text:
What does the cuda option do in blender?

As I understand, this thing just makes your gpu render scene with your cpu, but I can't see any good results using it with cycle render.Can you tell me how to activate it right, or why won't it do anythng?

Short answer: If you have a good graphics card, when you switch to rendered viewport, it'll be much faster to move around and see the results, you can use this to your advantage, but the result will be the same/look the same, only the rendering time will change

CUDA uses the CUDA cores of your GPU to do the rendering. In short, they're stream processors and do not affect how the output render looks. There is no difference between that and your GPU, in essence. I don't even think you can run an NVIDIA card without using CUDA cores for rendering for two reasons: 1. it may turn to molasses (analogous to running a PC on a USB ver. 1.0 instead of a harddrive), and 2. Blender won't know how. This is specific to NVIDIA. OpenCL is used for AMD cards. Since you have an NVIDIA card enabled, it will process the render. Otherwise, you're going to have to use your CPU. Do whatever is faster. I use a 635M and it is faster for me to use my Intel i5 3210 than the graphics card. You can read more about this here: https://docs.blender.org/manual/en/latest/render/cycles/gpu_rendering.html
Also this reference is good for explaining what CUDA cores are: https://www.lifewire.com/what-is-nvidia-cuda-834095

oh, yea I enabled gpu compute, and same scene rendered in 33 secs, which is great,but I don't understand,why is it showing you only one yellow box,which indicates ,that it is using only one core,can someone explain  this to me?

A GPU only has one core. It's a GPU. There is no multi-thread processing in the same way that a CPU has multi-threads. This is why to take advantage of a GPU, your tile size should be much bigger (think 10x or more) because a GPU can process huge amounts of data simultaneously, although only one core on a GPU does the work in the end. Think of it this way: a GPU has one processor and multiple pipe lines to it. A CPU has multiple cores but only two pipe lines per core. That's the difference.

You're still using CPU as your compute device in the render settings tab. So, even though you've enabled CUDA rendering, you haven't turned it on. Once you turn it on, you'll see a noticable speedup.
Bear in mind that you're limited by your GPU's memory, so, for example, a 1GB card can only render <= 1GB of data. You might run into situations where the render fails because you've run out of memory, and you'll either have to a)reduce GPU memory usage by closing other programs that use your GPU and reducing the resolution of textures/assets in your scene, or b) switch to CPU render.


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How to batch rename materials or auto assign them to the name of the texture file
I'm currently working on porting a section of a world/map from one game to use in source filmmaker. I've managed to import the section I wanted and I'm stuck at a very slow and repetitive process.
What I have is dozens of objects (which I imported directly from my game), the material names were assigned based on the name of the object and the texture was set accordingly.
So lets say an object I imported is called chair, and this object has 3 materials or so. Each material will be named chair.001, chair.002, chair.003, etc etc. Now, the texture files/images are named correctly, lets say the textures are named chairwood chairclooth chairmetal or something of that sort. What I need is to be able to automatically merge the names of the materials with the textures they are assigned, so whatever the filename is the material is automatically changed to it. Several of the objects I have use the same texture file whilst having differently named materials, so you can see why its a royal pain.
Pretty much I need to know if I can do any of the following things with or or without existing addons/scripts or default tools in blender.
1) Can you select/batch multiple materials and rename them to all have the same name?
2) Convert/export textures to have them the same as the material?
I've included a imgur link of what I'm trying to explain, maybe it'll be easier to understand what I'm getting at
https://i.sstatic.net/Dm86q.png

Using blender internal, the textures can be found in bpy.data.textures. By looping through this you can easily match the texture name to the image it has.
import bpy

for tex in bpy.data.textures:
    if tex.type == 'IMAGE':
        tex.name = tex.image.name

Usually the image name is its filename without extension, if you have image names with extensions, you can use os.path.splitext to remove the extension.
tex.name = os.path.splitext(tex.image.name)[0]

Not entirely sure what you mean. The code you have provided me, is this something I can just copy paste into text editor and run or is it just a example? I’m still relatively new to Blender so I haven’t picked up on the name of each tool/section/options it has, mainly learned stuff through testing things out. How would I access blender internal, is that some sort of script/text file editable within blender? Forgive me if I sound stupid lol, this is my first time making a help thread on Blender.

@DrJoseEvil Blender internal is the render engine, the way your textures show in the outliner means that is what your materials are setup for. The above script should just do what you want as it is, paste it into blenders text editor and run it, then check things look right before saving.

The script is giving me a error
On line 5
AttributeError: 'NoneType' object has no attribute 'name'
Error: Python script fail, look in the console for now...

Select your desired object and copy and past the script to the console, hit enter twice and your good to go.
import bpy
import os
# Set the material_index to 0 ( the first material )
bpy.context.object.active_material_index = 0
# Go through list of materials assigned to selected object
for material in bpy.context.object.data.materials:
    material_index = bpy.context.object.active_material_index
    old_name = material.name
    try:
        # Get its first material slot
        material = bpy.context.active_object.material_slots[material_index].material
        # Get the nodes in the node tree
        nodes = material.node_tree.nodes
        # Get a principled node
        principled = next(n for n in nodes if n.type == 'BSDF_PRINCIPLED')
        # Get the slot for 'base color'
        base_color = principled.inputs['Base Color'] #Or principled.inputs[0]
        # Get the link
        link = base_color.links[0]
        link_node = link.from_node
        # Rename the material to the image name excluding the extension
        material.name = os.path.splitext( link_node.image.name )[0]
        # Print the results
        print( "Material Old Name:", old_name, )
        print( "Material New Name:", material.name )
        print( )
    except:
        print( 'not found' )
    # Add 1 to the material_index count ( move to the next material )
    bpy.context.object.active_material_index +=1

Source: https://blenderartists.org/t/batch-rename-materials-with-file-names-of-linked-texture/1215110/5

Recommend pasting into and running scripts from text editor.  _Having blank lines where indented will cause an error in blender's py console _

source: Stack Exchange

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

sort: votes


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"Correct" way to add texture for a photo print in a scene. Fix "over-exposure"
Total beginner to Blender here, so please pardon my general ignorance.
I'm trying to render product shots of some photographic prints for my wife. I've bought an interior scene from evermotion which already had some prints on the wall, and am trying to substitute her photos for those prints.
To do this, I've deleted the meshes for the existing prints (they were using a texture atlas for all of the prints, which seemed like unnecessary additional complexity for now), added in planes for the new prints, and used a simple "image texture" material on them. This approximately works, but the photos look over exposed when I render -- this is the problem I'm trying to solve.
Moreover, I'm a bit confused about what's actually happening: she sent me JPEGs of developed RAW files which had already had exposure, tone-mapping, gamma, etc applied in Lightroom. My understanding of 3D graphics was that you generally wanted to work on linear data and then apply the tone-map and gamma to the final render. So I guess I'm not surprised that it's come out wrong, but I'm at a bit of a loss to understand the best path to making it "right".
Would appreciate any pointers on this! Thanks!

is hard to say without an example. you could check if in the scene properties under the color management your render view is on Filmic.  it may help lowering down the exposure

Thanks Virgil. The render is already set to Filmic. What info would you need to help diagnose this? I'm still at the stage of just stumbling through the UI, but can try to find stuff if you can give me an idea of what to look for.

well there are a lot of things that could add to the over exposure in the final render. it depends if you are using the Cycles render engine or the Blender Internal render. it may depend on your material and the position of the lights and so on. so usually the more you can let us know the better. if you don't want to share the render try other jpeg images and see if you get the same result and if yes then show them.

Ok, got it. It occurred to me that I should look at the materials that the original used and see if I can replicate that. So I'll have a go at that first. If I can't figure it out with that, I'll share some screenshots. And I'm using Cycles, FWIW.

Ok, so I think here's what's happening: the original scene specified Exposure 1.6 in the Color Management section of the scene properties. Reducing that to 0 gets the prints back to the expected exposure but of course then the rest of the scene is too dark.
I can think of 3 potential paths forward:

Change the material on the prints to apply -1.6 stops of exposure adjustment... somehow.
Remove the scene's 1.6 stops and play with the lights to get more light in the scene.
Somehow change the material for the prints to something that ignores the lighting and just sends back texels.

Of those, (2) seems like the least hacky to me, so I guess I'll try to figure that out. It still seems like there's potentially multiple layers of tone-mapping occurring, but for now I'll just try to solve one problem at a time.

so as far as I understand the evermotion project came with a .blend file with the scene already configured at + 1.6 exposure. while it works ok for all the current objects in the scene, it does not if you import some of your images. the easiest thing I can imagine is by modifying the prints material in the node editor. the tab Color should have what you need (like bright/contrast, gamma, curves and so on). place the node you need between your image texture node and the shader node and then properly adjusting those according to your scene or to your like. hope this helps

Ok, here's what I ended up doing. Thank you @virgil-sisoe for the pointers.
First up, I may have been overly concerned about gamma correction: it looks like Blender automatically gamma "uncorrects" (wrongs?) texture data when it's loaded, so the output of the texture node can be assumed to be linear.
From there I added a "Separate RGB" node, and added a Multiply node on each of its 3 outputs, followed by a "Combine RGB" node. I set each of the multiply nodes to 0.5, so -1 stop.
(arguably it should have been -1.6 stops, but -1 looked right given the brightness of the rest of the scene).
I added gamma nodes to the input and output, but have the input gamma set to 1 (so no gamma adjustment), and the output a little over 1 to add just a touch of contrast.
The last thing I did was to switch from the principled BSDF shader to the diffuse BSDF shader. I figured that I only want diffuse here, and I don't yet fully understand the principled shader.
This looks ok, and I think it will suffice for my current purposes.
Here's what I ended up with:

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


text:
Why blender render produce different data even if input data is the same.
Why blender render produce different data even if input data is the same. I mean, i am trying to compare two images rendered by blender, they are identical overall, but the value differs in 3-7 bytes (if work with an image as with byte array)

Date/timestamp? Rendertime? Presumably some metadata. Update your question to add more detail - such as details of how/where you spotted the differences. This is too vague as it stands.


text:
How can I just see the texture (and not the mesh) when I do my final render?
I make this and I unwrap it

then I put the texture on it but how can only the texture appear when I render it ? And not the shape of the mesh. (Like she appears in the object mode on the left of the screen) It's possible ?

Sorry I begin, thank you !

Possible duplicate: https://blender.stackexchange.com/questions/46424/add-a-transparent-image-on-top-of-a-material

Related: https://blender.stackexchange.com/questions/93686/transluscent-leaf-using-principled-shader/93845#93845

Thank you ! Honestly I tried to make it but I still don't use the nodes.
There is not a "easier" way for a beginner like me ?


text:
How to make volumetrics work
I've been reading a lot about this, but I can't find the solution. Anything I've tried so far hasn't helped at all to solve my problem.
The scene is simple. There's a sun light outside which is blueish because this is gonna be a night time scene. I need a volumetric (god-ray like) light coming through the window. In the screenshots you can see my settings.
In order to use the sun light for this, I created a box that surrounds my scene and I've made the volume scatter material for it. I read that .1 is a good place to start at, but it makes my scene completely black. If I get to .001 I can see but I don't really think it creates any volumetric light.

I tried both a 1cm sun and a 1m sun, but nothing changes. sun strength at 50,000. I tried even more nothing changes and it seems stupid for me that I have to go higher to make this work, because I 've seen a lot of people working with much less and it works just fine.
Any help would be appreciated.

Try increasing transparency bounces in Properties editor > Render tab > Light Paths panel. Note also to use more than 1 bounce for lamp settings

I tried but nothing changes apparently

yes I am using glass

even by moving the glass away (it's a different piece from the window), It's still very dark.


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Random texture coordinates on array
I modeled some logs that together compose a wall. I modeled one and texturized it, then applied an array modifier. Problem is that they all look the same. is there a way to randomize the texture coordinates on each of them? Or am I forced to copy and paste them "manually" and avoid the array modifier?

If you use UV coordinates they're going to be identical in all the meshes obviously. But you can often get away with using world space or object space coordinates.

Quite late to answer, but this might help you out.
https://www.youtube.com/watch?v=Q0YmpkUeVYg

The answer in comments is what you need, but it is related to color and not coordinate space.  I usually do something like this:

As of Blender 2.8, there's a UV offset parameter in the Array modifier that should do the trick.  Not exactly random, but it might give you good enough results.

As in one of the comment-inks above, you can actually make the result as random as you like by not using the UV directly. Instead use the offset-UV to look up into a noise texture. and use whatever you find there as your actual UV.


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cycle crashing while rendering but no error pops up
What the title says, basically.
I had issues with my pc, but I've just changed CPU, motherboard, and Hard Drive and I was able to render more complex scenes before with no issue at all. My drivers are up to date.
My PC:
CPU: AMD Ryzen 7 1700
GPU: Gtx Geforce 1060
RAM: 16gb DDR4
MOTHERBOARD: ROG Strix B350F Gaming
Using Blender 2.79

This question appears to be about an issue caused by a bug in Blender and should be reported to the official bug tracker: https://developer.blender.org/

but there's no temporary solution in the meantime?

Do this crash only occurs in particular project or in every project?

I've tried also other projects that I rendered months ago with no issue and it occurs.


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baking normal maps for games. Smooth shading issues
I've been working on some game models lately, and I was wondering if the smoothing shading is gonna be an issue?

I was wondering: do I have to use autosmooth  or sharp edges and make it look better? Because I've seen some people doing that and others don't care about it. What's the right way to proceed for the best result? I'm gonna bake normals and texture the model in substance painter, in case the info is relevant. Obviously, the high poly model shading looks ok after with a subdivision surface modifier.
Hopefully I've been clear!

If that's for tileable object like panel (from screenshot looks like it isn't) then yes use smoothing groups / hard edges and don't use normal maps.  If you are going to bake details from highpoly into normal map then it doesn't matter, normal map will handle with shading

oh great, that's what I needed. As long as I apply normal maps to the low poly, they will handle it and it will look good. Great.

If you get the bakes that looks good they should be fine. If it's a glossy surface then you can get stair casing in the normals where they are nearly flat since 8-bit reproduces only a limited number of angles. The simplest way is to add hard edges the windows edge to make it perfectly flat.
Triangulate meshes before baking them. Software does not always agree how to split the faces so it's good to make sure you decide.
You should avoid thin triangles. Thin triangles can act as a hard edge since they usually don't get enough pixels to bend where normals changes. Perfectly flat surfaces with no normal changes can handle thin triangles though.
Separate all hard edged faces on separate UV-islands and give them enough margin.
If they are to close they might fight over the pixels. Remember that mip-maps will be in lower resolution.
Align bevels and other details with pixels where possible. Prioritise sharper bevels.
Give detailed areas of your mesh a bit more UV space so the smaller triangles will get what they need.
You can get distortions and other artefacts where the normals bends but I think it's better if you encounter them, figuring out way they appear and how to mitigate them.

But I was wondering if there's simply THE right way to do it.. marking sharp edges give a completely different smoothing effect, so i guess the results would be different, and probably one would be wrong.. unless substance painter takes into consideratino the high poly (and smoothed) model and reflects that onto the low poly one?

When you bake, the normals get transferred from the high poly to the low polys normal texture. The bake ray traces from the low poly using its normals so the result will not be completely the same if you use hard instead of smooth edges. But you need to figure out what works best for each problem. I might get your question wrong... do you have a more specific problem? Screenshot?

I've ran some tests, and it makes a difference indeed. Sometimes not too obvious, other times it kinda ruins the shading. Thx anyway

Yes, you should use smoothing (in particular smoothing groups) and hard edge techniques to get good results, whenever you don't bake from high poly objects.
The reason for this is that Blender exports the normals in every export format that is suitable for Substance Painter. You should always try to create your model in Blender as close as possible to the desired result. It saves a lot of time and headache.

"whenever you don't bake from high poly objects." <-- so, if I want to bake normals from an high poly object to a low poly one, technically I would not need to make edges sharp and get a good looking smooth in the viewport?

It's not necessary for flat areas but you still might get better results if you create additional edge loops in the more obvious parts of the mesh.

yeah either adding edge loops or marking sharp help a lot


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Blender showing me textures even though the nodes are not linked to the principled shader
Basically what the title says. I import textures made with substance painter into blender, and as soon as I add them as a node, they show up in the viewport preview, and when I click on them it basically switches between them. For example, I click on the albedo node, it shows me the texture in the viewport. I click on the metallic node, it shows me the metallic node in the viewport, and so on. It seems like I've activated some kind of instant preview or something? Hopefully it's clear.

What's wrong?

I don't see anything wrong in the setup above. Textured shading mode is what shows preview of the texture from currently selected Image Texture node on the mesh.

ah.. I thought you still had to link the nodes to the principled shader in order for them to show up. My bad then, I guess.

You do if you want them rendered. Selecting them lets you see the texture on your object in textured viewport shading, but it won't be factored into rendering unless the nodes are connected.

alright thanks for the help


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Unwrap doesn't work properly
I've been working on a model and I want to unwrap it in order to apply textures.
Problem is, when I click on "unwrap", the model doesn't take all the space available, and some parts are stretched in a very weird way, even tho (I believe) the unwrap was done correctly, and anyway I think it'd be impossible for it to look like that, even if I made a mistake.
The scale is 1 1 1 (I've applied both rotation and scale).
Furthermore, when I click on "unwrap" once again, nothing changes, it looks like it is stuck, somehow.
Any ideas?
Thanks.

this is the stretched part of the model. As you can see,it's basically a cylinder, and you can notice my seams.

The red outlines on your vertices in the UV editor show that you've pinned those vertices. Pinning prevents Unwrap from moving them again, which is useful in allowing you to retain any parts you are happy with. Pin by pressing 'P' and unpin with 'Alt-P' (within the UV Editor).
To address the UVs not taking up enough space: you can manually grab/rotate/scale in the UV editor to directly fix this. Selecting vertices and pressing 'L' will select all linked parts of the mesh by UV seam/island.
So - again, in UV editor - if you select a vertex in the tall part of your mesh, hit 'L' to get all linked, 'alt-P' to unpin it, then in the 3D view do 'u > Unwrap' once again, you should see a revised unwrap of the problematic part.
And as Per's answer above -- other automatic unwrapping types are also available, such as projection from view -- but knowing how to manually re-unwrap subparts of your mesh is always useful.

thanks for your help, I must have accidentally press the P button.

@Raio Boss don't post thank you comments, upvote the post instead. If it completely solved your problem consider marking it as accepted

Go into orthogonal view
Go to the front view
Select the front faces
Go to UV and choose project from view
Rinse and repeat for the back and if necessary sides.
Remember you can select the individual UVs and move and scale them on the uv map.


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Array of 3D circles with same center, and same distance between them, but different radio
I am new at blender, and this is where I am currently:

I got an initial circle, and applied an Array modifier (with an empty object in the center as object offset), followed by the Solidify modifier so after the scale the shape will keep the thickness. But the distance between the circles is not the same. How can I keep the distance the same?
the shape of each circle should finally look like this:

Any ideas? THANKS!
Reference image of the project:

Related https://blender.stackexchange.com/questions/67440/making-a-radio-wave-transmission-waves

It looks as if the intervals along your radii are all the same .. so this is an option:

Order up a mesh circle, sides divisible by 4, fan fill.
CtrlShiftB Bevel the center vertex to desired diameter
Select the radial edges and  CtrlR add edge loops to the desired number.. (right-click out of the operation to leave it without sliding the loops)
Select every other face ring ...
.. and delete.

This is a case where the double mirror would be perfect: delete three quadrants then ~2 more quads from each end, apply x+y mirror, you only have to worry about fiddling with 1/4 as much.

True.. and I've just noticed  he might want aisles with parallel sides ..

Create a circle (in this case 32 sides.) Remove 1/2 the vertices and then 1/2 again to give you an arc, i.e. 1/4 of a circle. Add mirror modifier in both x and y to give yourself an full circle again. Add a solidify modifier to desired thickness. Apply both modifiers. Shift+D to duplicate. Scale in the x and y only in Object mode. For the 2nd ring 1.5x, 1.5y and 1z (unless you want the thickness in the Z to increase. Switch to edit mode and select the inner two rings, (alt RMB on one then alt+shift RMB on the 2nd.) Reduce scale to match first ring. Repeat as desired.

Double-mirroring is a useful technique while modeling sometimes, but it really doesn't seem to be doing anything here for you. Also it's not clear how you're reducing the scale (width) of the rings without reducing their overall size.


text:
How do I get from the default view to the 3D Editor View?

How do I get from here:
To Here:

Ctrl+upkey with the mouse cursor in the windows, the same to get out.
Nkey and tkey to pop side panels.

Thank you Raul. I got the "Transform" on the right but still don't have the "Translate" field on the bottom left. How do I get the "Transform" to come up?

Click the translate widget (the red green blue arrows)

As thilbsert said, that last panel is a dynamic panel that changes according to the function you do, if you use the widget (the colored arrows that pop from the center of an object) and you move the object the translate panel will pop, also others like rotate, scale etc, lots of info there.


text:
How can I hide all the animation controls?
I am only interested in modeling and not animation. Is there a way I can hide all the animation related panels from the blender interface? They take up screen real estate that I could use for other tools.

Either change the view type

or just combine one view with another by right clicking the edge between them

Remember you can Switch to, Create New and Duplicate Screen layouts from the drop down at the top of the screen.


text:
Compositing issue when adding gaussian noise to image
I need to add random gaussian noise to images rendered with EEVEE. I thought about python coding this at the pixel level but I'm having issues with color spaces, so I came back to the compositor to get it.
I generated my noise and want to add this to the rendered image. While the noise appears on the rendered object, the background does not get any noise. I'm probably forgetting to check a parameter but can't have it, maybe related to depth ?
here is the noise image  and there the very simple node system . The result after compositing is here
To check what's happening, I also did a difference with the noise image again and obtain the initial rendered image, meaning that although the noise does not appear in the background of the image, it is still computed and removed.
Any clue of what's missing here?
Thank you!

If you "add", you are making things brighter. But the background is already white, the top of the scale. You might want to subtract or multiply the noise.

https://blender.stackexchange.com/questions/84546/adding-random-noise-to-rendered-images

Thanks for your answers @Pullup, I'm a bit confused. The background being grey, so it seems there's still room for a few levels for an increase so I should see the dots. Am I wrong ?

I would try making the noise much larger to test the effect of your nodes.

Thanks @3pointedit, tried that, but that does not seem to provide good results either..


text:
How to make a growing text animation?
I'm trying to replicate a text animation from GreyScaleGorilla (https://www.youtube.com/watch?v=NMMNTaI4wD8&t=2s) but can't find the right way to do it in blender.
I tried beveling the text, transforming the text to curve or mesh and applying different modifiers, I even tried animation nodes. But as my nickname suggest I am a noob in blender so I need some guidance here.
Thank you very much.

Have you tried the Build Modifier? Text will have to be a Mesh first.

Yes, but does not work.

Growing Text -   Rendered with OpenGL in Blender 2.77a -
Edit dated 3rd Dec. 2018 -
Whilst as you point out this is a trifle complex for your needs, I was remiss in the original answer below, not producing the final effect shown in your Youtube video link.

The original answer deals primarily with a method of 'box masking' to simulate mesh growth without disturbing that mesh and consequently avoiding the tendency to end up with ugly surface streaks.
This added section deals with the final visual effect you were hoping to achieve, albeit seeking a simpler solution.
For those who have watched the video and may be interested in how it might be achieved in Blender, most steps were as described below.
Viz - This new text was also extruded, converted to mesh, and parted to be individual letters, although I don't think the last step was entirely necessary.
The letters' forward and rear faces were removed to another layer so the originals end up as hollow shells.  (much as a cylinder without end caps)
These were 'solidified' with that modifier, ready for their removed faces in the other layer to be extruded, coloured black, and used to fill in the hollowed letters.
As for the growth animation of their white exterior, the method described below in the original answer was used again here.
-==============-
Original post -
This isn't exactly "Noob" territory but it does pretty much 'Write" the text as requested.

Rather than interfere with the text's mesh, I find it less troublesome to leave the text as is and wrap each letter in a similarly shaped 3D "invisibility cloak". (mask)
The mask's end-cap is then progressively moved back with some shape-shifting method made to follow a letter's contours, revealing that part of the mesh that progressively ends up outside the mask.
Mask Z fighting (with it's own surfaces) and shading distortions aren't of concern because of it's invisibility.
OpenGL masking is used here because they can be discriminatory and 3D meshed (bevelled) two essential elements for this effect.
To this end the text is converted to mesh and letters separated to become individual objects.
Within each, a "Curve Path" shaped the same as the letter is added and that bevelled using a square plane curve.  (The plane has no face and converted to a curve with ALT-C)
Letter segments or sections are therefore wrapped in a rectangular 'pipe' which is much the same shape as the letter it's concealing.  All of the masks are assigned the same Material Slot.
(For masking - Diffuse at half, Material --> Transparency --> Alpha set to 0.008, and both Speculars set to zero)

Because these 'pipes' are left as curve-paths, their start  "Resolution" slider in the path's Geometry tab, can be keyframed to roll back the pipe's end-cap and progressively reveal letters as though being newly formed or written.
With letters in such close proximity and when viewed at an angle, a mask can end up cutting holes in an adjacent and previously revealed letter.
Some knowledge therefore as to what makes these masks tick is going to be more than a little helpful, particularly in the way their discrimination works as related to the 'age' of objects to be masked.  It's what makes them so useful and allows letters already revealed to remain unscathed by 'younger' masks.
Read up on this here ->
How to put a mask into 3d space
If you prefer to use Blender's Internal Render then it's own layer masking or perhaps nodes will have to be employed, along with any post production necessary.  Similarly with Chroma Key.

Thank you very much for your reponse but that method does not achive the look I need to get, also it is way complex for the simple effect I want to achieve. There is no easier way to sweep a text object and animate it? In C4D you can do it in 1 minute.

You are right of course.   I see Blender as I would a manual lathe or other machine. It isn't a commercial product - providing one click solutions.  It does however contain a myriad of 'levers, dials and cogs' that give it enormous flexibility that can achieve amazing modelling and video effects.  There are people who frequent this site, who also write code for Blender that would probably achieve the result you're after.  It was why I waited a few days for something better. Hoping you find a solution...

I've tried to replace the faulty gif at the top and it loads the new one but dumps a copy of the old one in it's place!  I renamed the newy and the same thing happens.


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Cannot open any video files with Blender
I am completely new to video editing.  After seeing a few Youtube videos, I realised Blender suited my needs well.  Unfortunately, I have failed to open pretty much all kinds of video files.  After reading, old forum/blender.SX posts, I thought my distribution's Blender build did not enable ffmpeg support. So I downloaded the tarball from blender.org, no luck.  Every time I get a message like this on the UI.

File format is not supported in file '/path/to/file'

It's not that I do not have the codecs, because I regularly re-encode videos with ffmpeg.
OS: Fedora 28
Blender: Fedora repos, and blender.org tarball
$ blender-upstream --version
Blender 2.79 (sub 0)
  build date: 2018-03-22
  build time: 14:39:03
  build commit date: 2018-03-22
  build commit time: 14:10
  build hash: f4dc9f9d68b
  build platform: Linux
  build type: Release
  build c flags:  -Wall -Wcast-align -Werror=implicit-function-declaration \
        -Werror=return-type -Werror=vla -Wstrict-prototypes -Wmissing-prototypes \
        -Wno-char-subscripts -Wno-unknown-pragmas -Wpointer-arith \
        -Wunused-parameter -Wwrite-strings -Wlogical-op -Wundef -Winit-self \
        -Wnonnull -Wmissing-include-dirs -Wno-div-by-zero -Wtype-limits \
        -Wformat-signedness -Wuninitialized -Wredundant-decls -Wshadow \
        -Wno-error=unused-but-set-variable -Wimplicit-fallthrough=5 \
        -fuse-ld=gold -std=gnu11 -msse -pipe -fPIC -funsigned-char \
        -fno-strict-aliasing -msse2
  build c++ flags:  -Wredundant-decls -Wall -Wno-invalid-offsetof -Wno-sign-compare \
        -Wlogical-op -Winit-self -Wmissing-include-dirs -Wno-div-by-zero \
     -Wtype-limits -Werror=return-type -Werror=implicit-function-declaration \
     -Wno-char-subscripts -Wno-unknown-pragmas -Wpointer-arith -Wunused-parameter \
     -Wwrite-strings -Wundef -Wformat-signedness -Wuninitialized -Wundef \
     -Wmissing-declarations -Wimplicit-fallthrough=5 -fuse-ld=gold -std=c++11 \
     -msse -pipe -fPIC -funsigned-char -fno-strict-aliasing -msse2
  build link flags:  -Wl,--version-script='/home/sources/blender-release/source/creator/blender.map'
  build system: CMake
$ blender --version
Blender 2.79 (sub 0)
  build date: 2018-08-10
  build time: 02:58:43
  build commit date: 1970-01-01
  build commit time: 00:00
  build hash: unknown
  build platform: Linux
  build type: Release
  build c flags:  -Wall -Wcast-align -Werror=implicit-function-declaration \
        -Werror=return-type -Werror=vla -Wstrict-prototypes -Wmissing-prototypes \
        -Wno-char-subscripts -Wno-unknown-pragmas -Wpointer-arith \
        -Wunused-parameter -Wwrite-strings -Wlogical-op -Wundef -Winit-self \
        -Wnonnull -Wmissing-include-dirs -Wno-div-by-zero -Wtype-limits \
        -Wformat-signedness -Wuninitialized -Wredundant-decls -Wshadow \
        -Wno-error=unused-but-set-variable -Wimplicit-fallthrough=5 -O2 -g -pipe \
        -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS \
        -fexceptions -fstack-protector-strong -grecord-gcc-switches \
        -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 \
        -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic \
        -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fuse-ld=gold \
        -fopenmp -std=gnu11   -msse -pipe -fPIC -funsigned-char -fno-strict-aliasing -msse2
  build c++ flags:  -Wredundant-decls -Wall -Wno-invalid-offsetof -Wno-sign-compare \
        -Wlogical-op -Winit-self -Wmissing-include-dirs -Wno-div-by-zero -Wtype-limits \
        -Werror=return-type -Werror=implicit-function-declaration -Wno-char-subscripts \
        -Wno-unknown-pragmas -Wpointer-arith -Wunused-parameter -Wwrite-strings -Wundef \
        -Wformat-signedness -Wuninitialized -Wundef -Wmissing-declarations \
        -Wimplicit-fallthrough=5 -O2 -g -pipe -Wall -Werror=format-security \
        -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong \
        -grecord-gcc-switches-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 \
        -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic \
        -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fuse-ld=gold \
        -fopenmp -std=c++11   -msse -pipe -fPIC -funsigned-char -fno-strict-aliasing -msse2
  build link flags:
  build system: CMake


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Mesh shrinking and expanding between shape keys
I'm trying to do a deformation with a mix of bones and shape keys. I created a bone first, attached it to the mesh with an Armature modifier and animated it (only 2 keys). I copied the modifier so that I have as many modifiers as keys. I applied the first key as shape key, the second modifier was not active.  I did the same with the second one then I keyed the shape keys as well.
I'd need your help in the following matter: When I apply the shape keys, the deformation doesn't follow the bone anymore, starting and end position are ok but the mesh shrinks in between the two keys (see 3rd picture).  It really destroys the whole animation...
I tried "preserve volume" when applying the armature modifier as it sounded good but it didn't do anything noticable. Do you have any idea how to keep the mesh the same size throughout the animation?
Your help would be much appreciated!

I'm not sure what you are trying to do... what are the shape keys for? Usually you use them to change the shape of a mesh. The armature on this object is also used to change the shape of the mesh.
So the problem would be that they interfere with each other in some way. Like, let's say a bone squashes a mesh from 100% to 50% of it's height. And now you take 100% as the base, 50% as a shape key. If the bone is now squashing the mesh along with the shape key, than it will squash the mesh to 50% of 50% which is 25%.
More complex deformations and armatures might result in very strange results.

Sorry, the armature might be a bit misleading, I left it there for demonstration purposes, so that you can see how big the difference between the "should be" and the real size is. it doesn't influence the geometry anymore, it's only the shape keys that are deforming the object at this point.
My main issue is that while I did the animation with the bones, the object stayed the same propotion throughout the whole animation but when I applied the keys as shape keys, the mesh shrinks at the in between part of the animation (where I don't have keys)

I see... without talking about your specific mesh you have to keep in mind that shape keys only store positions of vertices, not the transition you did to get them into this position. This means, if you move a mesh by rotation and store it as a shape key, the shape key will not follow the rotation but move all vertices straight from base position to shape key position.

So the only option would be to set as many shape keys as it takes to get a smooth transition between my two "main" frames?
Or can you think of a better solution as to how to get the mesh not to shrink in between?

Best would be to keep the armature. Maybe I post the explanation of what it does as answer where I can attach an image to it as it may help others to understand why this happens.

I agree but I need to export the mesh to another software as gltf so I need the deformation in the mesh.
I'm sure an explanation would be helpful for a lot of people!

I was suspecting that you couldn't keep the armature. Well, as you said, more shape keys seem to be the only way to go. I'll post an answer anyway, maybe it helps other people understand what's going on.

I edited the answer even more, because creating more shape keys only creates more problems. Is there maybe a way of baking the bone deformation and export the resulting animation?

The mesh changing its size is caused by the way the shape key transforms the vertices. You can use different operations (in your case, bone deformation) on a base mesh to create the shape you want, but the shape key only stores information about positions of vertices. To illustrate it here's a simple example:
If you rotate a cube mesh to get the new shape, the shape key doesn't store the path the vertices are moved, so the transition from base mesh to shape key is linear which can result in changing the appearance of the mesh between start and end position.
The top image shows the way how the shape was created by rotating the cube mesh around the 3D cursor.
At the bottom it shows how the transition from the base mesh to the shape key will be performed. As you see, the vertices move in a straight line from start to end position and change the cube's size.
To get the same deformation the bones would create it would be best to keep the armature deforming the mesh. If you can't keep the bones for some reason, inserting more shape keys to get closer to the original deformation causes a problem, since shape keys store the delta transformation: if you set key1 after moving vertices from Z = 0 to Z = 2, and for key2 you move those vertices to Z = 3, then key1 is moving up 2 - 0 = 2 units, and key2 is moving up 3 - 0 = 3 units. If you set both shape keys then the vertices are going up 2 + 3 = 5 units. If you ignore key1 to move them only 3 units you'll have the same problem like before with only one shape key.


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Mesh to Curves without overlap
I have the following mesh:

Using the Edge Paths to Curves and Shortest Edge Paths node (with the Vertex at the 3D-Cursor chosen as the End Vertex) I can convert it into Curves like so:

However this "overlap" between the curves leads to issues when trying to add a profile to them. What I'm trying to achieve is an effect similar to the Skin Modifier.
Is there any way to get the following kind of curve topology?

Not really. A curve cannot branch, each control point on a spline can only have a maximum of two segments connected to it. Either just one segment when it's an endpoint or two segments when it is inbetween two segments. So converting it into a mesh to merge it for example with a Skin modifier as you mentioned is the only way.

@GordonBrinkmann Sorry if I was unclear with my question. I do know that a curve cannot branch, what I meant was how to make one of the curves shorter.

You could try Curve to Mesh > Merge Vertices > Mesh to Curve


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Eevee isn't rendering lighting properly
Like the title says: it doesn't render lighting properly.
Here's an example with cycles:

And here it is (exactly the same settings nothing changed) with eevee:

Here are my pc specs (although it's not great, it passes the minimum requirements:

Intel Core 2 Duo P8400 @2.24GHZ
3gb of RAM
Nvidia Geforce 9600M GT
Windows 10 64-bit

And I checked with Opengl extensions: it does support opengl 3.3

Can you please show light type and material?

I left it on default, this is the default cube you get when you start up blender 2.8, so i don't remember what the material is. But the light is a point light @Kiskit


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why is everything white when i try to paint mesh?

I created a mesh and  unwrap it. Then i  go to texture paint mode and choose diffuse but everything is white and i cant paint anything.

Select all the mesh in Edit mode and in the UV editor choose image you want to paint on.

Make sure you have a target texture for your paint information to go to.  You likely just need to add one (by clicking new texture in the UV/Image view) or choosing one (by click the texture dropdown in the UV/Image view).
I believe everything is white because that is your material diffuse color.


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texture painting color with wrong color

I am trying to texture paint this pawn but for some reason it is not working correctly. Here i am trying to paint this orange but blender is painting it green. when i try to paint it blue blender paints in low intensity red.  I try changing materials, light, objects, normal no change.

Your blend type is set to mix. Change it to add.


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Why my background appears a blue, when I set it transparent?
I am trying to render this image with transparent background, but instead it renders as blue. I have checked the world settings, HDRI. The problem only happens in render and not view port. Problem persist in both eevee and cycles. Any help is appreciated.

You're compositing the blue background in. Enter the compositor and either mute the Mix node or remove it.

Why does using the Alpha create that thin, blue line? I imagined to be proper about things, the Alpha socket could be filled but its result isn't as clean as omitting the Mix Node. Shouldn't it be pixel perfect?

@HelloHiHola What thin blue line are you talking about?

Can't add pictures here but if you drag the Render Layers Alpha into the Composite Alpha socket (looking in Compositor), the results aren't as clean as I would expect. I was curious if you knew why since that seems a formal option of eliminating the blue.

What you're seeing is the background peeking through the non-100% black of the alpha channel due to antialiasing. Create a Viewer node in the compositor and plug the Alpha into the image input and zoom in to the image - you'll see grey pixels between the white and black. Wherever it's grey, that's where you see some blue peek through. To remove this completely you can put a Luminance Key node with high and low set to 1 between the alpha out of the image and the alpha in of the viewer/composite node.


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spring effect on existing object
I want to create an animation where one end of a spiral tube (existing object) is attached to a fixed point and the other end is attached to a moving object.
How would I go about doing that in blender?

maybe try with a bendy bone? https://www.youtube.com/watch?v=JS8V4_Ncn0w   ...   https://www.youtube.com/watch?v=WG3PhuzGz_o

@moonboots Thats looks pretty good but is there a way of doing it without changing the shape of the tube (the diameter) when I move it?

there's also the Spline IK, I don't know if it fits better to your needs: https://www.youtube.com/watch?v=Px44mtdLND4&   ...    also you can find tutorials about rigging a spring: https://www.google.fr/search?q=rigg+of+a+spring+blender&oq=rigg+of+a+spring+blender&aqs=chrome..69i57.18335j0j7&sourceid=chrome&ie=UTF-8

There are a few different issues here, and there are a few different solutions.  The not-quite-spoken issue is that with a lot of ways of doing this, you're going to have undesirable deformation on the spring.  Actually making it stretch to another point is trivial.
One way to solve this is to create your spring by running a long cylinder through a curve modifier.  Why?  Because it makes it easy to get good vertex weights on the spring.  Disable the curve modifier on the spring, add two vertex groups ("base" and "spring") and assign all vertices to "base".  Now switch to weight paint mode and draw a linear gradient for "spring" along the length of your cylinder.  Finally, lock "spring" and normalize all.
Now you can re-enable the curve modifier and write it.  You have a mesh that will deform properly with two bones.  Create an armature containing two bones laid end to end along the axis of the spring (named "base" and "spring") and parent your spring mesh to this armature.  Try moving (not scaling) "spring" along the length of the spring and notice your deformation.
Finally, you need appropriate relationships and constraints for your armature.  Parent "spring" to "base" (unconnected.)  Parent "base" or the entire armature to an appropriate object.  Give "base" a damped track to your target object.  Give "spring" a copy position from your target object.  You're done.


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Lighting/material issues when creating a collada model and importing to three.js scene
I'm working in blender to create collada (dae) models which are then imported into a three.js urban scene created by the qgis2threejs plug-in for qgis (open-source GIS software).
I am driving myself crazy trying to match the colors of the collada models and objects rendered by three.js. The following image is an example of this:

In this image are four collada models, set amid a number of polygons created and skinned in three.js. closest to the fore (white) is a model that has no materials attached to it.
Second beyond that (dark red) is a model that has materials attached to it similar to this:

To the left of that is a two-tone model in which I attempted to match the two-tones of the polygons:

The blue/grey building is a similar build, but with emitting ramped to around 30 under the material/shading tab.
None of these were exported with light sources attached (which I realize is probably the issue). The reason I am not including light sources is because that when I do, the new light source washes-out the polygons created by the plugin.
However, why does the unskinned material appear fine, but the others do not? Further, the scene has a built-in light source, why is that not illuminating the materials in a similar manner to the polygons?
And finally, is there a way to export the models with materials to match the polgyons created by three.js? - this is what I'm really after.
Sorry, blender noob.

Related https://blender.stackexchange.com/questions/57531/fbx-export-why-there-are-no-materials-or-textures

Okay, so what I'm trying to do isn't really possible then, or rather should be attempted within the three.js rendering environment if I read that correctly. Good to know I'm not insane.

Might be worth trying glTF-Blender-Exporter and THREE.GLTFLoader. Or consider baking lights and using a shadeless material.

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


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Transferring changes from UV to a mesh
For the sake of example let's say I have a subdivided plane mesh and then I start to edit its UV map by changing vertices positions etc in the UV editor. Is there a way to apply those changes to the mesh geometry itself?
 As in I have a texture and I have changed the vertices positions accordingly so that it all fits perfectly - but I did so in the UV editor and now I want the actual mesh geometry to reproduce those changes and those vertices positions as well (since the mesh is just a plane), is there a way to do so?

Please add a printscreen /screenshots to your question, so everyone else is able to visualize your challenge too

This answer to a previous BSE question might be helpful.

You can do it manually, but it is tedious:

change the plane's 3D origin to the bottom right of the plane, so that all of the planes local coordinates are equal or above 0, like your UV coordinates

now click on each vertex of the plane and in the top part of the Proprieties panel press "Local", change Y to 0 then change X and Z to your UV coordinates

to know which vertex in UV space belongs to which vertex in 3D space , click
"Keep UV and edit mode mesh selection in sync"

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


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How to mirror part of an object but duplicate another part?
I'm making a toy train track switch. There are left and right orientations:

I'd like to be able to only edit one mesh and have it be mirrored to the other orientation (currently using mirror modifier). But the connectors can't be mirrored, they have to keep the same orientation. I've achieved this so far by splitting off the connectors, doing an array modifier, and rotating/translating them into place on the mirror. This is tedious and results in multiple objects, whereas I want to be able to export each switch as a whole (STL file, in this case). I know I can apply all the modifiers, but that negates the benefit of editing both at the same time. Am I missing some best practice here? I'm a relative newbie to Blender.


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Difference between light and emission shader
I got rectangle light source on the right and face with emission shader on the left. Viewport is set to "rendered" mode. As i understand on the right the light is visible, but it's source - is not. On the left - vice versa. How can i get both parameters visible?

You appear to be using the Eevee render engine. Eevee does not support mesh lights. Try changing your render engine to cycles, and they should both cast a light.

For more information on how to do this in eevee, see here: https://blender.stackexchange.com/questions/99631/how-to-make-mesh-lights-work-in-blender-eevee

Right - it's Eevee. Thanks!


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Aligning texture
How to make texture look same scale on side of the cylinder as on it's top?

The texture is  in object space, so it should look the same, with your mapping. Ctrl-A apply the scale of your object. It must have been scaled down in its 'up' direction in Object Mode, so the Object is carrying a non-uniform scale in its transform.  If you scale in Edit mode, you scale the mesh with respect to the object, rather than the object itself.

Ow, i forgot about it...
Thank you)

Further reading: https://blender.stackexchange.com/a/7349/3710

Many things can reduce the side texture distortion.
The easiest thing to try would be to apply scale. (Go to object mode, Object > apply > scale.)
If this doesn't work though, another thing to try would be to select all of the faces in edit mode, and scale it along an axis in the image editor, so that it "undistorts" the texture on the side.
As this would pretty much ruin the effects of the Smart UV project if you are using that to unwrap. It would be a last resort.


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Tiling faces not parallel to axis
I use standart texture from blender. As long as faces of the cube are parallel to axes, it looks fine, but when not - it's like on the image. How can i make the texture on not parallel faces look similar to parallel ones?

This can be done by correctly unwrapping the UVs of the model to fit the geometry:
To start, your shape looks like this:

First, I add a texture coordinate node and a mapping node to my texture (or just select the checker texture and press Control + T to generate it automatically if you have the Node Wrangler addon enabled). You don't actually need the mapping node for this, but it is helpful in many scenarios.
Then, change it so that the UV comes out of the texture coordinate, through the mapping, into the vector input of the checker texture.
Then, using the search feature, select "Smart UV Project" on your object. This will generate UVs to fit your angled edge.
I achieved the following result:


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smoothing cylinder
Is there any way to smoothen cylinder's faces just like subdivision modifier does with sphere?

Shade smooth - is not a solvation, just in case).
Subdivision modifier itself disfigures cylinder.
Subdivision operation in edit mode adds extra faces but doesn't change it's shape (doesn't smoothen it).
Subdividing in edit mode + "Smooth" instrument does better, but it changes cylinder's dimensions.
Increasing amount of vertices while adding cylinder - is a way, but
what if i need some extra smooth after it's already added?

Subdivision modifier and Edge Crease
Subsurf disfigure the cylinder, until you tell him to maintain a sharp edge at the extremities.
Select the edge loops at the extremities, then press Shift+E to enter in Edge Crease mode. Drag your mouse until the edges are perfectly sharp (Edge Crease = 1.0).


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Can't import .obj
I know how to import obj normally. how ever, if you direct your attention to the attached image you will see that the option to import an Obj is not there. I only have Collada and Alembic as an option to import. When I start with a fresh Blender project, no problem I can import the obj, but i want to do it in the file I'm working on. What the hell is going on, can someone please give me advice about this.

Have tried to open the file through File > Open with the Load UI option unchecked?

i had to remove the addon and add it back again

Alejandro Nevárez Lucio is probably right on in his answer.
More specifically, in the Preferences, under "Add-ons", make sure that "Import-Export: Wavefront OBJ Format" is checked. See image.

You can try loading the factory settings under the File menu.
Also you can open a new Blender file then import the object on that new file then copy and paste the imported object.


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Why the scale parameters of this object is 2000 times bigger and there is almost no difference between the two?
I have those two objects that have dimensions that are pretty much the same.
Normally the bigger rectangle should be much more bigger because the scale is 2000 times bigger.
Here is the .blend file : https://www.mediafire.com/file/rjkkx9eby442xm9/support_disques_dur.blend/file

scale doesn't say anything really except the factor from local to global space

That's because the original scale of the object (when you added it) was relative to its first size (scale of an object is relative to its own original size, unlike dimensions).
To reset that scale just press Ctrl+A and click on apply scale, then you will see the object scale is [ 1, 1, 1 ] (unit scale). I hope that helps.


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How to rotate/pan Blender viewport like the Meshlab trackball?
I find rotating with the mouse (middle-click+drag) very unnatural in Blender (2.8).
How can I make it work the same as in Meshlab (which rotates around a track ball)?

There's a setting for that under Main Menu > Edit > Preferences > Navigation Tab > Orbit & Pan choose: Orbit Method: Trackball

Otherwise Blender will constrain you to turntable rotation, which does not allow full free rotation around all axes (it keeps the Z-axis upright while rotating).


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Weird noise when using denoise

i had these weird noise on my render
i had changed render settings even every object material, and it's not solved
Maybe anyone can help?

I think you enabled the Denoicer but use a low amount of samples. you can increase the number of samples. depending what you want

i do enabled the denoising, but it works fine on my other renders.

What is your node setup?

node for what? oh and 1 more thing, if i view on th camera perspective it gets blurry

I don't think this is a materials issue.
I think what's happening is this: you have a low number of samples (it looks like it's definitely below 64). You mentioned you are using a denoiser, which works fine on other renders. However, this scene doesn't have a lot of light, so the signal-to-noise ratio is low, and the denoiser is having a hard time, producing artifacts. The solution would be to increase the number of samples. Using at least 256 might be a good idea:

Another factor that might have increased the amount of noise is that there is little direct lighting - some places need at least 2 bounces for light to reach them. The solution would be to add some more light sources. For example, you could put an emitting plane right behind the window. This would allow light to reach more places.
If this doesn't work for you, please add more information to the question. It's not easy to guess the problem from a single image :) !

ah i see, i use 256 still doesn't work though. then i use 800 and it gets better, and thank you about the light tips it helps a lot. so it gets its weird noise from denoising a lot of noise because my low number of samples huh?

@HiraMuhammad yes, that is correct. This is because there is some randomness involved when simulating light bounces, so there are some calculation errors that can be removed by taking more samples. It's a bit weird that you need 800 samples - I've never seen significant noise at 256 samples. :)


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How to create our own procedural texture like the default ones in blender
I am not talking about mixing different procedural textures .I want to know the process of making procedural textures from scratch. Thanks in advance

You can script your procedural shader with osl https://www.google.it/url?q=https://docs.blender.org/manual/ko/dev/render/cycles/nodes/osl.html

Making procedural textures is all about manipulating coordinates with mathematical functions that produce colors. You'll need to have the following knowledge: https://thebookofshaders.com/
It's more or less easy to recreate those methods in the node editor.

Cycles procedural textures are part of the kernel and can't be easily added to without increasing memory consumption or compilations times, and certainly not without touching the source code and compiling Blender yourself. You don't even mention which textures you want, Internal render, object textures or cycles, but either way this question is too broad and development related

@Secrop Could you make an answer with one example from the link you provided? Some shape or pattern will be nice. What I'm asking is how to 'translate' shaders/functions from there to Cycles Nodes.

@LukeD I could, but that's not the point. Learning how to make procedural textures is not a subject that fits in a 1 question - 1 answer post. There is too much about it. 'Converting' glsl code into nodes is not a light thema also, but most of the functions that exist in glsl, are in nodes.. specially the math node, the vector math, the mixrgb, etc.

Perhaps @user45793 could provide an example of a specific procedural texture they'd like to be able to produce.

@m.ardito This is nice, but the documentation is shady about how to actually tap into the UVW texture coordinates and output a colour. I'm trying to make a shader that could be used for volumetric colour data, but I can't see how can I get the UVW coordinates in the texture shader to produce the colour for that coordinates. Any ideas?

The 'built-in' texture nodes generate their textures mathematically and so most of them can be recreated using Maths nodes - building your own textures is no different.
For example, the Wave Texture can be created by using a Sine function based on the input coordinates :

Or the Checker texture recreated as follows :

Gradient textures follow similar principles - for example, a horizontal gradient :

The Noise, Musgrave, Magic, Brick, Sky textures can similarly be reproduced using maths.
Even something akin to the Voronoi texture can be recreated as detailed in this and this answer.
The Point Density and Image/Environment textures are an exception since those require additional input (the image or point cloud) - although in the case of the Point Density you could theoretically use Combine XYZ or Value nodes to set each of the point coordinates and maths nodes to calculate the proximity to each of those points - but it would quickly become too cumbersome to be practical as the number of points increases.
The 'built-in' textures will always be more efficient that doing these things using maths nodes but they can still be used in combination with each other and additional maths nodes and coordinate manipulation to generate interesting textures.
For further examples, see here and here.


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Attach flat mesh (or curve) to another mesh
Ok, this may be a total noob style question, but all the solutions I've found don't seem to cover this particular type of situation...
I'm creating a number of different types of glass bottles for a graphic design class, some curved, some with flat faces, etc.. (if it makes a difference, I'm using cycles). I have a logo that I created in illustrator (and exported as an svg and png) that I want to attach to the face of the bottles so I can experiment with how it would look both extruded out and cut into the already solidified surface.
So, my question is, how do I take the logo (in any format), and place it (with some level of precision) on the surface of the bottle, following the curve or angle of the face/area I'm placing it, to allow me to experiment with cutting it in (bool or extrude inwards) or pulling it out (again, extrude or bool) to create variations on the appearance. I don't just want to leave it flat (i.e. UV mapping), and don't want to have to overly subsurface to use as a bump map (i would also like to be able to bevel the edges on some variations or make other modifications). Finally, I would like to do it after I apply the solidify to the bottle mesh so that it doesn't affect the inside face of the bottle because I intend to 'fill' them with another mesh to simulate liquid (like the blender guru beer glass tutorial).
Happy to provide images to clarify what I mean if necessary, as well as further explanation of my idea if not totally clear. I just feel like I'm missing something easy here and overcomplicating the process...

A couple of carefully selected or created pictures/diagrams are a very effective way to communicate your problem. You will most likely get better help than what I am able to give.

You could use a displacement modifier with the image texture.
Some examples of this are: Extrude the outside of a cylinder using a grayscale image, Creating a large landscape with accurately varied elevations and Landscape topography from grayscale image,
Given that you want to avoid changing the inside shape of the bottle, this might be useful, because it describes how only one side of the solid can be influenced: How to make a perfectly flat bottom for 3D-printing topographic relief?

If I get you right,
If you want to attach a curve to the glass, you can 1st select the Curve then the bottle and go to edit mode and select "Knife Project" in the Tool Shelf, the curve will create its shape on the bottle (For perfect projection, switch to front or other sides apart from 3D view)
If you want to attach a surface to another surface, you can combile " Lattice Modifier" with "Shrink wrap Constraint"


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how transpose imported key animation?
I have 2 animations of the same object I try to merge in one. the problem is that each start at the same origin XYZ and I need the second one to in the continuity of the first one.
What I did so far is to open the 2nd animation, copy the keyframes from the graph editor, open the first one, go the last keyframes of its animation and paste in the graph editor the keyframes.
When I hit play I see the first animation playing and when the 1st keyframe of the 2nd animation start the object is "teleported" to the origin XYZ.
 I have no clue how to move the 2nd animation without having to redo each keyframe of it which would be a nightmare .
How do I do that?
thank you!

Render both anims and use VSE. Second strip starts where the first one ends. Render it and its done.

Sorry I should have explained that  the goal is to merge both animation to export them after as a fbx not to generate a rendering. I saw that if I switch to pose mode, i can keyframe by keyframe repostion the object to be in the continiuty of the first animation... but there must be a simplier way to select all keyframe and modify the XYZ reference coordinate to transpose it?


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Making an emission shader which does NOT cast light
So i tried gooogling and asking around in discord servers but no one is really helping nor understanding what I need.
To sum it up, I need an object to LOOK like the sun in 3d space, aka it needs to be very bright. "just put an emission shader on it duh!" well there's a problem! I have cell shading and the size of the object depends on how smooth the shadow is! So if I have one light source which is huge, casting a very huge smooth shading all over my cell shaded objects, it just looks weird.
So - a fake glowing object. I just need an object that looks like its glowing but does not cast a shadow. That's all.

https://blender.stackexchange.com/questions/53359/how-do-you-make-an-image-emission-without-washing-out-the-image/

Possible duplicate of Making an Emission shader emit a different colour of light than the colour assigned to the object?

That's easily solved. Find a tab in the emitter's Object Properties called "Cycles Settings".
There's a bunch of things there that you can tell Cycles not to do when it munches through the object. The interesting checkbox in this case is : Diffuse. That tells cycles: ignore diffuse reflection rays for this object.

I didn't even know those exist haha, thank you!

I use this hellish abomination of a beloved monster software since 2000 and I definitely don't know everything. They just keep adding stuff. It never ends.


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Parts of mesh missing after exporting to OBJ
I'm trying to export a model I made to OBJ.
After this I'm opening it with Outfit Studio, a tool to make a NIF file to get it into Skyrim.
Somehow the exported model misses some parts when I open it in Outfit Studio.

I removed double vertices and recalculated normals.
This is how it looks in Blender:

I'm kinda lost, why is this happening?

So I was able to fix it myself, the problem were those huge Ngons created by the Bevel.
This works fine in Blender but seems to be a problem in Outfit Studio/Nifskope.
Now I created faces with 4 vertices like this and it works fine:


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How i can bake the entire cloth simulation to shape keys?
When I give "apply as the shape key" it seems that it only takes a part of the cloth simulation, I want it to take the whole simulation, my cloth simulation has 200 frames and it seems that in the shape key it has only 20

If you do "Apply as Shape Key" it will create a snapshot of the vertex positions from where you are on the timeline as save that as a shape key. The shape key have no animation data. It interpolates from the base shape key to the cloth shape key linearly. That is, if you place the Value on the Cloth shape key on 0.5, each vertex point will be in between the Base and the Cloth.

Thanks man I did not know it was an interpolation, its really helpful


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Blender crashes on start up
I used blender back then and it was working fine. I was using it for weeks and I stopped using it since I got busy. After 3 months, I decided to open blender again but it didn't work. The weird thing is that when my friend copied the file that I have but it was working but mine isn't. I don't know what happened. Also, I had just recently upgraded my ram before I opened blender again.

Does Blender work with the default scene? Are you using the same version of Blender as your friend?

@rob as he said, he copied the same file, so both of them should have the same version! ;)


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How to get a straight bevel on a path?
I want to create a border for a window. The bevel object is a simple shape. The path isn't closed and has an opening at the bottom. Both vertex point has the same values on the x-axis. Also, the scale values are equal. But somehow I don't get a straight extrude. If I convert it to a mesh, the discrepancy stays the same. What's the problem with this?


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How to correctly use vertex colors?
I exported the model into Unity and only the blue faces are shown. I think am doing something wrong, because when I select the blue ones they appear alone, but when I select the red ones both are shown.


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My armatures from blender 2.7 was damaged on blender 2.8
After a hard work, I did a good armature's standard with all IK rules , constraints and restrictions for rotation, etc...
When I open my models on Blender 2.8 I 'have' more bones than 2.7 (like ik.neck_end) and my rules for all bones was lost.
Besides that, in blender 2.7 I recorded my animations in 10 frames, when I see the distribution of frames in Timeline everything is in 5 frames, why ?
Here a example of constrait lost :

Another good example of why you should jump around versions with the same project

Ok, I'll try creating a totally empty file


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Help with add-on to auto save image when I save .blend
I'm trying to write a script that when I save the file (Ctrl + S) save the images on file too.
    bl_info = {
    "name": "Auto-save images",
    "author": "mcunha98",
    "version": (1, 0),
    "blender": (2, 78, 0),
    "location": "",
    "description": "Auto save images datablocks after save .blend",
    "warning": "Works only with external images",
    "wiki_url": "",
    "category": "Paint"}

import bpy

def save_external_images(dummy):
    for img in bpy.data.images:
        img.save()

def register():
    bpy.app.handlers.save_pre.append(save_external_images)

def unregister():
    bpy.app.handlers.save_pre.remove(save_external_images)

if __name__ == "__main__":
    register()

I saw [this thread][1] as reference , but in fact the image not save when I save the file, someone can help me to understand why ?
I don't have any kind of warning or output on console window warning about erros, simply the image file not was save

Can you fix the URL of the thread you're referring to?

is the source of the code above, consider this

The problem is that the handler isn't persistent, so it will be registered when you first register the add-on, but as soon as you open a file it'll be gone again. Annotate it like this to make it work:
@bpy.app.handlers.persistent
def save_external_images(dummy):
    for img in bpy.data.images:
        print('Saving', img.name)
        img.save()

For more info, see the Blender API documentation.

And not is possible define the add-on as a 'startup' or something like that to avoid to call and call again the script to do the auto save ?

If you want code to be executed on every save, it has to run on every save. I'm not sure what you mean.

My goal is when I save the file (Ctrl+S) don't need to go to the image editor and press save (Alt+S) to save the image

Yes, you can create an addon out of your code. As a matter of fact, it already is. Just save it as an external file on your disk, and install it.


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how to separate mesh with armature
I'm trying to separate a mesh with armature animation into two by selecting vertices and press P in edit mode. But the separate mesh is all messed up and does not animate accordingly.
Is there any better and cleaner way to achieve that?

In object mode Alt + P on your mesh or go to Object  > Parent > Clear Parent.

I got it after few tries. Do as the following:

Select your object and goto Edit Mode.
Select vertices or faces you want to split.
Press P and select "By Selection".

The mesh messed up in my case is due to changing action after splitting mesh into 2 objects. Strangely, if you change action while selecting a 3D object, the mesh will go hay-wired. To solve that, be sure you select armature/bones when changing action.


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Not clear water
i'm newbie for using 3D, especially this software. I try to learn from this tutorial https://youtu.be/xSWUa_Rbolk. this is a tutorial to make a water in a glass. but when i render my object something weird appear. did i miss something?
this is a picture and the left side was my render. thank you

did you increase the sample size?

Make sure the bottle has some thickness and the fluid is inside the borders as explained here https://blender.stackexchange.com/questions/35726/fluid-in-a-glass?rq=1]

@sidar and cuoka thank you for your question and answer, from that i realize what happen to my render. so that object surface must not touch each other when apply glass effect. it solve now. cheers!


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Contain mesh within another mesh boundaries?
I'm trying to limit a mesh within certain boundaries so that I can then scale it really big and the mesh never goes out of boundaries of a box.
I've tried using boolean but I get a plethora of strange artifacts. The mask modifier (as I understand it) only accounts same-mesh vertex groups. This wouldn't cut it, since when I scale the mesh I need the box to remain the same size.
I'm trying not to resort to hiding it via compositing, but if that's the only other way, I'll see what I can work around with that.
Do any of you know how can I achieve something like this?
Thanks in advance.

It may be helpful to know the visual result you are seeking for the viewers of your work.  What is the visual result you are seeking? Should the mesh fill the box? A guess would be inflating. At this point IMHO the question is a little vague and difficult to understand.

Scaling is just one way of changing shape. Have you used others? Is there some particular reason you want to use Scaling?

Sorry, I really didn't know how to phrase it properly at the time. Here are pictures.
Small - Big
I attempted using several boxes in boolean mode to mask it out but only one of them appears to work.. for the most part.

If possible your pictures should be in the question itself.  I am not able to understand your problem.  Perhaps you should delete the question and try to rephrase it.  When the reader is guessing the description of  the problem, we have created yet another problem.

Your images should be in the original question.  People should not be able to see images not related to the BSE question.

Please show your work.  Any modifiers and textures and UV Maps.   Still guessing on your goals and your techniques.

A Geometry Nodes group:

... can independently clamp the X,Y and Z coordinates of the modified mesh to a given box-object:

Consider scaling and translating your UV coordinates for a texture producing a displacement.

a simple way is using some kind of alpha / transparency on material level...
here's an example, just to add some other option, this seems to be an old question

The accepted answer is exactly what I was looking for, but this is indeed a neat trick.


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Editing fcurve.keyframe points in FAST mode?
I can add and remove keyframes like this via python, no issues arise.
#remove all existing keys
for i in reversed(range(0, len(fcu.keyframe_points))):
    fcu.keyframe_points.remove(fcu.keyframe_points[i])
#insert the corrected keys
for frame, sample in zip(new_frames, new_samples):
    fcu.keyframe_points.insert(frame, sample)

But I want to use the fast option to avoid updating the fcurve after each modification and only update after the loop:
#remove all existing keys
for i in reversed(range(0, len(fcu.keyframe_points))):
    fcu.keyframe_points.remove(fcu.keyframe_points[i], fast=True)
fcu.update()
#insert the corrected keys
for frame, sample in zip(new_frames, new_samples):
    fcu.keyframe_points.insert(frame, sample, set(("FAST", )))
fcu.update()

Now that code is also functional, but in the dope sheet, the resulting keyframes are dark grey instead of the usual white. Anything I'm missing or is this intended behavior? Does the color have any significance?

This answer doesn't address the FAST mode issue, it is another method to clear an fcurve and set new points that avoids looping, reversing or using  either the insert or remove methods of FCurve.keyframe_points entirely.
import bpy
frames = [1, 9, 20]
samples = [0, 8, 0]
# some action
a = bpy.data.actions["SomeAction"]
fc = a.fcurves[0] # some fcurve
dp, i = fc.data_path, fc.array_index
# clear the fcurve by removing it
a.fcurves.remove(fc)
# new one
fc = a.fcurves.new(dp, index=i)
# new points
fc.keyframe_points.add(count=len(frames))
# populate points
fc.keyframe_points.foreach_set("co", [x for co in zip(frames, samples) for x in co])
# update
fc.update()

Thanks! Ah yes, foreach_set()! I had that in mind but I always find the syntax so unintuitive that I don't come up with it on my own haha

Worked well. Thank you!


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How to transfer an animation from a tree of empties onto an armature (space conversion)?
I'm writing an importer for a game format and everything is fully functional except for the animations, which are still not affecting the skeleton as intended.
Note that the conversion from node to blender bone format is done with the following code, so the bones are reliable and their original matrices can easily
retrieved from the bones:
bone.head = mathutils.Vector((0,0,0))
bone.tail = mathutils.Vector((1,0,0))
bone.transform(node_bind_matrix_worldspace)

Now the animations, I can correctly visualize them as a tree of parented animated empty objects, but I need to transfer these transformations onto an armature.

My assumptions are:
- empty transformations are relative to the parent empty (ie. there is no rest pose; the original, unkeyframed transformation is simply overwritten)
- bone transformations are relative to the bone's own rest pose
- the coordinate axes used by blender bones and my animated empties are different
Which means that to get from the empty object transformations to a bone transformations, I think I have to do two things:
- remove the rest pose from the transformations
- change the coordinate system (the blender bones point in Y-direction, while the empties point in X-direction)
My keyframes are stored in 4x4 matrices called key_mat. To remove the rest pose from the transformations, I do:
key_mat = key_mat * node_rest_mat.inverted()

(I've also tried the "commute", ie. key_mat = node_rest_mat.inverted() * key_mat)
To change the coordinate system, I do the following and it seems to work on the tree of empties:
matrix_swap = mathutils.Euler((math.radians(90), 0,
math.radians(90))).to_matrix().to_4x4().inverted()
#...
key_mat = matrix_swap.inverted() * key_mat * matrix_swap

I have also tried axis_conversion(...) from bpy_extras.io_utils but could not get the same result.
The result has the Y axis pointing forward as intended, and is globally rotated as well. Local animations are preserved, so it should be good.
If I do the steps as described above and put everything together, I'm getting a distorted skeletal animation but not the desired result:

I just can't seem to produce code that puts those two together into something that creates equivalent animations on the skeleton.
Any ideas on how to correctly transfer the keyframes from these empties onto the bones?

Have a look at answers relating to c3d import  If you have a rig I'd suggest using the constraints model outlined by JerryNo.

Thanks, but ideally I want to advoid copying and baking the transformation from the empties (which are just a visualization of the problem) to keep the script running at reasonable speed. There surely must be some way to transform the transformations with matrix math. It's just so complicated haha

Blender includes an addon called "Motion Capture Tools", it should do that for you, or show you how to do it.

@batFINGER yes still enables in 2.79 release for me.

Looks good, walking forward now.Can you post a sample file?

Will do soon once code is cleaned up a bit and I've tried a few more things. ;) Also thinking about portin this replacement of the old matrix code to python...

I've successfully ported the improved the new C matrix import code to python! Not sure if it really helps in this particular issue but it might help others.

All done, see answer below for code if you're interested! :D

Nice one. Not using windows

Now I got it!

Bones are calculated using this code. Then the rotations are corrected locally, and finally the bones are rotated into the desired spot as if you rotated the whole skeleton in object mode and applied the rotation.
Overview:
#first create the matrices to correct the transformations
matrix_swap = mathutils.Euler((math.radians(90), 0, math.radians(90))).to_matrix().to_4x4()
rotateback = mathutils.Euler((math.radians(-90), math.radians(-90), 0)).to_matrix().to_4x4()

#create and pose the bone
bind = matrix_swap * bind * matrix_swap.inverted()
tail, roll = mat3_to_vec_roll(bind.to_3x3())
bone.head = bind.to_translation()
bone.tail = tail + bone.head
bone.roll = roll
bone.transform(rotateback)

#bring the keyframe into the right space
#we must make this matrix relative to the rest pose to conform with how blender bones work
key_matrix = fallback_matrix[bone_name].inverted() * key_matrix
key_matrix =  matrix_swap * key_matrix *matrix_swap.inverted()

The complete importer code is available on github.
Below is my original answer:

Not really an ideal solution, but at least progress.

This brings the keyframe from relative to the parent space into relative to the bone's own rest pose space:
key_mat = node_rest_mat.inverted() * key_mat

The keyframe would then work on the bone if the bone was oriented like the empty.
So I tried to orient the bones like the empties, ie. give them the same local orientation. I could not get it to work with the following 'reliable' bone creation code that I'd like to use:
 bone.head = mathutils.Vector((0,0,0))
 bone.tail = mathutils.Vector((1,0,0))
 bone.transform(node_bind_matrix_worldspace)

Probably I was doing wrong matrix math with the bones... Instead I had to resort to this answer. I have used that in previous scripts but discarded it in favor of the above code, as manually calculating head, tail and roll tends to mess up the roll on some bones.
I will keep at it and see if I can do it with a nicely aligned skeleton...


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Setting custom normals without customdata_custom_splitnormals_add() operator?
I'm trying to make my scripts more low-level and less operator-dependent. One thing that I haven't been able to figure out is this one:
me.use_auto_smooth = True
bpy.ops.mesh.customdata_custom_splitnormals_add()
me.normals_split_custom_set(no_array)

Is there any way to do it without the operator? If so, what's the corresponding low-level code?

do you actually want to use custom_split_normals?
i'm using it like this: https://github.com/Aadjou/blender-scripts/blob/master/utils_split_normals.py

Yup, I want to set them on a model that had none before. I always thought I first have to create the data layers as from the GUI, hence the operator customdata_custom_splitnormals_add(). Will try your code!

i was mostly wondering what you want to do with the split normals, because it's super badly supported by blender and you are not able to work with your data much more, i'd avoid it unless you are writing an exporter, in that case you can have a look at this example / line:
https://github.com/archilogic-com/data3d-blender-io/blob/a5de9ae9ec7b25f00496d8ca120cabec877709f2/io_scene_data3d/export_data3d.py#L230

Indeed, it is for an importer / exporter combination. The thing is, with the current blender, it seems to work without the operator and even without me.calc_normals_split(). I'm not sure why, but I remember it was not working without the operator in 2.70-ish...

Turns out you don't need the operator at all and I was getting funky results because I had a remove_doubles operation further down the pipeline.
Working example code:
no_array = []
for face in me.polygons:
    for vertex_index in face.vertices:
        no_array.append(mesh_verts[vertex_index][3:6])
    face.use_smooth = True
if use_custom_normals:
    me.use_auto_smooth = True
    me.normals_split_custom_set(no_array)


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How to create a button for wind in Blender
For a 3D Winter Snow Simulation I'm working on in Blender for one of my college classes, I am required to create a button that causes wind to shift falling snow in a different direction. The following is what the instructor is looking for:

The environment should have a Wind Wheel, such as pressing a button it starts or stops. Every time the wind wheel is turned on, the snow keeps falling and it is affect by the wind when it gets close to the wind wheel. For sake of simplicity, consider that the entire snow is affect once on the same high of the wind wheel, if the wind wheel is active.

Please tell me what I can do to accomplish this.

You have to do your own homework.

Homework sounds much more interesting than it was in my day.

I would go with drivers for the relation button ↔ snow, with and force fields for the wind effect. Create your button object, and make it drive the properties of your wind.


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How do I change the orientation/anchor point of a group?
Im new to blender and I created this group and instead of rotating around the middle of the object, it rotates around some other point and the point moves when I move the object. How can I change the pivot point to the centre of the group?

I am suggesting you change the word group to Blender Mesh Object in your writing above.  Group has a different meaning in Blender involving many objects.

In edit mode .. not object mode ... move your mesh relative to the origin for an improvement.
or
in object mode use the menus in the image below.  Object/Transform

Origin to Geometry
For precise control click on part of your mesh to move the 3D Cursor then use the menu option
Origin to 3D Cursor.
Try the similar menu options.
Also I believe you are talking about a Blender Mesh Object and Not a Blender Group.


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Basic fluid - inflow too small to generate fluid or generated fluid too thick
I'm setting up a fluid simulation, and it seems like inflow is too small to generate any fluid, or generated fluid too thick(too much).
This is the setting of the simulation:
Inflow
Volume Initialization: Shell
Export Animated Mesh: Checked
Inflow Velocity: Y -200
Domain
Final Resolution: 200
Preview: 100
Time Start: 0
End: 32
Speed: 1
Outflow (2 outflows)
Export Animated Mesh: Unchecked
Scene gravity: Y -2, Z -9.8
https://www.dropbox.com/s/3i7j83qifddrfnt/water_simul_new.blend?dl=0
I'm making a simulation of about 32 seconds, and I'd like to make fluid to wave slowly through y-axis.
I found out inflow object is too small to generate anything(no fluid at all or fluid stuck in outflow object) or generates too much fluid after I scale up the object (scale applied well).
Settings are always mostly similar. I'm only controlling inflow object's scale or Final Resolution.
Is there any way I can make small fluid coming forward from far away? Right now the blend file shows too many fluids.
Thank you!

the blend file doesn't work, i believe you can upload directly

Setting your y-axis inflow to -200 is a substantially large number for fluid physics. Try something like 2 or 3, because large numbers cannot be calculated, and don't show up. This is probably why your simulation is failing.


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Height Map: how to deleted unwanted faces?
SupFolks!
I applied a height map to a plane and was wondering if there's an easier way that I can delete faces circle in red w/o doing it by hand.
Thanks in advance.

Heightmap

Unwanted faces circled in red

Did you try going to a side Ortho view and selecting all the vertices at z=0?

So I hit Numpad 5>3, but I don't know how to select vertices on particular axis.

I don't know if there's a way to say "select all at this axis." I just meant from that side view, use the 'B' key and draw the select rectangle around close to the axis.

If I select edges, it works! Thank you so much!

for 2.79 :in Edit Mode, hit numpad 5 to go to ortho view and hit either numpad 1 or 3 to get to perfect sideview then hit CTRL+tab and hit E to make Edge Selection then hit B to start the box selection tool hit X and select faces to deleted unwanted faces


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No matter how many lights or suns I add, this shiny model stays dark
Very new to blender, first time question.  I could not find a similar problem searching existing answers.
I have a rendering, and no matter how many lights or suns I add, this model stays dark.  That's a light colored wood texture that appears dark.
This is an imported STL file.  It seems like no matter how many lights I add, it stays the same amount of dark.  You can see my settings in the next photo.  I have a sun, a point light, and spot light all by the model, but no difference weather I turn them on or off.
Thank you for any help.

Could you share your .blend file?

Wild stab in the dark:
I think you only have mostly reflecting materials in the scene. They act as mirrors and mirrors are only as bright as the stuff they can reflect. You don't have anything bright in your scene to reflect. Just for fun, add a few big planes with diffuse shaders into the scene that are sufficiently lit and see if there's a difference. Alternatively you could crank up the brightness of the world color which, right now, is what gets reflected.
Your lamps seem to work fine since the small areas where they reflect into the camera are burnt white. Problem with mirrors is that they only show the light when the lamp is on the other side of the mirror with matching angles so that it can reflect into the camera. think of where the sun is on a sunset at the beach.
Another way is to use a mix shader (glossy/diffuse). That'll help directing much more light into the camera.


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fluid dynamic helix
I trying fluid simulator in Blender, and I wanted to make an animation where water flows from centre along to curve and screw along.
How setup Inflow for this result:

marked as duplicate by LukeD, Ray Mairlot, Duarte Farrajota Ramos, David :( but I can't find answer for my question. May be you can link to original?


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Hair not pointing with normals

Does anybody know why the hair is acting this way? if i make a sphere the hair follows the normals. But not with the head of the bear, normals are ok and pointing away from faces

There's really nothing we can do for you unless you attatch a blend file. Try to use this website: https://blend-exchange.giantcowfilms.com/

Thanks for the reply, I already figured it out. I exported it with a wrong scale from C4D.


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Set exclude on collection in multiple viewlayers
I'm trying save the values of the exclude property from all the collections in every viewlayer(I have multiple viewlayers).
I'm trying to save my current state, so I can re-apply later. I'm saving it in a list written to a .Json files with this format [viewlayerName, collectionnName, exclude] the data types are string, string, bool.
I have a hard time finding a way to set the property back. Does anyone have an idea how I can set the exclude value based on the view_layer and the collection_name?


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Library override collection using python
Hi maybe someone can help me figure out how to script this, how do a make a library override of a collection using python. I have figured out how to do it on a single object bpy.ops.outliner.id_operation(type='OVERRIDE_LIBRARY_CREATE_HIERARCHY')
But I would like to simply give a collection object or name as input and then make the library override the contents of the collection. Just as this action.

maybe this helps: https://blender.stackexchange.com/a/177657/16634

Using this code is te solution to the problem:
import bpy

for obj in bpy.context.selected_objects:
    bpy.context.view_layer.objects.active = obj
    bpy.ops.object.make_override_library()


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Load data to cloth simulation setting
I want to write a program that can write a json file that record values for cloth simulation setting and read the json file.
For example, when I finish a good cloth simulation, I can export a json file that contains all the values assigned in quality, mass, air and sprint etc.
Or when I load the json file, blender assign 3 to air_damping in ClothSettings if "air_damping":3 is read. If there is no "mass" key in the json, blender use the default mass value or the assigned value in blender.

OK, I am silly.... setattr(settings, "mass", 0.5) makes it......

If settings is a blender ClothSettings instance could also use settings.mass = 0.5 ... which is IMO more readable, I'd use set attribute when you have key, value pairs  setattr(settings, key, value)


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Hybrid rendering bug?
While using the official Blender 2.81 release for the first time (the last time I used Blender 2.81, it was still in Beta) I encountered a strange phenomenon while hybrid rendering in Cycles.
If I start a render with only my CPU enabled as a CUDA device my Ryzen 3600 chews through the 8100 tiles in about 3 minutes.

However if I additionally enable my GTX 970 and use both in hybrid mode my CPU seems to stand still not finishing a single tile.

The remaining time of 0.08 seconds is frozen as well, indicating that something is going horribly wrong. My system monitor is showing 100% CPU utilization, which is even more confusing to me. What is my CPU doing the entire time?
I have to mention, that I'm using Manjaro Linux and the AMD Catalyst driver-package has been discontinued recently, although that should only affect graphics cards not CPUs and my CPU has been rendering just fine on it's own.
Does anyone know how to fix this issue?

Well, I just found out that this bug only occurs in the version of Blender that you get from the Manjaro repository. The binary from the official website seems to work fine. So I guess, I'll head over to a Manjaro forum and tell them about this...

I know, but I personally like to get all my software via pacman/trizen if possible, because it means virtually no maintenance work for me. And if I don't install via this method, KDE won't show Blender under my list of applications.