assign vertex colors to the vertex group and then bake it as a texture

I'm too lazy to write it all out but you can see the process of doing it manually here: https://www.youtube.com/watch?v=SsilkGVy_dQ The only issue in automating it would be getting the x and y size of the image required if you want to make it as wide in pixels as it's wide in polygons. But that shouldn't be an issue if the plane is automatically generated too

Check out bpy.ops.uv.export_layout.

Btw: If you need black and white output for export_layout set opacity to 1. Afterwards you could use ImageMagick: convert exported.png -channel alpha -threshold 50% -white-threshold 0 -alpha Off png:- | convert - -morphology Close:1 Diamond final.png


text:
Inserting frames into time line
I want to insert 20 frames into the beginning of the animation so that I can make adjustments. Is there anyway to do this or do I need to shift every object that I have animated over 20 frames? Thanks!
On the time line there appears to be negative frames but I can't access those is there anyway I could start my animation at the -20th frame? That would solve my problem

Go into the Dope Sheet and select all your keyframes (A), then move them 20 frames (G20).
The Dope Sheet:

If you found this answered your question, please mark it a accepted.

Well.. I can't find this on the wiki, but can Ctrl+LMB to one side of the current frame (green line) to select all frames on that side and deselect all on the opposite side.
The current frame green line is in fact a pivot.

Also maybe deactivate the small arrow like button that limits dope sheet to selected objects. And possibly activate the "show hidden" button next to it.

This works very well when all elements are visible, but some may come into play at a later stage in the timeline, so better push the little ghost-button at the bottom to make them all visible. Else you'll mess up the time line, as I've discovered :-). Can be fixed quite easy, but better prevent that.


text:
Duplicating motionpaths(keyframes)
I am kind of new to this whole blender program, and I'm currently trying to make a text animation where the letters are made out metaballs.

By now I have made 850 metaballs and I'm not even done with a single letter, I was wondering if there was any way to copy the or duplicate the metaballs and in some way make my work easier?
The way I'm doing is most likely the slowest.


text:
How to achieve fire effect like this?
I'm in eevee 2.8 and trying to emulate this:  Fire Gif
He explains how he does this with billboards, but I'm wondering this is the best approach in blender.
Is this (the fire and smoke) possible with metaballs? Or some kind of billboarding and dynamic material?

Do you just want to make a fire, or do you also want the strange 2d pattern coming off of the top like his?

@person132 Both yes - fire and smoke


text:
Eevee avoid light reflections in glass, but only one object?
Im using an area light in Blender, and it is reflecting in the glass of a certain object. Reading other answers, I tried turning specular to zero. Problem is this means it doesn't reflect off anything glossy either - I really only need to "exclude" reflections on 1 glass object.
How can I do this in Blender 2.8 eevee?


text:
Make eevee shadows darker?
Ok I’m trying to get darker, noticeable shadows in eevee, yet I’m barely getting anything, even with contact shadows on:

What can I change?

Please don't take photos of your display, those are very hard to read especially when picture quality is critical to solve the issue

https://www.take-a-screenshot.org should help with taking clearer screenshots.

You can actually darken the shadow using a light path node.With or without HDRI lights..
You can adjust the darkness by increasing or decreasing the brightness value.... I don't know is there any better way to do this,but this will do the job!

That is brilliant, thank you! I did not even know one could boost the shadow pass that way. In my case though, I wish there was a way to increase the darkness of a shadow from a cutout image without increasing ALL the shadows in the image. In Cycles, placing a cutout will cast a proper dark shadow from a sun lamp, but in Eevee, the shadow gets washed out by the HDRI lighting. It's like shadows are NOT additive in Eevee, you can't add one shadow on another to make it darker, it just seems that all shadows add up to 1, which is unfortunate.

I ended up using the technique described at the thread below to render my main scene, plus a 2nd scene with a shadow pass and then composite in a third scene with a multiply node for the shadow. This was necessary because I was using a shadow catcher in Eevee and I did not want the cutout shadows getting darker on the ground, nor did I want dark shadows everywhere, only on a few objects. In a more basic setup, one could simply run a shadow pass in their current scene layer and Multiply that shadow pass in the compositor to get a darker shadow. https://blender.stackexchange.com/q/150009/39431


text:
Why is there so much more hair in render than viewport?
Ok Ive checked relevant settings and made sure under "display" in my hair particle settings, it is 100%. I dont know why, in latest 2.8, there is so much more hair in render vs viewport - for example the hair looks normal in viewport, then in (cycles) render I get -

Here are other settings:

Is it to do with hair dynamics? even with that off, I still get this increase in hair.

Check that Subsurf levels for viewport and render are equal. Also check other modifiers - they must have same setup for render and viewport

Apart from the children display and render amount, there is another Amount option under the Viewport Display panel. You might have set it low. So at render time its rendering 100% of the hair particles.


text:
How to make particles a different color depending on which side they’re on?
Ok I have a particle system (in 2.8) where the object emitted is a meatball. I need to have the left side of the emitter emit red metaballs and the right side blue, with blending in the middle. I probably need to use a colorramp here, but don’t know what the exact node setup would be.
Here’s a diagram of what I need where R is red side and B is blue

How can I do this?

i dont know if this works cuz im not home right now but you could try it with dynamic paint

The color ramp factor can be based on the velocity info of the particle system. Or you can use "Object info" >> "Location" or "Geometry" >> "Position" as an input, but those are based on the world coordinates, so they will work only in the Origo.

May be you will have to use some math nodes before the color ramp for fine tuning.

Objective -
An emitter spews out spheres that start out dark grey and when passing boundaries at the left and right, change colour as they cross the boundaries.

The job is fairly straight forward because Blender's particle system reproduces the same particle pattern and animation each time.  It means you can render out three separate videos and the particles in all three will move identically.
Use a mask in front of the camera (or do it with masking nodes) that's divided vertically into 3 segments.  One each for left & right segments and one for the center.
Remove one face at a time and set the the emitter object's colour, (sphere) to whatever you like.
Render that with a transparent background. (alplha layered)
Replace the first face, remove the next and change the sphere color. Render that out with a transparent background also.  (png with RGBA active?)
Do the same a third time with the last face removed.
Mix all three in the VSE using "Alpha Over" in each strip's properties, and add a suitable background on the very bottom strip.
/////////////////////////////


text:
Metaballs show in rendered viewport but not in actual render?
I have a particle system that emits metaballs in Blender 2.8 eevee. My settings:

They don't show up in the render - not the object itself nor the metaballs emitted. In the rendered view they show up:

But in render, nothing:

Why?

Is viewport visibility on and render vis off? I don't have an issue rendering metaballs with current master, your copy of 2.80 is looking a bit old.

You probably solved this by now but in case anyone is wondering - I had the same issue with emitting metaballs showing up fine in the viewport but not rendering. In my case the emitter object had rigid body physics enabled. Once I disabled that the problem was solved and metaballs rendered fine


text:
How to select the entire object on edit mode
I need to have further explanations about how to select everything while I'm on edit mode as in this tutorial.
I would like to know how I can select the entire object in edit mode because when I'm on object mode I can select only one part of the object and when I switch to edit mode I can again edit only the part that I have previously selected on object mode. I've tried to do CTRL+G but at the minute 28.11 I saw that it's not the right answer,because she can select each individual piece of the character,but I can't. So,what's the solution ? thanks.

Press [A] to select every face; And [Ctrl] + [J] to join all selected objects.

Please include all information needed in the question, referencing a tutorial means in the future, the question may be incomplete if the link breaks.

You hit Ctrl-J to join all your objects (they need to be selected). When in Edit Mode hit the A key to select all your points (vertices). You can hit it again to deselect everything. If you want to only select your object, use L.

I've already tried but I think that's not the solution of the problem. Infact,go to minute 28.11 and tell me how can I select only the head if previously I have joined everything...

[L] for linked faces/edges.

You can in edit mode, you are selecting the vertices. I can see that she has joined to object. You can select separate groups of vertices in edit mode by hovering and hitting L

@Marietto If my post helped you, please hit the check mark button below the voting buttons on the right side of this post. Thanks, it was a pleasure helping you.

I tried to join objects that are several parts of a map (extracted from Spyro 2 game with SpyroEdit / Genesis tools) but it looks like it breaks UV mapping. Isn't there a workaround?

Use CtrlJ to join two or more objects together and press A to select the whole mesh. You can also use B to select like half of the mesh or do the same for the whole mesh.

You can select multiple objets (=parts) in object mode and enter edit mode for all of them at once.
Then you can naturally press A to select all the geometry. Exit edit mode to change which objets (=parts) are selectable/editable in edit mode.
Be careful of your wording: 'Object' refers to something very specific in blender. Perhaps 'model' is more appropriate.


text:
How do I crop everything in Video Editor?
I have made a video composed of several videos with transitions etc, but they all have a 80px black strip on the top and bottom, and I'd like to remove it (so that the video's height is 160px less). How do I crop the video?

You can group your clips in to a meta strip by selecting them and hitting Ctrl G. If you want to edit the clips inside it after grouping them, select your meta strip and hit Tab.
You can now apply an Image Crop to the meta strip in the properties panel (N). Be sure to check Image Offset. You will also need to change the render dimensions to the correct size.
Screenshot:

You can avoid the need to crop in the video sequence editor entirely by performing the crop in the render dimensions. Simply set the dimensions to the target aspect ratio for you image.

Cropping the render dimensions sounds like the easiest way to do it, but if I change the Y value to 160 less (in the Properties > Render Presets > Resolution), the video gets squished. I don't seem to know how to change the aspect ratio values to get the desired result. If the video is 1200 x 960 and I want it to be 1200 x 800 (with 160 cut off), how would I set the aspect ratio (currently 1:1!) and resolution?

Because no matter how I set the values (and check the Crop and Border checkboxes), nothing ever gets cut off, just rescaled inside the new dimensions.

Just go to Properties > Render Presets > Resolution and set your preferred resolution. Keep the Aspect Ratio to 1:1. Then go to the Video Sequence Editor properties panel.
Unchecked the Image Crop and Check the Image Offset change the value of X and Y to your own offset.


text:
Rigify extreme deformations
I've seen many rigify questions on this site, but none that explain something to this extreme. This model is freshly rigged with rigify. Any minor change in pose causes a large deformation, and nothing is consistent from any video or tutorial I have been following.

I understand weight paint, but it only seems to make the problem worse by introducing new ones.
To the blend file
Thank you for your help, and I hope something can be done about it. There is another model suffering from the same problems.

It IS the weight painting.

@Laina Also, Copyrights...

@someonewithpc I know where it's from, and I never claimed it was mine. It's a solid model for practice.

@Laina I just want to make sure you realize it's copyrighted, and you might (not really gonna happen)  get in problems.

@someonewithpc I do appreciate the concern. Thank you! And too many take advantage of material that isn't theirs so I would say the same thing you did. Wanted to use a good control model to experiment with to try to solve some problems.


text:
Manual voice syncing?
I wan't to animate based on an audio track by manually using key frames and shape keys. In the past I have used audio scrubbing. I would place my sound clip into the VSE and it would work perfectly.
But now, suddenly for a reason unknown to me it has stopped working as usual. Instead of just playing the sound for that frame, it plays the whole track whenever I click on the timeline.
How can I revert it to its old behavior?

I don't really understand the problems you have since last december. I also tried to create animations from a control-file therefore I share some thoughts on this topic.
Pointers

First step would be to identifiy the phonems in the audio stream used there is lip-syncing tool Papagayo
In this BA thread someone used the Papagayo output as input for the script posted there, I it basically applies poses from a poselib.
I was able to get it work for the latetest blender release.

Answer

My question is if anyone knows how i could animate to a voice without
  automating it with the idea of shape keys for certain voice sounds.

I created a script to read a control file with frame#, object and influence to automatically create an animation: Mapping an algorithm to an animation
It is very basic but easy to extend to use multiple shape-keys.


text:
modeling a building from one cube
I wanted to build a building like the picture and what I did was putting two cubes on top of each other . I want know how this can be made from one cube I mean start from one cube and extrude or ...

Enter edit mode
Hit Ctrl-R to make a loop cut across the mesh.
Repeat in other direction
Select face and extrude it upwards(E-Z)

how do you make these videos?

@pluke You can use either licecap (@gandalf3's suggestion) or gifcam cegton's suggestion. I used keypose for the shortcuts.

In Edit Mode select the upper face and snap the cursor to it (press Shift+S-->Cursor to Selected).

Press E to extrude and then S to scale the extrusion. Confirm the operation with Enter.

Extrude once more along z axis. Press E, then Z and confirm the transformation.

Now select the whole extruded element and place it wherever you like, using G and choosing the axis you like.

And here it is.

you can also extrude faces like that using inset. select the face(s) and "i", then move mouse to change size.

If you do not want to mess with the topology of the lower part of the building, you can build them separately, select both, and join them with Ctrl+J.

Another option is to select the top face and duplicated it with Shift+D.

You will then be able to edit the different parts with complete flexibility, with no fear of ruining your work on the other parts of the building.


text:
Way to keep lighting from lamps without influence from environmental textures
I did a nice little motion track:
Motion Tracked
I want to apply a glossy material with a little bit of roughness to give it a metallic look, and in the reflection of the metal, I want to see the surrounding environment.  I plan on using a still image from the original footage and applying it as an environmental texture (in Cycles).  Is there any way to make it so the environmental texture only influences the reflection, and has  no influence on the lighting?  If so, please explain to me how this can be accomplished.  Thanks!

If you only want reflections from an object or world texture, deactivate everything but glossy in object's or world's ray visibility :

He is using it for motion tracking, if he is using a mixture of Diffuse and Glossy he should absolutely use the Diffuse setting, transmission and volume scatter are less necessary. Using the world settings might work for him, but for more complex projects I'd recommend not messing with them. World settings should not be fiddled with if it can be helped, it is better to keep things localized.

i agree, but this is the simple and easy version, good for testing, understanding and basic setup. The world is an exemple. I didn't think it was necessary to add a screenshot with an object as the principle is the same.

Not that I know of, however you can add a sphere, add the texture to it using a Diffuse material, and then disable the Shadows option.
Add a UV Sphere to your scene (Shift+A), and scale as desired (S).
Now go into edit mode (Tab) and select all (A) and unwrap using sphere projection (U > Sphere Projection)

Now set up your material like this:

Now all you need to do is to disable the casting of shadows. Go to Object > Ray Visibility and disable the Shadow option and the Camera option.

If the reflections are not quite apparent enough you can try setting the material of the sphere to an Emission shader instead of Diffuse and tweaking the value.
Here are my results:
Diffuse

Glossy

Thank you for your detailed response.  I enjoy the convenience that having a Blender Stack Exchange website brings, and thank you for your input.

No problem, glad to help


text:
Loading ASC files in blender
I need to import an ASC, which is a Digital Terrain Model, file into blender. Basically it's a matrix of points, each represented by a number corrisponding to his height. What's the best way to do that? Is there anything you know that it's pre build or I have to write my own loader in Phyton?
Thanks

I think your best bet would be to convert asc to something standardized like obj first.

And how can I do that? Do you know?

The ESRI ASCII grid format seems to be pretty straight forward (see http://en.wikipedia.org/wiki/Esri_grid). If you do not have a converter for other formats, I think writing your own python code is your best option.

It's exactly that format, thanks. I'll look for a converter

@BelottiGhilardi did you find anything yet ?

I think I'll use a grid and via Phyton (if that's even possible) I'll elevate the points reading them from the files. I hope you understand what I mean, beacuse I'm new to Blender and I'm not so familiar with the jargon

for one of my project i was using this addon: https://sourceforge.net/projects/pointcloudskin/files/latest/download?source=files
it did its job very well - just had to make sure the ASCII data is correct (x,y,z)
I am not sure if its compatible with 2.76a - but once you manage to import the data and skin the point cloud - you can always go for newer blender version.
He has also a CSV import addon - which also comes very handy in this matters.
As for the skinning process: it a bit of try and error process.
good luck

http://blenderartists.org/forum/showthread.php?241950-A-Script-to-Skin-a-Point-Cloud-(for-Blender-2-6x-or-Later)&highlight=point+cloud+import

Last year I wrote a simple importer for ASC files (see: this blenderartists thread http://blenderartists.org/forum/archive/index.php/t-357605.html )
https://gist.github.com/zeffii/54d65b86a460605c3d15
code:
import bpy
import time
import csv

A = time.time()

dfile = r"C:\Users\dealga\Desktop\Archive\SU8606_DSM_1M.asc"

getval = lambda i: int(next(i).split()[1])

with open(dfile) as ofile:
    ncols = getval(ofile)
    nrows = getval(ofile)
    xllcorner = getval(ofile)
    yllcorner = getval(ofile)
    cellsize = getval(ofile)
    NODATA_value = getval(ofile)

    print(ncols, nrows, xllcorner, yllcorner, cellsize, NODATA_value)

    # this will read the rest
    verts = []
    add_vert = verts.append
    asc_reader = csv.reader(ofile, delimiter=' ')

    # ni = nrows #? +1 -1
    # nj = ncols #? +1 -1
    ni = 1000
    nj = 1000

    for i, row in enumerate(asc_reader):
        if i >= ni:
            break
        for j in range(int(ncols)):
            if j >= nj:
                break
            z = (float(row[j]) / 60)
            x = j * 0.01   #   cell x width
            y = i * 0.01   #   cell y width
            add_vert((x,y,z))

    print('done')
    print('last vertex:', verts[-1])

B = time.time()

total_time = B-A
print('total_time:', total_time)

faces = []
add_face = faces.append

# generate_edges, i = verts y, j = verts x
total_range = ((ni-1) * (nj))
indices = []
for i in range(total_range):
    if not ((i+1) % nj == 0):
        add_face([i, i+nj, i+nj+1, i+1])

# do your own error handling
mesh_data = bpy.data.meshes.new("LIDAR_mesh_data3")
mesh_data.from_pydata(verts, [], faces)
mesh_data.update()

LIDAR_object = bpy.data.objects.new("LIDAR_Object3", mesh_data)

scene = bpy.context.scene
scene.objects.link(LIDAR_object)
LIDAR_object.select = True

I also needed to import an ASC file into Blender. I found that the open source program MeshLab could import ASC files and then export it to an OBJ file, which I could import in Blender. Pretty easy actually.


text:
How to place image in a surface

hi guys, I'm a newbie in blender and I just want to ask how to map and image/graffiti in surfaces that already has texture in it where there is X MARK (see image attached)I have my node setup also attached. I tried the uv maps(below the vertex group) but I dont know how it works,I also tried overlaying using mixRGB node but it maps to every surface that has concrete.I cant control it

Watch this tutorial https://www.youtube.com/watch?v=vISEwqNHqe4

Could you post a .blend file?

thank you for the respond. im sorry.my question wasnt clear, its a 3drender image, i wasnt planning for animation yet.

my blend file is 127mb,but ill make a more simple version,i'll post it after its done.

@Allen 127mb is not a problem at all! Be sure to pack your images.

im from the philippines and the internet connection here is super slow.at least here in my place, so 127 mb would take too long, however i posted a simpler version though.

A mix RGB node will work fine:

Use the alpha from the image on top for the fac input. You may need to try reversing which image is on top for best results.

http://www.4shared.com/rar/mBOMonCdce/test.html here i have a test version, i used the  color and the alpha and it seem working  because i have one side  with one circles .but the other side has circles map into them as well

another thing this is that. when i scale the side with one circle i ended up scaling the cobblestone texture too, instead of just scaling the circle

@Allen I can't download from that site, try here: http://www.pasteall.org/blend/ Free, no account :D

@Allen You need to have different mapping nodes for each of them.

oh sorry :)
http://www.pasteall.org/blend/34435
http://www.pasteall.org/pic/83922

The blend appears to be corrupted, I keep getting odd dialogs. Have you tried using the nodes in the example?

corrupted?should i upload the .blend1 file,maybe because i havent pack the 2 other images used.any way you could just replace it, right?,
yes i tried the nodes method you showed me but the image are mapping all over the, i just want to be on one plain
http://www.pasteall.org/pic/83923

http://www.pasteall.org/blend/34436 here i packed them,

The blend seems to work perfectly? What is the issue?

yes but, the circles shows in every pplain that has concrete texture, i just want the circle to be on the left side

@Allen You have to stop it from reapeating: http://stackoverflow.com/questions/19110019/stop-image-texture-from-stretching-blender


text:
How to Model a Mushroom shape?
Is there any good way to make a half decent mushroom?
I'm specifically trying to make the mushroom on the back of Parasect for an animation. How can you make a rounded cone? Is there an addon for that, or do I have to make it myself?
Specifically, I'm thinking of a cross between an ovoid three-dimensional shape and a cone.
(It's also a good question when you are making rounded nose cones for objecs such as rockets)

If you feel the need to say "please don't delete" - maybe you should have chosen a better title

Sounds like too broad. What exactly your problem consists in?

Sheesh people, I'm struggling to keep reputation up here! I'm also trying to make a rounded tip on a cone, and really have no idea how to do it except to bind a sphere to a cone and that's not exactly what I want.

and what's with Workflow?

related: (screw modifier) http://blender.stackexchange.com/questions/24506/using-the-screw-modifier-how-do-i-accurately-set-the-axis-of-rotation

possible duplicate (not question, but answer) http://blender.stackexchange.com/questions/28976/how-to-model-the-rounded-outline-of-a-column

oh my gosh guys, thank you so much for the overwhelming positive community response! If only I could see who upvoted things...

If a Screw Modifier isn't already enough, simple Polygon modelling will be surely.

add a 5 (or more..) sided circle
extrude up and scale to give hints of the shape
then stick a subsurf modifier on it
(optional) then use a lattice or a curve modifier for deformation. Deform to taste.

The lattice:

The Curve Modifier:

Wow! Thanks a lot, that pretty much wraps up the question!

Is there a particular reason you went with a 5 sided circle?

For all things round I use 5 or more edges/verts for a profile, helps guide the subsurface modifier to produce truly round shapes. 5 is not entirely arbitrary, more could be used, but I like to let the subsurf modifier take care of that

The lattice isn't really needed for the prop

deform to taste, mushrooms are never perfect, a bit of "noise" or deformation can help give them character :)

Nowadays, I'd use 12 for the circle verticles; no latex nor curve (simply using proportional editing). Anyway, your suggestion is still valid and produces a good looking result. Chapeau.


text:
Is there an equivalent to Remove Doubles for Bezier curves?
I have been doing a lot of work with curves recently (mostly Bezier because of the greater control) and I have stumbled across an issue, I can't seem to find an equivalent option to Remove Doubles used for meshes. Is there a way to merge all vertices along a curve within a given distance?

For clarification, a double is considered two vertices in the same space (same coordinates), but part of different segment strings. For example, you may have a cyclic curve, three segments  of which are duplicated, and not part of the one coherent whole of the cyclic curve.

do you mean like if you accidentally hit extrude on a point and don't realize it, and haven't moved it away, then yo have zombie points?

@zeffii Exactly, you get weird black ghost lines, and ends up you have a whole string of them

You can only delete vertices or segments, not sure if it will work as expected if there was an option to merge vertices since it will have to create new values for the handles.

Would-be duplicate: http://blender.stackexchange.com/q/23152/599

Please describe in more detail by what you mean with 'doubles'. It can be interpreted in a few ways, and in some very un-useful ways.

There is no equivalent to Remove Doubles for Bezier Curves. This is likely due to the difference in the nature of Curves versus Meshes. As Denis stated, if the two points have different handle positions, how should this be, um, handled? ;-) Should the handle positions be averaged together? Also, Remove Doubles can just merge vertices based on a distance threshold no matter how many edges are connected to it, but Curves are fundamentally different since a point cannot have more than two segments connected to it. Simply put, Curves are linear while Meshes are non-linear.
This doesn't necessarily mean such a feature couldn't be implemented, but it would have limited use cases, and for non-identical doubles it would have to make reaching assumptions about how you want your points merged. For example, if your Curve doesn't cross itself you may be alright, but if it does it could easily end up getting merged at the intersection and the path rerouted in an unexpected way. Here's a screen shot to illustrate what could happen hypothetically:

In conclusion, it could be useful in cases where the doubles lie right on top of one another, but at higher distance thresholds could produce unexpected results. Such a feature could be useful for certain situations, such as for removing points lying on top of one another that you can't see.
For now, you could find such disconnected points by selecting at least one point on each of your curve segments you intend to keep, using Select Linked CtrlL, Hiding them H, then Select All A and Delete X the disconnected left-over points. Then Un-Hide AltH the segments you will keep.

I know what you mean, and I encountered this need just yesterday.  While it is not in stock Blender, there is a feature for this in BlenderCAM:
https://github.com/vilemnovak/blendercam/wiki/Blendercam-Tools#c-remove-doubles
It's called "C-Remove Doubles" -- probably short for curve remove doubles.  It works by converting the curve to a mesh, removing the doubles, then converting back again.  There is a warning about it removing beziers so it might not do exactly what you want.  But it worked for me.

Here is my equivalent of remove doubles on curve as addon:
https://github.com/crantisz/blender-curve-remove-doubles-addon


text:
How to share variable among more than 2 operation
I have a question about blender's python script.
I would like to share variables among more than two operations, however I don't know how to.
If I use global variable, it's easy to solve this problem.
selected_faces = []
class SelectFace(bpy.types.Operator):
    bl_label = "Select Face"
    def execute(self, context):
        global selected_faces
        selected_faces = ...   # get selected faces.
        .....
class OperationAboutSelectedFaces(bpy.types.Operator):
    bl_label = "Operation About selected Face"
    def execute(self, context):
        global selected_faces
        # some operation to "selected_faces"

However, I want to avoid using global variable.
So, I would like to rewrite this code as follows...
class SelectFace(bpy.types.Operator):
    bl_label = "Select Face"
    def execute(self, context):
        selected_faces = ... # get selected faces.
        .....
class OperationAboutSelectedFaces(bpy.types.Operator):
    bl_label = "Operation About selected Face"
    def execute(self, context):
        # some operation to "selected_faces"

Assuming operation sequence are as follows.

"Select Face"
"Operation About selected faces"

Thanks!

see this question, this answer and this

I tried this one. However this solution makes error AttributeError: 'NoneType' object has no attribute 'operator' because class is derived from bpy.types.Operator. Is there any solutions passed variables between bpy.types.Operator?

Both of your classes are global, you can store arbitrary data on them if you really have to: SelectFace.your_global = 123

Can't you pass your selected faces into the constructor of your derived class?  Create a constructor (__init__) and pass your selected_faces into it.  It would be something like this (check syntax):  def  __init__(self, selectedFaces):

@nutti is this your answer it is just a comment ?

Yes it's a comment.

Oh, sorry. I didn't know that answer must be a complete solution. I post the problem here again.
I add below code in __init__ constructor.
self.selected_faces = SelectFace.selected_faces
However self.selected_faces is NoneType.

I could solve this problem.
Solution is shown below.

Create user defined class which has properties you want.
Register class to bpy.types.Scene.XXXXX when add-on is started
Get data from bpy.context.scene.XXXXX
Unregister class to bpy.types.Scene.XXXXX when add-on is stopped

class SelectFaceProp():
    selected_faces = None

class SelectFace(bpy.types.Operator):
    bl_label = "Select Face"
    def execute(self, context):
        props = bpy.context.scene.sf_props
        props.selected_faces = ... # get selected faces.
        .....
class OperationAboutSelectedFaces(bpy.types.Operator):
    bl_label = "Operation About selected Face"
    def execute(self, context):
        props = bpy.context.scene.sf_props
        # some operation to "props.selected_faces"

def register():
    bpy.types.Scene.sf_props = SelectFaceProp()

def unregister():
    del bpy.types.Scene.sf_props

Thank you!!!

Finally, I solved this problem using static variable.
class SelectFace(bpy.types.Operator):
    bl_label = "Select Face"
    selected_faces = None
    def __init__(self):
        SelectFace.selected_faces = None
    def execute(self, context):
        SelectFace.selected_faces = ... # get selected faces.
        .....
class OperationAboutSelectedFaces(bpy.types.Operator):
    bl_label = "Operation About selected Face"
    def __init__(self):
        selected_faces = SelectFace.selected_faces
    def execute(self, context):
        # some operation to "selected_faces"

Thanks for your advice.

You should not use global or static variables, the proper concept to use is Blender's context. Note that this is not a Python mechanism, but something provided by Blender.
The context keeps track of the state of Blender in things such as 'what is the selected scene? what is the active object? what is the current selection?'. This information can then be used by all of Blender's operators, not just your own. Operators, in turn, also affect the context, by for example, modifying the current selection.
If you bypass the context, there will be some inconsistencies, such as operators working on your previous selection, because you never changed it in the context.
How to set that a given face is selected:
face.selected = True

Hot to get all selected faces in a mesh:
selected_faces = [face for face in mesh.faces if face.select]

The mesh can be obtained from the context that is passed as an argument to the operator's execute.

Yeah, I don't want to use global and static variable too. However, there is no way to pass variable between bpy.types.Operators. However I tried to store bpy.types.Scene.XXX, It doesn't work...

You can store new properties in anything that is an ID. Scene should indeed work, as would an operator, but it really needs to be a new Blender property, not just a python variable. See bpy.props

OK. By the way, is there any way to share PointerProperty? I can share IntProperty/FloatProperty, but I can't share PointerProperty.


text:
Multiple TEXTURE Displacements (mapping) in one scene
This might be a bit too special but I thought I'd just give it a try on this forum:
I have a meadow scene. And I want to have a trail running through it. I did use a displacement modifier on the small hills in the scene, and on the trail itself.
I did paint in the texture of the trail, because it should be a different one than the texture "under" the grass (as seen in the pic).

Now I want both textures ("brown soil under the grass" AND the "trail texture") to have a normal, displacement, occlusion, specularity and a diffuse map. But...

I only have ONE displacement connector in the material output node where I would have to put in the normal map(s)...

When I use a displacement modifier I can't place it in reference to the coordinates I already set up for the general seamless texture - so the "bumping" applies to the whole mesh and is way to big.

How can I apply multiple textures AND THEIR MAPS to certain areas on a single plane with the same texture coordinates as in their nodes??

Question: do you want to use both of them in combination, or one in some areas and the other one in other areas?

I wouldn't use the displace node input, it's nothing else than a bump map, but with less control over distance and height than with a Vector-Bump. There's an experimental tessalation feature, but that doesn't really work. Normals should go into a normal input. You can mix normal and bump maps just as you would do with diffuse maps. You got only one diffuse input, too, right? ;)

Yes I want to use both of 'em in different areas. Like I said: The stony trail needs to be bumpy and the brown soil also BUT with the exact scale and coordinates within the node editor for the texture itself. So if I put in the displacement map and put that in a bump node that should do the trick? Then I wouldn't need a displacement modifier for the displacement map. I would just connect the displacement map (in a image texture node) to a bump node as I would do (or did) for the normal map. Right?


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Can vertex groups be passed to subsequent modifiers in Geometry Nodes?
Can the vertex group attributes be passed to subsequent modifiers in Geometry Nodes? For me, the vertex groups are lost when I instantiate the instance meshes (cubes in my example).

why don't you just move the bevel modifier before the gn modifier?

Just as @Chris said, my thoughts exactly. Or instead of using a vertex group, there are other methods for beveling as well: use a bevel weight on the edges. This will also work when you place the Bevel modifier after the GN modifier, however then you will have to use a Realize Instances node (but this does not help for vertex groups, in this case I would change the order as well).

May I recommend to read these posts : get Vertex Group to survive Geometry Nodes  and Transfer (float) vertex-attribute to vertex-weight, to allow GeoNodes to control subsequent Armature binding ?

I was just interested in the possibility transferring vertex group data for the use in subsequent modifiers. I'll read the link by StefLAncien. Thank you.


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Geometry nodes: How to snap curves points to nearest surface?
I would like to snap all distributed curve points to the nearest surface of the source. See my example.
In my example I'm distributing generated mesh lines on a source mesh (Torus). My goal is to align all the mesh line points onto the source surface. So the lines are "snapping to the surface" / lying on the surface.
Any ideas? Thank you!

To be honest I don't know how to raycast along the source normals.

If you plug the Is Hit socket of the Raycast node to the Selection socket of the Set Position node, you will see that some points are not projectable along the torus normal. Consequently, their Hit Position is (0,0,0), generating the lines to object origin. I need more time to investigate why projection fails. My intuition is that it is when the line is tangent to the normal... Do you have a look at the Shrinkwrap Hair Curves node ?

Are you looking for "just" this case (a torus and straight lines) or a more/very general approach ?

Thank you. I think I've found a first solution to use it for my further work. See my answer below.

I found a solution as a basis for further work.
The basically principle:
I need a projection source for the raycast node to get the ray directions around the source mesh. To achieve this I take the source mesh, extrude it a bit and flip its faces to point the normals back to the source. To get the point normals infos, I capture them from the extruded mesh and connect the data to the raycast node.
It's not perfect, but works in most situations. Thank you for your time.
See my example.


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How to execute a function directly after user input
I'm new to python.
I've an input field and would like to execute a function, after the user typed in a string and pressed the return key.
The basic routine already works, but I use a button to execute the function to process the user input.
I would like to know if there's a way to use the return key instead of excuting the function by pressing a button.
Basically: The user types something in and press return: the funtion executes.
Thank you
Chris

You could use Application Handlers (bpy.app.handlers) or Message Bus (bpy.msgbus) to track if something changes(some property in this case). Handler might get very intense since it would probably have to run constantly, so Message Bus might be way better if possible.

Or see this: https://blender.stackexchange.com/questions/38274/generate-an-event-or-function-callback-when-a-stringproperty-is-changed-via-user

Thank you Martynas. I'll give it a try.