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How to inherit material when using geometry nodes?
I'm trying to figure out how to get GN to use the input geometry's material, and... I just can't get it to work.
Here's a really simple setup:

(I'm using the default scene, but using this with any mesh shows the problem. Just set the object's material to something that's clearly distinguishable from the default. Toggling display of the GN modifier makes it clear that the material is set on the unmodified object but not the GN-produced mesh.)
What changes need to be made to this setup to get the GN output to use the input object's material?
(Note: this is somewhat overly simplified. Ultimately, I would like something that works on curve objects sans the Mesh to Curve node. However, as I only need it to work on line segments, I was hoping that using mesh edges instead of curves might work better. Alas, no such luck.)

Add a Set Material node after the Curve to Mesh one and click on the Material field to select the material?

@JohnEason, I want to use the material set on the input geometry... not have to specify a material separately via the GN modifier.

I'm not that familiar with GN, but I'm surprised that the Object Info node doesn't have a material output that could be used. I suppose that would be a problem if there's more than one material on it though.

@JohnEason, me too! There really ought to be such a node (probably one that takes a geometry and a material index and spits out a material).

You can make such a node using existing tools

@MarkusvonBroady, how? The only node I see that outputs a material is the one that takes it from an input constant/port. Please consider explaining in an Answer.

You can't output a material but you can set it on geometry by joining and setting mat index

(Using Blender 4.2.4)
The default material (with index 0) can be transferred to mesh generated inside a GeometryNodes modifier by joining the generated geometry and the input geometry (see dark pink nodes), that can be deleted after if needed (see dark blue nodes). The input geometry must be the first input of the Join Geometry node.

Resources:

Blender file (4.2.4+):
About GN modifier attached to curves, see Use material assigned to curve in geometry nodes.

Argh... I want to break something now. One of the reasons (I suspect) I couldn't get this to work is because when I converted my curves to mesh, Blender removes the material.  AFAICT there's still no way to accomplish this with curves, however.

With curves, one workaround (not very satisfactory however) is to input the material through the Group Input node to use it with a Set Material node. It just means that the material "name" is not hard coded inside the GN graph, but it is not really inherited.


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Make a 3d line on Object
i wantd to make a "line" around the model. The only solution i found is to select the edges for the line and press "s" to put them more into the model. But then i need to select every single edge left and right on that "line" to put them more together to get that "deep" effect. Is there an easier solution to do that? It does not only take alot of time to select and move every edge the bigger problem is that the edges arent all at the same spot to have a smove line.

https://blender.meta.stackexchange.com/questions/1080/add-images-to-stack-exchange-questions

could you make another screenshot or draw something to make it clearer please?

Perhaps you could use smoothing an edgeloop and the shrink/fatten tool (Alt S).

I did edited my post with more pictures, maybe its more clear now @moonboots

If what you want to do is what Nicola Sap shows, here is another way to do it, pretty close, but with the Bevel tool:

If your edge loop is clean (i.e. you can go around your "ring" by walking only along quadrilateral faces) you can use loop cuts:

CtrlR, find the correct area (pink line), LMB to accept the region, Enter to accept the position

(this creates the line that will be then "buried")
Same as before, to the right and to the left of the middle line. This time, though, slide the "line preview" to make it closer to the centre line before accepting (Enter)

(Alternatively you can AltRMB select the middle line then CtrlShiftR to make two lines around it)
deselect all (A), then AltRMB to select the middle line, and finally S to scale it inwards

P.S. instead of making 3 cuts and shrinking the middle one, you can also make 2 cuts and shrink (E then AltS) the faces between them. I personally suggest this method.

source: Stack Exchange

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

sort: votes


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Motion blur makes whole scene completely blurred
I followed a tutorial from "Blender Made Easy" of a stormy ocean scene https://www.youtube.com/watch?v=oysCSbhXYBo&t=2s&ab_channel=BlenderMadeEasy
When I render the animation, the motion blur makes the whole scene blurred. Majority of the 400frame render looks like this
The camera has a location constraint to a plane shrinkwrapped to the ocean surface. When I render without motion blur it looks fine but not as realistic. I have tried fiddling with the motion blur settings, changing it from centre on frame to start or end onframe but the result is the same as if there was no motion blur applied. Here is the settings for motion blur that I've used

Any help would be much appriciated! here is the full clip https://drive.google.com/file/d/1jdGnZiX166iwy-Oq-9xyoRhbJ6UATuft/view?usp=sharing

Can you show your complete rendered output?

Updated with a link to the clip at the end of the post :) Thanks

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


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Render Failure - Image is smokey

I am new to using blender and I am working on rendering a scene that uses portal lighting, but I am having some render issues and I don't know why. Is there anything I can try to fix this issue?
Denoising didn't seem to make a difference on the picture cloudiness one way or another. Adding more samples helped a lot, but I still have that issue some.
Here's a link to my blender file https://drive.google.com/file/d/1uNfl7msr-o_v0AR5WSfbMFfdvP_zo2Ly/view?usp=sharing
Thanks everyone, the advice was very helpful! For anyone else having this problem, try the advice below and primarily lower the number of your light sources in the scene.

Looks like denoising or clamping to me

Try increasing the samples

Thanks for the feedback! Sampling helped some, but it didn't fix the problem. What else could I try?

Hi Trent, could You provide us a .blend file please?

Heres a google drive link to the file https://drive.google.com/file/d/1uNfl7msr-o_v0AR5WSfbMFfdvP_zo2Ly/view?usp=sharing

first of all, in the archive you've sent i haven't found any portals.. to set them properly you shoud get an area lamp and not a sun one.
like this:
second, i recommend you to reduce the light bounces, its better for performance and i think it may help with some of the noise:

the denoiser effect may be too strong, i'd leave it in the default settings, besides 8 radius costs a lot of performance..
A big part of the problem can be because there is too many light sources.. i don't know how you could fix this.. but from what i already said im pretty sure you'll get better results

Thank you. I forgot I changed my portals to sun lights. I thought the portals were the issue at first.
Ill definitely try what you suggested. I also change my material properties and that has helped too.


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No flame in Blender Render
I am creating a simple animation with flame. I followed a tutorial and flame appears in viewport but is not present when creating an animation or image. I am using Blender Render (not Cycles and GPU which seems to be a common problem). What seems to be my issue?

please delete your old duplicate question: http://blender.stackexchange.com/questions/45979/no-flames-when-rendering and keep this one, it's better.

Sorry, I cannot delete it, I posted it as guest.

The problem is with mapping the domain materials textures, this is how it should be:

Set both your Smoke and Fire textures like this. The domain object is Cube.003 and not Icosphere and the mapping is Generated.

Thank you, it works now. I thought you had to set the material to the iconsphere as the fire should be coming out of it. It works now that I set it to the domain.

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


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Why is my rendered animation different to what I see in the 3D view?
I’m fairly new to Blender, although I’ve managed to put together some simple animations.
I’ve made a simple ‘fruit machine’ with three wheels. Everything plays as expected in the 3D view, but when I render (whether to a sequence of .png images, or to a video) I’m getting a different result. The animation lasts for 600 frames. Everything starts off fine, but at frame 450 (for example) the rendered image is different (in the way that the second wheel is rotated) from what I see in the 3d view when I scrub the timeline.
In the 3d view, I have ‘render only’ set in the display menu.
Is there something obvious I should be checking? I can post the .blend, if someone would take a look.
(Cycles, in v2.77)

blend file is here:

You have two UVMaps on the object where the fruits are mapped to. See this screenshot:

At the moment in the UV Maps section, UVMap_wheel02 is selected, and gets displayed in the viewport. But the other map, UVMap_wheel01, is set to be the renderable one (the camera icon behind the map indicates that). That means, if you don't manually override the UV map to be used, Cycles will pick the one which is marked as renderable, so the first one in your case. If you select the first UVMap in the editor, you see this in the viewport:

If you want to use more than one UVMap in Cycles, you can use the dedicated UVMap node to grab a map by name:

Or alternatively you can mark the UVMap_wheel02 as renderable by clicking on its camera icon in the UV Maps section.

Brilliant - Thank You for such a clear answer, which has totally solved my problem.
Believe it or not, this is the most complex thing I’ve done in Blender. Learned a lot from it, that’s for sure. Long road, but fun. :-)
I really appreciate you taking the trouble to help this noob. Special Thanks for the screenshots.
Thank You again. Very much appreciated.

@user3849061 Glad to help! Keep up the nice work!

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


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The problem with the density of smoke in the simulation
I have a scene with fire and smoke simulation.
I have changed the parameters of gravity to make fire and smoke tending down to the ground (it will be a fiery trail of soaring object).
Below there is a plane-obstacle for the fire and smoke, so the smoke should be spread over the surface.
However, for some reason, somewhere in the middle of the simulation, instead of a thick cloud of smoke, I see a very small amount of smoke along the surface, which spreads not evenly over it.

What could be the reason, and how can I fix it? Screenshots with the settings are below.

P.S. The lighting in the scene is not very good, that's why the smoke looks black, and the topology of the fire emitter is not the best, but I think this is not the reason...
P.S.P.S. I tried to increase the dissolve time, but after the first big bunch of smoke, smoke density decreases again. Also, I do not understand why the smoke spreads over the surface so uneven:

Blend file:

@cegaton Yes, I attached it to the post, thank you!


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Recursive Particle system
I have a blue Suzanne. On that it should emit red balls. And on each red ball it should emit green box.

I have tried with Is it possible to recursively instance object particles?
But it does not really answer the question nor work and also does not work on animated objects. Or I am wrong in sequence.
No green boxes available in result:

Download current file: https://onedrive.live.com/redir?resid=AD9FE0A4134005AA!2480433&authkey=!ALz-h9Vlfrbekfs&ithint=file%2cblend

Answer is actually quite simple: this cannot work in current design - to simplify, objects as particles are not actual objects, but instances of objects, with quite limited sub-set of objects features. An instance cannot emit particles.


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Additive Emission in Cycles
Question is how to create additive shader.
If you need particles which just "add" light to a scene. Not render a surface but create emission.
If color changes from yellow to red for example, the red area of model does over-draw the yellow area (object behind) in case the emission does not understand to just add / increase color factor.

My project: Download Blend File (sorry, stackexchange responded with upload error)
How to math "add" color in cycles?

Like Halo in Blender Render.

Is your goal to light up some other object not shown in the image?  Is your goal to create a glow?  Or something else? Can you place an image in the question that shows your goal?  Your second paragraph is difficult to read IMHO IIHO.

Goal is to have the image like in picture 2 (additive) and picture 3 (Add=1).

I'm thinking adding (not mixing) a transparent shader to the emission shader should do what you are after.  I'll have to give it a try.

The way to do this is to add a transparent shader to the emission shader.  This means that the surface will emit light and allow light to pass through it, so further emission materials behind it will add to the brightness.

Adding some randomized color produces this result.  Note how the overlapping portions do indeed add up brightness as desired.

Thanks!  This is the best answer about additive blending I found.  Where is the idea of "Add Shader" come from? How do you know that the RGB of "Emission" will be simply added to the ray trace's RGB value? Where did you learn these knowledge from?  Official document doesn't have much detail.

If what you're saying is true and you just want the particles to light the scene but not to be lit then you would simply use the is camera ray socket of the light path node to make the particle transparent for the camera while still contributing light to the scene. Another way of doing it would be to go to the cycles settings in the object tab of the properties pane and disabling ray visibility for the camera.
However, in order for light to be visible, it has to be reflected off a surface. So if you only have particles in your scene that only add light but do not reflect light, then you'll end up with a black picture.
Having said that, if you want your particles to render the light they emit but not to block off the light of other particles in the back, then I would suggest to use an add shader node to combine the emission shader with a translucent shader set to pure white. This way the material has both properties translucent and emit.

Thank you for the answer. But it does not look like expected. I uploaded the modified blender file. I also uploaded my original file in my question. When I add the add shader to it, it looks extreme red. If I remove the source color from refraction node, it looks white (without red). It is no RGB addition. http://www.goldengel.ch/temp/Writer_stackexchange2.zip

maybe if you use transparent instead of translucent (but keep the color white). I don't know the exact look you're after, but this should give you a basic idea of how you could approach it.

At the end I understand and you was already correct with your answer. I just did not understand the explanation. Now I do. Thank you.


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Take object color of underlying Emitter
What to setup if the emitter should take the objects based on the color where it comes out?
Sample: Icosphere should take the color of where it emits on cube.

There is one solution for images. How to setup this with color ramp?

You can do it in a similar way as described in the linked answer.
Just copy your material node setup from the cube to the icosphere, change the coordinate type from Generated to Object and choose the cube object from the list.


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cycles transparency results in color loss when background is black?
to make exactly clear what i want:
i want to use a scripted animation that uses live motion capture data for projection mapping.
it shall look like some sort of energy beams or electricity going out or into the body of the actor.
for that i rendered a set of png's that use alpha which i added as an image strip to make an animated texture with animall.
so far so good, everything is working.. with one exception.
wanting to do stuff live, i obviously don't want continuous rendering resulting in a mess of noise, so i thought - let's do it in material viewport shading in cycles
i added a node setup for transparency, which works fine in rendered mode.
but to ensure that i can use tranparency in material viewport shading, i switched to internal, adjusted transparency settings and switched back to cycles.
my problem: this results in transparent mesh, but the color of my texture is gone.
why is this and how can i prevent it?
blend file:

i took a second look at the background plane and i noticed that the loss of color appears when the plane's material color is set to black. when it's white, the texture appears blue, although it's hard to see. my goal is to achieve transparent mesh with a texture fading to alpha in viewport material mode, that keeps the blue color no matter what background plane there is. having to use a white background makes transparency obsolete in my case.
why is this happening?
is there a workaround? (like really fast live rendering without noise that doesn't look too bad?)

Short answer
It won't work. Your technique has a fundamental problem that I'll explain below, but even if your technique was correct, some limitations of Blender's viewport will make impossible to produce the correct result.

Long Answer
Why the method you used wont work:
You say you used pre-rendered PNGs as source, and that's the problem.
PNGs use unassociated (often called "straight" alpha), which is inappropriate for compositing light effects.
The explanation is rather simple: A lighting effect, such as fire, electricity arcs, laser beams, etc.) is a purely emissive phenomenom, so itt's basically an addition (the light source adds luminosity but doesn't occlude any of the background).
When you use an unassociated alpha image (like your PNGs) every pixel with alpha > 0 will occlude the light coming from the background.
The phenomenom you're trying to reproduce shouldn't occlude any light from the background, so its alpha has to be 0.
But in unassociated alpha images, there is no RGB information where alpha is equal to zero, as that information is discarded by the alpha over operation for unassociated.
What you need is an associated image (often called "premultiplied), that lets you have RGB where alpha is equal to zero for this kind of effects, that need pixels that are luminous but don't occlude the background at all.
For that reason, PNG won't cut it.
The proper way to composite luminous effects:
If you use instead EXR images you'll be able to produce lighting effects that can be mixed with the alpha over operation as if they were a pure addition.
Just render your lighting effects on black, use a "set alpha" node to assign a 0 value (black) to the alpha channel and save as EXR, and you'll have some nice lighting effects ready to be composited.
Why it won't work anyway:
Blender's viewport, and to some extent cycles have some limitations regarding alpha manipulation.
The materials view does some funny things flipping between associated and unassociated alpha, which results in RGB with alpha zero being lost before it gets to your screen
So, even if you try to produce the right shader with cycles (which could work in the compositor), the material view will kill it.
Your best bet is cycles with a good GPU that can keep up the pace needed for realtime preview.
Since the phenomenom is purely emissive, you need an emit shader which is extremely fast to render, and the good news is that you need a few samples to get it rendered. Noise shouldn't be a problem (just use 8 for start resolution and one sample for preview, it will be fast and noise free).
The bad news is that cycles has some problems producing a proper output from a shader constructed with an alpha-driven mix where pixels have to be luminous, so you can connect the nodes in cycles to produce a luminous premultiplied image, but it won't render correctly.
But wait, there's hope! :-)
Not everything is lost: If your ligthing effects are purely emissive and you don't need any occlusion (which means, all your alpha will be zero), you can create the effect with cycles.
First you have to create an emission shader using the ligthing effects rendered on black background as texture, then you need to ADD that shader to a transparent shader using the add shader node.
The output will work in the cycles render view and it will be fast.
It won't work in the materials view, though. It will render white.

I'm going to try this out the next time i'm on my pc, but your answer sounds very promising. thank you, that gives me some hope, as emission is what i wanted to do in the first place, but thought it won't be fast enough in rendered view. that opens the possibility for way better results, as long as it is somewhat smooth and if not, i'm going to get a new gpu someday anyways. great answer, thanks for your efforts!

What you are saying is correct, but you have to keep in mind that when viewing in material view, cycles doesn't account for the light put off by emissive materials. This makes achieving that effect through viewport impossible, no matter which kind of image you use. However, she only asked for why her solution worked, and consequently, in her blend file was using a diffuse material, so I assumed she didn't want it to put off light. If you want the light to be put off onto the objects of the film strip (properly) she would have to recreate the person with a mesh for the light to hit.

Uncle Snail:

e-proxy's solution didn't really work, it only masked the problem.

Showing the result in the viewer isn't technically impossible. It's impossible in Blender because it's not dealing with alpha channel properly.

Saying that the viewer doesn't account for the light put off by emissive materials is inaccurate. There's no difference between light emitted by a light source or bounced by a surface for the camera. If it's a pixel it represents light emission.

This answer may help just for reference purposes, but all of it's contents may not be accurate. So read on if you want.
That is just an illusion created by light. It looks like there's less light because darker colors appear less saturated than lighter colors. That is why it looks like the color is drained.
The reason your solution works is also quite simple. The Blender viewport does not render accurately. If you change the transparency color to black, then press render, it will not be transparent at all. The transparent parts will be black.
Why does this matter? In the viewport, the transparency shader is counted as transparent, and looks transparent, no matter what color it is. However, when there is part transparency, where the transparency is fading out (like on your glow), the render in the viewport will not appear transparent at all. (but instead appear black, like it should, before cutting off entirely.) Now remember, as the glow fades out we get more transparency, NOT less color!
This means that when there is part transparency in the viewport, Blender calculates whether it should be transparent, and because of the black color, decides it shouldn't. This makes the color appear in full again, because the transparency was fading out, not the color. Therefor, if the color is set to black, in the viewport it will appear the same over black and white, but rendered, it will not.
You will still have transparency in parts of you image, but no matter what surface it's on, it will look the same, because it is surrounded by a black outline (even on a white surface), and does not fade out, leaving full saturation color.
I hope you understood that, but I sounded a little confusing, so below are some illustrations.
On top, we see how a white or black background can change the appearance of colors (which is explained by many reasons), and on the bottom, we see a comparison of a Blender viewport render when transparency is set to black, compared to white. Note that in the first image, it is all eye illusion, and all rendering an colors are correct. In the second image, note how the edges of transparency don't appear transparent, but black.

Hope this makes sense. Thanks.

thanks a million! i didn't knew how to deal with this for the past days and it made me mad. you served a perfect answer that is easy to understand and very visual, so thank you for your time and efforts, sir!

This is incorrect. Lightning effects are purely emissive phenomena, and the model of occlussion/emission of alpha compositing can only work properly if there's no occlussion at all.
Emission with no occlussion is impossible with associated alpha images (PNGs are), hence it's impossible to produce correct lighting effects from a PNG texture. Read my answer for more information.

Sorry, I meant "it's impossible with unassociated alpha images (PNGs are)". Associated is the way to go.

I'm not an "expert" in any way, but in this case, I think, because when alpha is <0, there is no emission (mix shader is all toward transparent) the color data from the image will not need to be used, which means premultiplication should not be necessary. Is it needed because of something to do with the viewport?

No. It depends on the alpha format:
Unassociated (Straight) alpha foreground will be pre-multiplied by the alpha-over operation, resulting in no RGB where alpha is zero.
On the other hand, Associated (premultiplied) alpha doesn't get pre-multiplied by the operation (it already is), so it's only an addition over the occluded background.
If the viewport dealt with associated alpha properly, you'd get a proper compositing of lighting effects with associated-alpha images (the one true emission/occlussion model)

Realtime OpenGL Composition in VSE
Maybe this solution is also interesting for you:
As others pointed it's difficult to compose transparency in the 3D OpenGl viewport. So why not split your two elements in two scenes and composit them together with light-add-mode in blenders video sequence editor? VSE even plays back in realtime when in OpenGL-Preview Mode.

So here is how to do it:

Split your two elements (flash-effect and bg-plane) in two different blender scenes
Link camera between the scenes, so they share the same animation
In both scenes set "Render-> Open GL Render Options -> Alpha Mode" to transparent
Create a third scene for compositing and switch to Video-Editing Workspace (VSE)
Add new Scene strip and select Background-Plane Scene
Add new Scene strip on top and select your flash-effect Scene
Set the Blend-Mode of this strip to Add for additive color mixing
In VSE-Preview-Side-Panel make sure OpenGL Preview is checked and set to "Material"
You now have a realtime opengl preview of the two composed opengl-rendered scenes
instead of clicking the cycles Render "Animation" button click the little clapperboard icon in VSE, which says "OpenGL-Render Active Viewport"
If you want you can add other Strip Modifiers, or Effect Strips to correct color/contrast etc.

So maybe this helps!
Cheers,
Anton

i wouldn't have ever thought of this

If anyone has the same problem:
-> set the color of the transparency shader node from white to black !!
now it works

bounty is for anyone, who can explain me why exactly this is, how it works


text:
why does the Shader Which I created gets purple when I add another image texture to the randomizer?
HYi,
I have a decent amount of Tv screens in the scene for which I have created a shader. Also I randomized the image texture inputs to display different videos on them. So, as you can see in the pictures there is a node group which I have shown with arrows. you can see this node group in the fourth picture. Everything is normal and I can add different videos to the image textures until a specefic numbers of videos. Then when I add another video, the shader turns purple.
Is there is  posiiblty that ther would be a limit for the input?
thanks alot for taking your time
I really appreciate it

Hi :). Yes. Eevee has a hard limit on the amout of textures/shaders that can be inside one material. But this may also be caused by low memory - consider lowering the input resolution.

Ooof... I've done something similar, but I had less (about 20?) videos, and made them only about 10 seconds long... It was still brutal to wait for all videos to load on each frame, maybe it's optimized now.

Thank you guys, It was actually true

Consider merging all the videos into a single video, or at least a few videos, and then access them by positioning your UVs where the video is supposed to be.

Thank you very much for your help guys,
As you said the problem was caused because of the limit which Eevee has on calculation multiple textures.(more than it can handle). Also it wasn't because of low memory it was just because eevee is not optimized for very high amount of textures. Blender version 3.3.1


text:
How can I add multiple inputs and randomize it for other objects using it?
In this project there are multiple tv screens which I want to project different videos on different ones and It takes time to have multiple shaders for all of them. So I want to know if there is a way to choose all of the videos and randomize them for the screens, so that we have different tv screens screening different videos.

You can use Object Info Node to get a random value per object. Using this random number you can decide what image to display.
Here's one way to do it


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Lifetime Color Change Material + Time Remapping = Problem (Cycles Animation)
I am posting because I've been working on a problem all day and I can' t find the right solution anywhere. I'm going crazy. :P

My situation:

I have an animated scene in 24 fps
I want to release the final render
with animation in 120fps
The scene contains Particles, and an
important element is that they change their color over time. Example Video:
https://youtu.be/QvATUlmguyk

I've tried many different ways, but each one of them ruins the final effect in some aspects.

A partial solution to the problem I managed to come up with:

The best way I could find it was to change FPS, Time Remapping and End Frame. Below is an example of how I changed it.:

After the implementation of the above change, all animations work correctly.
However, there is a problem with Particles Material. Which, due to the change of time completely fails to work. During rendering it is completely white.
Material nodes:

I thought that to solve the problem it is enough to divide Age into 5 and multiply LifteTime x5 but unfortunately it does not solve it. Below you can find nodes that don't work.

It seems to me that the solution should be rather mathematically simple, but unfortunately I do not understand it at all. HELP! :(


text:
Local translation with pivot point established on the active object
Whenever i try to translate objects, with pivot point established on the active object, every object translates in their own local coordinates.
Video will explain it better: youtube.com/watch?v=vArDq7cqRdA
UPD: Okay, i recorded another video to make it less confusing:
youtube.com/watch?v=qFCMPoBb8Ac
firstly i show you what the trouble is, next i select 'individual origins' and there is no difference. And in the end i apply rotation and only then i get what i wanted(and what i expected)
I just wanna make sure that such a behavior is what developers wanted and this is not a bug

You should also place 2 screen captures in your question beyond the video.  It may give your question a better sense of importance.  The video at the other website  can be deleted anytime which makes the question seem less important and temporary.

You seem to be changing transformation axis from the video which should be stated in your question.  Your question description above and the video could match better.

Every piece of software has defects.  I believe what you are talking about is intended.

Here is a tutorial series if that suits you tastes. https://www.youtube.com/watch?v=lY6KPrc4uMw&list=PLda3VoSoc_TR7X7wfblBGiRz-bvhKpGkS

Moving a multiple selection with the keystrokes

gz global axis

is different than

gzz local axis

where the letter z refers to the z axis and can be replaced by any of the set {x, y, z, X, Y, Z}.  Feel free to experiment.
So having a selection of multiple objects move on their locally rotated axis is a feature.
You can [apply] a rotation.  And thus all objects would have the same rotational axis and different origins.
I do not know your long term goals for your model.  Tutorials may lead you to understand how to

[join] objects
[parent] objects
Blender always has various ways to achieve your goal.

So what is written here is not a tutorial, and you may need to search further here at BSE.  Also pay attention to the additional information which appears in Blender 3D View at the bottom, when using either of the keystrokes above.
You may appear to be changing transformation axis although the video may be clipping the lower portion of the screen capture.  You can also change the pivot center.

I believe Blender is performing as intended.  As the user you should see this behavior as a good option and not something unintended.
In the image below the Blender User first grabbed an object.  Then pressed

F6

to see the other options of the grab/translate operator.

The famous website that rhymes with noonoob has tutorials on selection transformation in Blender.  Although I have not taken the time to find one that deeply addresses this topic you may find one.
https://www.youtube.com/watch?v=JaYhhaKDh5E
https://www.youtube.com/watch?v=wklRKGC7ai8


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Custom fresnel curve
When it comes to recreating the shading of metals like chromium with such extreme reflection curves it's obviously inaccurate using one averaged reflectance curve. Also eye-balling the values appears impossible so it becomes relevant creating individual curves as accurate as possible.

Source: http://refractiveindex.info
Looks like feeding in a RGB Curves node is the way to go. However I can't figure out how accurate this mechanism is. What approximation model cycles is using? Schlick's approximation? Is there anything else to consider like shifting the incidence angle?
Q: How to build an accurate fresnel curve based on the data of refractiveindex.info?

Here is the Fresnel Conductive OSL node done in pure Cycles nodes:

The node noodles:

And .blend with linkable/apendable group if you feel lazy to build this:)

Notes:
In reality the IOR is computed like this:
IOR = N + Ki
where N is Refractive index and K is Extinction coefficient. For dielectrics, the complex part can be omitted, so N becomes the IOR. However metals do have the complex part.
You get the measured N and K values from here: https://refractiveindex.info/. The problem is, that both N and K depend on the wavelength of light.
So to render metals correctly, Cycles would have to be a spectral renderer taking into account the polarization and wavelength of light.
The best we can do is to approximate and sample just for red, green and blue light.
As per the Vray OSL reference the red, green and blue values are taken at 0.65, 0.55 and 0.45 micrometers. Put the wavelength value in there and read N and K:

The usage is same as in Scott Milner's answer. This is how the Conductive's Fresnel output can look like (with extreme values):

You can see it produces the Reflectivity color and Edge Tint color that you would normally input in an artistic-driven metal shader.  But this is from exact measured values and with correct math so the way the colors blend towards the edge is more accurate than using an artistic metal shader with hacked (usually just adjusted for the base reflectance) fresnel node (which in Cycles gives dielectric reflectance response curve).
Connect this into Glossy shader color. The shader should have 0 roughness to be correct.

[UPDATE]: As roughness increases, rays have higher probability to hit the surface dead-on as in center of the sphere. When roughness reaches 1, the whole sphere is shaded with the reflectivity color:

Here is an upgraded PBR version with roughness all incorporated into one group:

Node group guts:

Blend file:

Now this approach taking measured N and K values has GPU and roughness support - two biggest downfalls removed - which imho puts it on par with PBR artistic-driven shader setups:

artistic approach with reflectance and edge-tint color input has ease of adjustment benefit (you can also find recommended/measured color values for metals online).
measured N and K values approach gives better and more accurate reflectance behaviour (but still approximated in non spectral renderers).

+1 however, if you add an explanation about how this is better than other solutions, you would add a lot more depth to your answer.

@pycoder Hi, this is just to address the bounty request for non-OSL implementation of the OSL method (that I assume works) - so it is only better by not requiring OSL. Personally I use artistic driven PBR shaders so I just hope this will be useful for someone.

Crazy! Took me a while to understand the math behind the setup, yummy... Many thanks @Jerryno. Out of curiosity, how you would setup e.g. chromium as PBR shader? Do you really think accuracy, IOR and stuff doesn't matter down the line?

@brockmann My earlier solution uses an OSL shader, but it also shows how to properly set it up with values from, say, refractiveindex.info. The process should be exactly the same.

@brockmann The math is just copied from the OSL script, which is copied from Maya cmds code: http://forums.odforce.net/topic/23213-how-to-create-accurate-fresnel-curve-nk/ :) The usage is same like Scott wrote, you just plug the color into glossy shader. I'll add bit more notes into the answer.

How you managed to implement that script is totally awesome @Jerryno! Again, I'm grateful for your post and really appreciate your effort, thanks. Yeah, I already understood how to use that node group. The question was related to your comment, that you'd prefer an artistic driven PBR instead of using real measured values, just wanted to ask for your opinion: Do you really think using "real world" values doesn't matter?

@brockmann the artistic approach using reflectance and tint edge colors is easier to adjust to meet the desired look, there are also measured values for metals to not deviate from (ie. page8: https://www.allegorithmic.com/system/files/software/download/build/PBR_Guide_Vol.1.pdf). There are also slight differences of N and K constants based on the paper publications they were measured in. Hovewer now that I build the PBR version of metal accepting N and K all the big downfalls were eliminated putting this on par with the artistic PBR version - works on GPU and works with roughness.

Thank you for this answer and for providing the node file!
I understand the Fresnel part of the code, but not so much the roughness. For example, why is it square rooted before being fed to the glossy BSDF, and what is the theory behind calculating the cos(i) by mixing it with 1 with a factor of roughness? Is this a well-known formula, and if so, can you point me to it?
The link to the Maya cmds code only seems to discuss the Fresnel part, and I do not have the osl file on my version of blender. Speaking of, does anyone know where I can find that file?
Kind regards, Simão.

@Sirplentifus the square rooted roughness might be incorrect now, glossy and principled bsdf implementation changed and there's no need to do that now. Could be the reason why they removed the osl node, which this was just its math converted to nodes so it could run on gpu. I'll check on this later probably needs an update.

Old Answer: (revised one below)
The number you are looking for is just the Refractive Index further up on the site: Edit: Since this is a conductive material, the Reflectance value is actually the correct value for a dielectric approximation of a conductive material.

^^^ not correct!
As long as the material you are creating is dielectric, just plug this into a Fresnel node, and you should be good to go. Custom RGB Curves are not physically accurate and will not give you what you want. What it looks like:

Note: I have seen tutorials that say that Blender's Fresnel node isn't accurate, and that you have to do various things to the normal input to make it more physically accurate (Edit: as Ibalazscs said, this is only when taking into account roughness, and this method is also correct.). I tested this by creating a group of Math nodes with the Fresnel Equations and comparing it to the Fresnel node. They look exactly the same:

NodeGroup:

Revised Answer
The above answer was just for dielectric materials. The question was asking for conductive (metallic) materials. After looking through some code and reading this page from the Developer site, I found that Blender only has partial support for conductive Fresnel. It appears that it was going to become part of the Cycles node system, and then was abandoned. The developers did include it, though, as an OSL shader template, so it can still be used.
To use it, first enable Open Shading Language under the Render settings. (Note: Using OSL for this slowed down my render times a bit.)

Next, open up a Text Editor. Click on Templates > Open Shading Language > Fresnel Conductive.

In the Node Editor, add a Script node (Shift + A > Script > Script). Select the text file you just created (fresnel_conductive.osl).
Now, here's the tricky part. The IOR of a conductive material is a complex number in the form n+ik. Not only that, but it changes depending on the wavelength of the light hitting it, so the IOR is different for different colors of light. This OSL script takes only three IORs and interpolates the rest with a spline curve. It is still a good approximation, though. Onward!
Using a database like refractiveindex.info, find the complex ior for three different wavelengths of light, probably red, green, and blue, or about 0.68µm, 0.55µm, and 0.40µm, respectively. Plug the red, green, and blue values into the red, green, and blue slots of n and k on the node. My final node setup (using the Chromium values) looked like this:

Although this is an imperfect workaround, there is hope! There is an open developer page on a Metallic BSDF that would do all of this better and just built in.
Sorry that the initial answer wasn't what you were looking for. Hope that this helps more.

That's the hobbyist approach. First of all the question is about metal (non-dielectric). Also I doubt that your statement "Custom RGB Curves are not physically accurate..." is true. IOR is an overall value, as you can see in the diagram I posted, each reflection curve is different. Check out vray masterclass and you'll see adjusting the cuves individually is a common process. Thank you anyway.

Blender's Fresnel node isn't accurate in the sense that it does not take roughness into account. It is accurate for theoretical, perfectly smooth surfaces.

@brockmann "each reflection curve is different" - are you aware that the red, green, blue curves in your diagram are not for red, green, blue light, but for different polarizations, and in majority of cases only the green (unpolarized) curve is relevant? Do you want to keep track of light polarization?


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Low-Poly Mesh-Based Fur
I've been wondering how artists make low-poly 3D models look like they have hair or fur.
Recently I stumbled across this animated Corgi model on Sketchfab, and it looks like the artist made some spikes that stick out of the model to make the corgi look fuzzier and messier:

These fur spikes overlap the model and curl at random angles, but somehow the artist kept the topology pristine: The spikes and surrounding mesh are still mostly quads, and all the quads are mostly square.
How could I replicate these fur spikes and still keep a nice topology?
I tried to replicate a single spike with the "Grab" sculpting tool by pulling a vertex hard to the right:

However, the quads on this spike have become highly distorted, and the spike looks jagged and flat.

https://blender.stackexchange.com/questions/56535/how-to-make-a-spiked-sphere

Thanks for the link! I am aware of this technique for creating spikes, but it makes two assumptions that I wish not to make for the particular application of low-poly hair and fur: (1) The spikes protrude from a single vertex. (2)  Creating the spikes introduces new hexagons, and I'm hoping to stick with a minimal amount of polygons that are only triangles and quads. That was my fault for not clarifying; let me edit the question


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Maintaining Good Topology When Part of a Mesh Becomes Non-Quad
What is the general approach for maintaining good, quads-only topology when encountering an arbitrary polygon with more than four sides?
No matter how hard I try to keep a good topology, sometimes I still find pentagons or hexagons in my meshes. This happens especially when cutting/extruding organic shapes in a box-modeled mesh.
For example, this model has a clean topology with only quads:

But when I cut a triangle into the mesh, it's still mostly quads, except for a few pentagons and hexagons:

My initial reaction is to cut the hexagons in half to make two quads. But the new quads aren't square at all anymore. I have no idea what to do with the pentagons.
Here's an example of a "real" model where a decagon was created in the topology and shoulderblade of this dog:

I also encounter eccentric polygons when connecting a highly detailed part of an organic model to a less-finely detailed part. For example, this dog's face has more detail than the back of the head. I tried to convert this heptagon to quads with no success:

Many Stack Exchange questions address this question for specific examples of meshes:

Problem faced while doing re-topology - can't maintain quads
maintaining quads when cutting circles into mesh
How would you cut a shape out of an object using another object?
How to party add geoetry while keeping good topology (Cat nose)
Apply complex hole pattern to simple face while maintaining good topology
How to Remove these Ngon's with good topology?

Most of these answers work under the premise that the number of sides is even or that the large polygon has an even number of faces.

The dog topology looks just fine. What’s the problem?

Thanks! For this model, I'm primarily concerned about the face, especially the lower cheeks. When I see other models, they usually comprise a nice grid of mostly square quads, and those deform well during animation. The cheeks here seem to lack that grid pattern. Also, the little triangle at the top corner of the mouth might be problematic post-rigging.

This is more of a general question though, I care much more about learning how to make good models than rescuing/improving this one.

You dont' always need to use quads, if you have tris and ngons and it doesn't create artefacts and doesn't bother your topology flow, you dont't have to care. About the file you share, it really depends on your goal, you could leave the topology as it is and even dissolve some edges, you could make it only quads (actually you can divide a triangle with 3 quads) but I'm not sure it's really useful? It 's really case by case, and I'm not sure that it has a sense to create a topology with only quads for your shared file, unless you explain a bit more.

For your dog topology, it could be better, maybe share it if you want people to try to improve. I would make the topology turn around the mouth

@moonboots are you sure you can divide a triangle with 3 quads? Is it possible to decompose a triangle into quads without splitting edges?

you could do either (1) or (2) (see picture) but for what purpose? is it really useful? https://zupimages.net/up/21/27/t70t.jpg

in your link he says without splitting edges, I've split edges like you've done in your screenshot

for your mesh you share you could even do that: https://zupimages.net/up/21/27/dhfd.jpg ... it won't create any bad artefact in Rendered mode

Topology depends of what type of model you're creating, since every model is different...
When u want to extrude something in a certain face, but also preserve quads, u can click "i" or "Ctrl i" (can't remember the correct key), and it will make an inside extrusion that u can scale with the mouse. This can be made in a single face, or multiple faces.
Now, a "lazy" way to fix bad topology on a model that has tris and n-gons, is to use Subdivision Modifier, which smoothes your mesh, and converts the tris and n-gons into quads by making a bunch of loops... However, this might not be a good method for any kind of model, since your mesh could lose the original shape, and become more mid/high poly.
Here are a few tutorials about topology that could help (u can search for more in YouTube if u need):
https://youtu.be/rwW6HpOcAuw
https://youtu.be/xo9JRPhGi68
Hope it helps!


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Why does blender lags when I try to move objects?
I'm using blender version 3.3.1 and when I try to move objects by using the G key on the keyboard, it lags. It goes like "not responding". Also the framerate of the viewport playback is too low. I tried so many ways to solve this problem, however, I couldn't find a solution.
I used decimate modifier and as you can see in the picture I did hide the other stuff which made the viewport playback slower.
CPU: I9 12900k
GPU: Rtx 3080 Ti
RAM: 32 GB DDR5

Sometimes there are too many verts which not obvious. Try to enable the statistic to see if something is too highpoly. It is in the Overlays menu: https://docs.blender.org/manual/en/latest/editors/3dview/display/overlays.html

In the picture, the vertices are near one million. But when all of the objects are shown the vertices reach near 7 million. Is it normal for blender to lag with this system config?

Many thanks....

I have now figured it out. The decimation modifier degraded the performance of the viewport, while it worked fine without it.
In the end, there is no need for the decimation modifier to increase viewport rendering or performance.

Modifiers need to be recalculated on the fly on each frame. Decimate modifier in particular is quite a heavy calculation, and good for performance only once applied. Otherwise it's just yet another drag in performance.


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How can I fix this pointy, solidified, subdivided surface?
So, I have a fairly simple control cage for what's supposed to be a smooth surface. IOW, it's getting a subdivide modifier slapped on it. However, it also needs some sharp corners... and thickness. So it's getting a solidify modifier also.
I can get the sharp corners on the "main" (non-rim) faces... but I can't get the rim right. The trouble is that I need to solidify first (due to varying thickness that results in my model looking like garbage if I subdivide first; basically, I need the subdivision to smooth out the transitions between thicknesses), but when I do that, the rim wants to bulge in at the pointy spots, because there is no edge crease. But just turning on edge crease makes the rim (and in fact, the entire edge of the shape) pointy everywhere, which is also wrong.
It seems like what Blender should be doing is directly copying the input vertex crease to the rim edge crease, which would solve the problem.
Is there some way to do that that I'm missing? Is there some other way to fix this mess? (Again, solidify must precede subdivision.)
Here's a quick sample of the sort of problem I'm trying to solve:

This may be a duplicate of Subdivision and solidify sharp corners, but the only answer there isn't working for this case: applying a bevel modifier by angle won't work because some the corners (at least on my real model) that should be smooth are greater angle than some of the corners that should be sharp, and using 'complex' solidify (for some reason?!) removes the ability to set creases on the edges. I'd also really prefer to avoid beveling the sharp corners... while that "mostly" works, this model is ultimately going to participate in cloth simulation, and I'd really prefer to avoid the tiny faces that get generated by such method. Really, what I want is a way to just set the rim edge crease.

Can you spell out/illustrate the 'varying thickness -> garbage' part of the problem?

@RobinBetts, basically, I get linear interpolation of the heights rather than CC-smoothed. In the attached model, add every other vertex (checkerboard pattern) to a group and smooth based on that. The results with subdivision first vs. subdivision second are completely different. In particular, subdivision first gives a very jaggy/faceted "top", which isn't what I want.


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How to fix hair shape at roots?
Blender 3.3. I'm fiddling with the new hair stuff and have sculpted some fur for my model. However, I'm having trouble getting the "volume" (in the hair sense, not the CAD sense) right. Specifically, all my hairs have a sort of exponential-curve shape relative to the surface; that is, they start almost perpendicular to the surface and then point more outward at the tips.
Real hair/fur of course does the exact opposite; it's perpendicular to the skin on emergence and then lies flat(tish) against the body.
I really don't want to start over; I have direction, clumping, and tip-to-skin distances that are satisfactory. Is there any way to adjust only the roots of my hairs so that they are more perpendicular to the surface, while leaving the rest of the hair mostly unaffected?
For bonus points, is there any way to make hairs repel each other without also being repelled from the surface? (Basically, to reduce self-intersection without otherwise affecting the shape more than necessary?)
Puffing doesn't help; it's actually what produced this effect in the first place. Combing doesn't help either as it presses the hair too close to the surface. What I need seems to be a comb mode in which the hairs also repel each other and the underlying surface?

Check out Blender 3.5 if you can. It comes with a lot of improvements for hair such as pre-made Geometry Node assets to control the hair, better edit mode (still under development), new nodes for interpolating hair children, quick fur, and there is even a demo blend file with 4 different fur examples: https://www.blender.org/download/demo-files/#hair

@Blunder, thanks for the marketing spiel. Does it address this specific problem any better than 3.3? (Ability to select roots would be an improvement; can 3.5 do that?)

Unfortunately, selecting the roots is still not possible in Blender 3.5. But if you can make the selection grow as you wrote in your answer you should be able to select them when you invert the selection. -- Another approach is to use Geometry Nodes. You can rotate the hair at the roots if it's too close to the surface.

I found a method that sort-of works, although it's somewhat reliant on combing properly in the first place, plus lots of careful smoothing. It's also somewhat dependent on hairs being of equal length.
The key is enabling 'Use sculpt selection', which is an unassuming and easily overlooked icon next to the mode drop-down (i.e. 'Sculpt Mode'). Until I stumbled on that, I couldn't figure out why selection wasn't doing anything.
The "right" way to do this is to start with hairs completely normal to the surface. Newly added hairs that aren't interpolating shape will be like this. Existing hairs can be restored to this state with gratuitous use of the 'Puff' brush.
At this point, the trick is comb without affecting the roots. To achieve this, turn on 'Use sculpt selection' and choose 'Endpoints' from the 'Select' menu'. You should notice the hairs dimming. Now choose 'Grow' from the select menu a few times, watching as the tips of the hairs lighten to indicate that they are selected; stop before the entire hair is selected. Now, combing will only affect the selected part of the hairs.
This will of course result in some nasty kinks where the selected and unselected parts of the hairs meet. Gentle grooming starting with more hair selected and gradually reducing the selection might help, but judicious use of the 'Smooth' brush should also be able to set things right.
A similar trick can be used to try to repair hairs that have been overly flattened, although once the bulk of the hair is too close to the surface, it's quite hard to repair without starting over. That said, if a sort of 's' curve is acceptable, selecting most of the hairs as above, then choosing 'Invert' from the 'Select' menu, will allow using the 'Puff' brush on just the roots. Again, this can be done incrementally and/or cleaned up with 'Smooth'.
(It's most unfortunate that there is no ability to directly select roots.)


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How to line up a point to two views?
I managed somehow to use Blender's built-in photogrammetry to get the camera on two frames to be aligned to two "different" (actually, the same image but mirrored) reference images.
I am, of course, trying to recreate a 3D object from 2D images. With the view set to the camera and the reference image as background, I can easily trace over one of the reference images, but the points are only correct in that their 2D projections in that view are correct; when I switch to the other view, they are of course nowhere near where they should be.
By switching to the other view, moving the point to the correct location, switching back, and repeating many times, I can eventually get the 3D position of the point to be approximately correct. However, this is incredibly tedious.
Is there a faster way to go about this?
Ideally I would like to be able to do two things:

Be able to position a point in one view, then in the other view move it along the camera ray associated with the point's projected position in the first view.
Draw something (an annotation would be most convenient) in both views which represents the surface of a 2D curve projected in the respective views and obtain the intersection thereof.

Step 1:
Draw a "mesh" on top of one of the images (do all of these in ortographic views)

Step 2:
"Duplicate" that mesh in "object mode" and place over the second image.
As you know, the mesh will not match the image.

Step 3
"Move" the vertices of the new mesh to their right positions.
Important:

You shall NOT delete or add any vertice! (there must be a correlation between the two meshes and that correlation will be the index of each vertice)
Try to move vertices only horizontally or in the direction of the camera displacement (we want the points on each mesh to be stereoscopic pairs)

Step 4
LETS HAVE FUN!!!
Get these geometry nodes ready.
(PS: they work when you draw on the XY plane, while the camera displacement is on X)
Main setup:

This setup:

Centralizes the two meshes based on their bounding box
For each point, gets an intersection between lines coming from two virtual camera positions
Sets the position of each point at that intersection

Center images group

This just superposes both meshes at their centers, where "Vector mean" is a group making (Vector1 + Vector2) /  2
Intersect lines 2d
This is pure math intersecting two 2d lines

Result
A beautiful 3d mesh arising from the geonodes!
(You need to adjust the "camera distance" and the "camera offset" input values to get a sensible result)

File:


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Turning hairs into texture-spots?
Just came across How to I make a plane wrap around and object? which asks about adding spots to a character model. One solution suggested a Voroni texture, which is probably the "correct" easy way to go.
However, it got me thinking about a different solution that seems like it should be feasible. If I wanted to add spots to a model (Sue's head will serve as an examplar), but I want to be able to control the size and position by placing hairs at the center of the spots and making them longer/shorter to adjust the size, is there a way to achieve that?
Essentially, for each fragment, I want to select the nearest hair, then apply a ramp scaled by some constant times the length of that hair. (Producing a Voroni from the set of hair points is a good start, but the shader also needs to know the length of the hair associated with the fragment's cell.)
For bonus points, the shader would compute the minimum of the scaled distance to all hairs, but we can assume that isn't necessary.


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Image alignment with 3D space
I have a 3D scan of a site and need to align a photograph that is taken on a different time of year. I have tried using fSpy, but as the axis are not very clear it is not working. Does anyone know of a way that I can define some key points and have the camera align?

Interesting question, but I'm afraid fspy won't help you here. The buildings are too far away and the orientation of them differs too much. You will have to adjust this by hand.

If you have more overlapping photographs from different positions, you could use Blender's camera tracking functionality intended for video tracking to find camera positions and then match some scene features to your 3d model. It pays off to take a few(5-10) photos of the scene even if you only need a single still image precisely for this purpose.
Else than that, fSpy is pretty much it for this as far as I know. If it doesn't work, the main thing is to find the right camera settings like sensor size and focal length of the lens. Only then you have a chance of matching it by hand. There might be some useful info in the metadata of the photo file like camera make and focal length of the lens if it wasn't you who took the photo and don't know this info already. It makes things way harder if the photo is cropped, so you should use a version of it that wasn't cropped as well.


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Why is this happening?

This weird connection lines appears when I use texture paint.
How can I get rid of this?

Hello and welcome! can you share a blend file https://blend-exchange.com

Your UVs are outside the UV region look at the sides of them, the texture for the UVs that are outside the UV region gets repeated so you gotta re-unwrap and scale it to smaller than the bounds of UV region


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Transparent Objects get blown out when rendered but is fine in viewport
I’m working on a scene right now with a vine and leaves. The leaves are made with a plane and an alpha image of a leaf. It was initially made using the leaves as a particle system but when I would render the leaves get huge and the scale got messed up and the transparent parts show up black too. I have blending mode set to Alpha Clip and displacement to bump only.
Once that didn’t work I tried applying the particle system and all the transforms and that hasn’t worked either same issue. It looks fine in the viewport display rendered view so it must be something missing in the render settings. I'm using Cycles. I attached the render, the viewport display, and the shading settings as an image, Any help is greatly appreciated!

Did you check for hidden objects? Alt+h

Check the modifiers on the plane object. It's possible that there are different subdiv levels or a solidify that's toggled off for render. Not sure why alpha could be missing, but Viewport Display settings (blending mode etc) don't matter for Cycles at all.

That worked @Vagabonk , looks like the leaves were hidden from a previous version. Thank you so much! Its an obvious solution that I overlooked, still not sure why it gave me that result, but at least it worked out. :)


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move a vertex to the position of another vertex (different object) in python?
i basically need this:
How do I snap one vertex to the position of another vertex in a different object?
to be done by a python script.
i've managed to move a single vertex along one axis so far..
my problem is, that i struggle with the orientation options in blender.
i would like to select vertices from object2 via index (no problems so far) and copy their location and save these values to the selected vertices of object1.
why is it, that for example bpy.data.meshes['Cube'].vertices[0].co doesn't give you coordinates from 0,0,0? sorry for my noobishness..

You have to copy the values, I guess you are getting pointers instead try with. .copy()

Also if you post the code you have so far it would be easier

I wrote this example script for you. Mind the comments.
import bpy
import bmesh

# Get the coordinates of the first vertices of 'Plane' object
firstObjData = bpy.context.scene.objects['Plane'].data
bm1 = bmesh.new()
bm1.from_mesh(firstObjData)

bm1.verts.ensure_lookup_table()

# Convert local coorinates to world coordinates before assignment
vertCoordinates = bpy.data.objects['Plane'].matrix_world * bm1.verts[0].co.xyz

print(vertCoordinates)

# Set the coordinates of the first vertices of 'Cube' object
secondObjData = bpy.context.scene.objects['Cube'].data
bm2 = bmesh.new()
bm2.from_mesh(secondObjData)

bm2.verts.ensure_lookup_table()

# Convert world coorinates to local coordinates before assignment
bm2.verts[0].co.xyz = bpy.data.objects['Cube'].matrix_world.inverted() * vertCoordinates

bm2.to_mesh(secondObjData)

thank you for your time! your code saved my life (at least many hours).


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How to animate a radial engine?
I have already asked a question based on this topic today which was well answered. It is related to my new question so I put the link
here!
First I will post a picture for clarity.

My aim is that the red "ball" is moving on the path with the red flashes (it's a bezier circle), additionally it should not rotate on its own axes.
The Blue, Green, Yellow, and other "balls" should follow the Red one and also move the pistons with the same color towards and away of the center of the whole construction.
I tried the solution which was suggested in the last question I asked and it worked well, but with these new "conrod endings/crankshafts" it doesn't  work anymore. I have also tried to make the red ball follow the red line via "Follow Path" constraint but then the method of "Copy Location" for the pistons it doesn't work anymore.
I'm very sorry for such a specific question. Maybe I should just build a V engine ... but then again I guess I would have the same problem with the crankshaft.


text:
Make a 3D tube with a Bézier curve, bevel not working
I'm following the answer of this question: Make a 3D tube with a Bézier curve?
Now i set the bevel of the curve larger and the curve becomes higher. But there is no tube. It's just flat.
The same thing happens when I used this tutorial: http://wiki.blender.org/index.php/Doc:2.4/Tutorials/Modeling/Curves/Making_A_Tube
Here is an image of the problem i face:

It's not a tube.
Edit:
Blender file: http://www.pasteall.org/blend/40010

please upload a test blend file

@Chebhou Updated

the Bevel is working fine just the scale of the curve on X and Y axis is too small (0.05) compared to Z axis scale (1.0)  just fix the scale ( set them all to 1.0 or 0.05) and the bevel effect will be clear


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How to render just one scene?
I have a blender project with 4 separate scenes which get combined in the compositor.  Every time I hit F12 or press the render active scene button, all 4 scenes are rendered. Is there a way that I can just render one scene?

Not sure if you mean this, but I think you clicked the 'Render' button in the properties panel (which is the same as pressing F12). But if you click the small 'render' button in the compositor (Node Editor) it will only render that scene.

Does the scene you are currently rendering have compositor nodes?  If so: rendering that scene requires it to render all the compositor inputs.  You can deactivate the compositing step by unchecking the Compositing checkbox in the Scene > Post Processing properties.
You might also consider creating an entirely separate scene for the compositing, then render the other 4 scenes to stills.  Use the stills as input to the compositor instead of scenes.  This might speed up the workflow as you are tuning the compositing.

Yes, the other three scenes are combined in the main scene's compositor, so I can't just disable the compositor.  I thought about creating a separate scene, but that just adds a new layer of complexity.


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Soft body collisions give missing cache error
Sounds like I'm having the same issue as this question (Missing cache error) but since that has no answers, I figured I'd post this question with a working example of my issue.
I have a bunch of tubular structures that I build and mesh using metaballs. The issue is that sometimes there is a small amount of overlap between the meshes so I've written a script which uses soft body collisions to reduce the overlap (this may be overkill but I've found no other satisfactory way to do it).
The problem is that when I have more than a couple of meshes, I get this 'missing cache error' being printed to the console over and over again. It doesn't actually stop the simulation but that much printing to the console slows the whole process down.
You can download the .blend file with ten meshes and the soft-body script in it to see the problem for yourself here .
Does anyone know the cause of this error message, whether it actually affects the result of the simulation and how to stop it?

Welcome, @bigbadpiano. Use this link to upload the file: https://blend-exchange.giantcowfilms.com/

My bad, I've updated the link

Not exactly a general solution to the missing cache error but I solved my problem.
I think the error has something to do with the physics simulations running with all the separate meshes that have no physics modifiers attached to them alongside the meshes I'm interested in that do have the physics on.
I solved this issue by using collision groups so that each mesh only interacts with those that it overlaps with anyway.


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Use self and the slow python expression
In putting together an answer to Changing Multiple Influences Simultaneously I came across the Slow python script warning in the drivers editor
Using a set up as outlined here driving a pose bone's constraint influence with the armature objects "prop" property
Using a traditional driver variable

And again using the use_self property of drivers. Since the drivers are on on pose bones, and the id data of a pose bone is the armature object then self.id_data is that object and self.id_data["prop"] (or self.id_data.get("prop", 0)) is the value of the custom property "prop" on that object.

However this displays the Slow Python Expression warning
What are the implications of this warning? How is it flagged?
Could be related: (possibly another question) how much of self is self... In trying to game the system with drivers tried to manipulate the self.children via a parent object driver, only to find the collection empty in the driver namespace. The method also flagged the warning

It's important to note that just like there's simple/slow differentiation, for slow (Python) there's also safe/unsafe. For a whitelist of allowed Python names and opcodes, see driver not working - using something outside of that list - like self - will require enabling script auto-execution.

Expressions containing:

variable names: only ASCII characters.
literals: floating point and decimal integer.
globals: frame
constants: pi, True, False
operators: +, -, *, /, ==, !=, <, <=, >, >=, and, or, not,
conditional operator A if B else C
standard functions: min(), max(), radians(), degrees(), abs(), fabs(), floor(), ceil(), trunc(), round(), int(), sin(), cos(), tan(), asin(), acos(), atan(), atan2(), exp(), log(), sqrt(), pow(), fmod()
blender provided functions: lerp(), clamp(), smoothstep()

fall into Simple expression category and:

are evaluated directly, which improves performance on multi-core systems
are evaluated even when Python script execution is disabled
don't get the "Slow Python expression" flag

Would you consider it in many cases ignorable?, eg self.location.x gets the warning, making same as a variable (similar to above)  doesn't. Not using self  requires editing for each object copy to change variable target.  Appears then any use of  self in drivers requires the auto-run python scripts ..and hence slow warning if python is enabled. Cheers.

@batFINGER it depends, using the variable makes Blender treat it better and results in better multi-threaded performance, even though both are the same thing. If there are couple drivers like this it doesn't matter, but when there are hundreds, it may have some noticeable impact, I never encountered it though.


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"Boolean" operation on bézier circles
I would like to make a cross section like this (only the hatched part)

(image source)
using bézier curves/circles, to then use in a screw modifier and make a drill bit.
I initially thought I could use a Boolean operation (difference) with a set of Bézier circles like this:

but for Béziers there seem to be no Boolean modifiers. When I convert them to mesh (using Alt-C), the Boolean modifier becomes available but "difference" has no effect.
Apart from manually shaping a curve (by dragging nodes and handles), is there another, more "mathematical" way, of achieving the result?

Use Boolean modifier after adding some thickness to circles so modifier to work or use Knife Project.
Cutting with Boolean modifier
Boolean didn't work in your case most likely because there wasn't geometry needed for it to operate with. Two flat faces won't be cut with any Boolean operation; if you extrude these faces in any direction (e.g. by Z axis) and then add the Boolean, it will be executed correctly.

First fill the circles with geometry: if they are still curves convert them to 2D; if they are meshes select all the vertices and press F. Position them accordingly: center one should be as separate object, and 3 others should be joined as another one.
Extrude them / add Solidify modifier; you may leave small values in order the extrusion to be deleted further on as double vertices (increase threshold a bit to achieve that).
Finally add Boolean to the center circle and choose object with 3 circles as a target. Delete created additional geometry if needed.

Knife Project
It's basically described here. In this case you shouldn't extrude anything. Some general steps:

Place circles as in the 1-st way;
Select those 3 joined as the first object, then one in the center and enter their Edit mode (the selection order is important because it determines where faces will be cut from).
Press  Numpad 7 to enter Top View. It will make Knife Project to cut object using this projection.
In the Toolshelf (open with T) find Knife Project and choose it.

See also:
Cases where boolean operations can fail
How would you cut a shape out of an object using another object?

Great, thank you!
A few comments after experimenting:

On Cutting with Boolean modifier

step 1: converting bézier circles to 2D is not enough it seems (I can't extrude/solidify them in the next step), they need to be converted to mesh (Alt-C -> Mesh from Curve).
by using a Solidify modifier in step 2, it's easy to convert the result of step 3 to a bézier curve again. Just apply the Boolean modifier, remove the Solidify modifier, and do Alt-C -> Curve from Mesh. (Optionally use the "Simplify Curves" add-on to finish.)

On Knife project:
I found it works best with

the middle circle (the object to be cut) being a bézier circle converted to mesh (with Alt-C) and filled (Edit mode, select all, F), but not extruded/solidified
and the other three circles simply three bézier circles joined into one object (as bézier circles), without filling/extruding/....

@Abel 1. of course you should convert curves to mesh first if extrude needed as it's done on faces in this case which are present in case of mesh. Sorry for not mentioning that 2. I mentioned that no extrusion is needed if Knife Project is used (it still should work though). I didn't notice any changes in its work regardless of whether 3 other circles are curves / meshes and filled / unfilled. So these are tiny details which imo make difference only in workflow (but may be important in terms of convenience).


text:
Why is part of mesh deformed by IK Constraints
I have been learning to model characters in Blender for the last week or so and am stuck with my 4th attempt and really don't want to start again when I am close to getting it to do everything it should this time.
My problem is that the waist (torso) area of the character has become deformed since adding IK Constraints for the lower legs. I have had to set the chain length to 2 for these constraints so that when I drag the torso bone up and down again the whole body jumps and lands on the ground naturally (arms and legs behave as expected when jumping) as if the character has jumped by itself.
If I set chain length to any other value other than 2 the waist deformation problem goes away but then the feet don't bounce back when landing on the floor. They goes through the floor instead.
I have tried changing different settings regarding the constraints but no matter what I change I can't keep the effect when landing as it is currently is at 2 and also fix the waist problem.
Any ideas what I can try please?

Link to .blend:

Switching the pole angle to -90 alone will result in the leg bending backwards and breaking knee caps when you play back the animation. To fix that, I added a Limit Rotation Constraint above the IK Constraint for each leg. I found Rotation Limit values (differing for each leg) that allows the frames of animation to look correct without the mesh distorting or bones bending in the wrong direction:

Uploaded the edited .blend here:
This seems like a quick fix, and I would love to hear more experienced rigger tell some preventative measures that you could take to avoid IK twisting issues in Blender.

For the deformed hip this is the solution ...

Select your calf bone / lower leg bone
Bone Constraints Properties panel
Change Pole Angle to -90 degree.

Other Observations
Additionally, I have observed that your rig would greatly benefit from collar bones which were missing.


text:
Exporting Animation to FBX Issues
Just looking for some advicee - I'm looking to export this scene as an FBX with each fish (50 of) following it's own animation. Every time I export it, the fish compact into one animation within the fbx instead of their own independent 50 individual animations. The models seem to incorporate just one of the 50 animations instead of their own respective ones. Any help is appreciated!
https://drive.google.com/file/d/1dMZSjkbK9pYgbZ4EgzsY2lpVQiDddfEW/view?usp=sharing

Please find a zip folder with the blender file and textures attached :)

fbx animations are problematic. don't use fbx. similar issue here https://blender.stackexchange.com/questions/272119/animations-play-differently-when-exported?noredirect=1#comment466497_272119

@HarryMcKenzie is there a format you would recommend? I'm trying to import the asset into unity / omniverse

on another note try to read the comments in this report https://developer.blender.org/T65768 maybe this can help with multiple object animations


text:
Create a button for additional thing and for having a sequence in Panel
I want to add a sequence to my addon, for that I created 2 buttons Next and Back but I could not figure out how those buttons work.
I looking for is that when I click on the Next button then the second code should pop up. The second code can be seen in the second screenshot and I want that exact same as it is. After that when I add any object by those operators, those operators should be removed from the panel only properties and the Subdivide button should be left.
import bpy

class ADDON_PANEL(bpy.types.Panel):
    bl_label = "Add Objects"
    bl_idname = "pl.add_mesh"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Add Objects"

    def draw(self,context):
        layout = self.layout

        #The buttons in the beginning
        col = layout.column(align=True)
        col.label(text='Welcome to our addon.')
        col.label(text='Press Next to continue')
        row = layout.row(align=True)
        row.operator('op.back_thing', text='Back')
        row.operator('op.next_thing')

        #The buttons in the mid
#        layout.label(text='Select object you want to add')
#        col = layout.column(align=True)
#        col.operator('op.add_cube')
#        col.operator('op.add_uv_sphere')
#        col.operator('op.add_monkey')

        #The buttons in the mid-process
#        if bpy.context.active_object:
#            layout.prop(bpy.context.object, 'location')
#            layout.prop(bpy.context.object, 'rotation_euler', text='Rotation')
#            layout.prop(bpy.context.object, 'scale')
#
#        row = layout.row(align=True)
#        row.operator('op.back_thing')
#        row.operator('op.next_thing')

class NEXT_OP(bpy.types.Operator):
    bl_label = "Next"
    bl_idname = "op.next_thing"

    def execute(self, context):
        return {'FINISHED'}

class BACK_OP(bpy.types.Operator):
    bl_label = "Back"
    bl_idname = "op.back_thing"

    def execute(self, context):
        return {'FINISHED'}

class ADD_CUBE_OPERATOR(bpy.types.Operator):
    bl_label = "Add Cube"
    bl_idname = "op.add_cube"

    def execute(self, context):
        bpy.ops.mesh.primitive_cube_add()
        return {'FINISHED'}

class ADD_UV_SPHERE_OPERATOR(bpy.types.Operator):
    bl_label = "Add UV Sphere"
    bl_idname = "op.add_uv_sphere"

    def execute(self, context):
        bpy.ops.mesh.primitive_uv_sphere_add()
        return {'FINISHED'}

class ADD_MONKEY_OPERATOR(bpy.types.Operator):
    bl_label = "Add Suzanne"
    bl_idname = "op.add_monkey"

    def execute(self, context):
        bpy.ops.mesh.primitive_monkey_add()
        return {'FINISHED'}

classes = (ADDON_PANEL, NEXT_OP, BACK_OP, ADD_CUBE_OPERATOR,ADD_UV_SPHERE_OPERATOR,ADD_MONKEY_OPERATOR)

def register():
    for cls in classes:
        bpy.utils.register_class(cls)

def unregister():
    for cls in classes:
        bpy.utils.unregister_class(cls)

if __name__ == "__main__":
    register()

You would add that into the poll method of your menu. Basically a method that checks for certain conditions of your current context to see if it should be shown or not. See the Rigify addon for an example of this kind of thing

I want them in the same context as they are now, I want the next button to work properly as it should.

This doesn't really make sense with the UI template your using and doesn't really make sense with how Blender works. Just do a props_dialog or a popup and put all of the properties in one dialog. If it gets too for that then maybe movie into the properties panel and do it there. Blender is all about minimizing clicks. No one in the middle of a workflow wants to have to sit and click "Next" 4x for no reason.

Also that's not how col.operator() works. Clicking that button will just call the operator immediately. You might need to create custom scene properties and then refer to those in a bigger operator.

This one seems okay, I will give it a try.
Thanks


text:
Change render resolution
I am currently making some isometric sprites and I'm trying to get them to fit in a grid, but blender won't allow me to set the resolution to where I need it.

I'm trying to get the least amount of empty space around the mesh.
I'm also using an orthographic camera.
also if this is too confusing:
How get horizontal edges of camera to horizontal edges of mesh without vertical edges of camere go out and be all fucky

Perhaps the render border is the feature you're looking for?

Thanks, this'll do fine.

Changing resolution does not change the view size of the camera when in orthographic mode. You have to either change the size of the object you are looking at or change the ratio of your resolution.
Ex: 10,000 x 10,000 will be the same as 25 x 25 while in orthographic.


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How to copy indices from one mesh to another ? (vertex numbers/index/id) (the same uv)
I have two objects with the same number of vertices. I dont know how, but one object got its vertex numbers  changed (indices) As you see on the picture numbers on one are diferent than on the other. Is there a way to transfer these numbers to another mesh so they both could be the same? I have the same working UV ready for both meshes, will it help somehow to establish the numbers ?

Not sure if this helps you but you can sort the vertices with Mesh > Sort Elements .... If you sort the vertices of both objects in the same way the order should be the same.

Thank you for tip!  I just tried those options that You mentiond, somehow non of those made numbers in boath meshes the same...  it sounds like it should at least make both meshes sheare the same numbers in the same places, somehow it doesnt. Or is it me doing something wrong?( i selected sorting elements while both meshes were selected)

Oh yes, I see. The problem is the sort order criteria (cursor distance, axis, etc) and the fact that the meshes are similar but not the same. This varies the distance to the cursor, for example, and results in a different order. Unfortunately, shape keys rely on the indices. You can't make the meshes have the same shape this way.


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How to move UV island together with texture - that is assigned to that island?
Very often when i finiSh working on UVs and textures for object, im being asked to edit uvs and textures. So what would save me a lot of time, would be if there was an option to move the island together with texture assigned to it. Is there an option to do this ? How you guys deal with fixes like this?

hello, strange, how could you move the image part along with the UVs?

I'm not sure how this could work. UV texturing usually uses a fixed image texture and the UV islands placed upon according to what they are supposed to show. If you move the UV islands like in your screenshot and the part of the image below follows, then you could overlap image parts used by other UV islands. To avoid that, other islands and image parts should be moved as well, which would end up in moving all islands and the complete image together, i.e. no change at all. If you have to move image parts, the best is using an image editor. Or I simply don't understand what you need.

On my second sentence: of course it's not necessarily a fixed image texture, you can as well have a UV layout, export it and create the texture according to where the islands are. But often you have textures with special images you want to place on the mesh, so the UVs have to be moved to those parts of the image, not vice versa. Even if you paint a texture matching the UV layout, it's usually a fixed image aferwards.

This is definitely possible, but tricky. 1. A custom operator that moves UV points, and while moving them, runs a function modifying the image using Python. 2. The function would be tricky to write without opencv library, which is not bundled with Python, so you would have to install it. https://stackoverflow.com/q/30901019/1149282

I made as Software to solve problems like this: https://www.uv-remap.com/ There is a simple tutorial on the website.

I found an easy way to bake a new texture :D that solves my problem!
THAT WORKS!
Which is a perfect solution for me. This is link to tutorial on how to bake a new texture after you changed up the UV's. Tutorial: Possible to bake texture to new UV map?
This is solution by gandalf3♦ oryginaly a reply for diferent but similar question.
Thanks!

.

Simple method
Let's say You have Susanne:

If you want to move her eyes, you can load the texture in a 2D program, e.g. Photoshop, select and then move the the eyes like so:

Write down the offsets:
X: 795.05 - 903 = -107.95
Y: 395.45 - 301 = 94.45
Divide these offsets by width/height to normalize them, and flip the Y coordinate (because in Blender Y rises up, but in Photoshop it rises down):
X: -107.95 / 1024 = -0.105419921875
Y: 94.45 / -1024 = -0.092236328125
Load the new texture and move the islands by those numbers:

Thank you Markus von Broady for your hack to change position of islands :). I really appreciate your explanation with pictures. However, it still seems very time-consuming. I will be trying method with baking from this link: https://blender.stackexchange.com/questions/15510/possible-to-bake-texture-to-new-uv-map  If it would work it would be the quickest method. If it works I will post it here.


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Why do black pixels appear when rendering image with alpha?
I have a png image with alpha with transparen areas. I am rendering it with transparent backgraund adding red background in compositing, but black pixels appear on edges of shape on image. How can I remove those black pixels? .
File with image used:

Hello could you please pack your image and share your file?

yes its here https://fileup.to/5ioj/ground.zip

thanks but you first need to pack your image (File > External Data > Pack Resources)

And please upload the file with the packed image here: https://blend-exchange.com and follow the instructions there instead of some external source where we have to wait before we can start the download.

thanks i packed it here:

The Denoise function in Blender is quite good, but it cannot do magic. You have set the Max Samples for Render to 1. This is very low. Increasing it to 2 is still very low, but gets rid of the artifacts.

Apart from that the low samples make your texture very blurry. Compare the left image at 2 samples with the one on the right at 50 samples (especially the area pointed at). And the render with 50 samples took only 0.2 seconds longer.

Thank you so much! It looks so much better now, very helpful information!

@Hanya And beware that although in my example 2 samples were enough to get rid of the artifacts, this is because I rendered at a size of 50% as your render settings were in the file. At 100% the texture will have a higher resolution and then there is more potential for noise/artifacts, 2 samples are not sufficient anymore. So you have to find a balance between low samples to reduce render times but enough samples to get rid of artifacts.

I always struggle when doing renders, and now knowing all you said will make me more comfortable when doing renders. I will try ro find the balance, thank you!

@Hanya Some people even consider 500 samples still low, for my renders 200 samples are sufficient most of the time. But there's other things as well in your file, for example the Light Paths > Max Bounces settings in the Render Properties. They are all set to 1 except for Volume and Transparent. As soon as you are going to render things like glass, the Glossy and Transmission bounces are far too low to give good results (and then you have to increase Total as well), and if you put more objects with alpha transparency in a scene, the Transparency at 10 is very low, too.

Its because I was rendering animation, so I realy wanted to have as short render time as possible. (i used some youtube video to help me shorten the time)

I cannot give you a general answer. If you want to render animations quickly, you need low values. But as soon as you have glass, alpha transparency etc. it can start to look bad. But even higher values don't have to slow down render times very much - it also depends on how much complex geometry using these bounces is present in the scene. In my answer here you can see a comparison how the glossy bounces influence the look of glass for example: Grey artifacts in glass bottle

For example, my settings are like this (but I don't render animations very often): Total 64, Diffuse 4, Glossy 32, Transmission 64, Volume 1, Transparent 128. And in my answer here are other examples of how the bounces influence the look: Why does my glass shader have this black artifact?


text:
render on a transparent background (volume is almost invisible)
I ran into a problem. If I render on a transparent background, then the output volume is almost invisible.

As you can see, the fire after the render almost disappears. :(
That is, I try to get the result like on the left preview
In addition:
If I remove the transparency, everything becomes normal, but the point is to get a tank with a shot on a transparent background

Thank you in advance! If something is wrong, feel free to edit

The problem was solved through the composer.
I found the answer in one of the old posts of one of the participants Gez.
In discussion: Transparent Image different in viewport than render
Another pretty good solution, namely the “Attempt 1”. Thanks to the user jozxyqk
https://blender.stackexchange.com/a/32964/63657


text:
How can I reassign or move vertexes of a vertex group
How can I update/modify the xyz coordinates of a vertex group.
I can get the vertex coordinates of the vertex group. BUT, what I want to do is reassign or move the vertex coordinates to a new list of coordinates.
I'm completely lost. It seems that I have the right context and data, but then I cannot figure out how to update/change the coords of the vertices. I've tried a number of things.
So here is the code raw. I first get the coords of the target vertices which are selected in the viewport (object), then I 'get' and print the vertices of the vertex group that I want to update coordinates to (see code).
BUT I can't figure out how to update the vertex coordinates. It's probably a noob easy-do but I can't figure it out!! Any help thanks!!! I'm going crazy here trying to figure this out.
import bpy
import bmesh

obj = bpy.context.active_object
objdata = bpy.context.active_object.data

vertices = obj.data.vertices
vertstarg = [obj.matrix_world * vert.co for vert in vertices]

# coordinates as tuples if needed
vertstargtup = [vert.to_tuple() for vert in vertstarg]
#print(vertstarg)

#bpy.ops.object.select_all(action='DESELECT')
for obj in bpy.data.objects:
    obj.select = False

#holy cow. have to make the object active before selecting. makes sense now.
bpy.context.scene.objects.active = bpy.data.objects['crvface.001']
bpy.data.objects['crvface.001'].select = True

obcage = bpy.context.object

bpy.ops.object.mode_set(mode='EDIT')
bpy.ops.mesh.select_all(action = 'DESELECT')
bpy.ops.object.vertex_group_set_active(group='cagefacepts')
bpy.ops.object.vertex_group_select()

vgVerts = [ v for v in obcage.data.vertices if v.select ]

print(vgVerts)

#Ok so clearly I can access the vertices of obcage.data vertex group,
#but how to I update the coords from objcage.data.vertices to the list from
#vertstarg, which is a list of vector coords [or tuples if needed]???

Thanks for all advice; I checked out the vids and stuff/info in the replies, but these are very simple things that I'm reasonably familiar with. What I can't do is set or modify the vertexes of the vertex group. I'm sure there must be some way to access the '.co' but cant figure it out still...

Your script is going into edit mode, so you need to use bmesh to update the edit mesh data.
bm = bmesh.from_edit_mesh(obj.data)
for v in bm.verts:
    v.co = (v.co.x + 0.2, v.co.y + 0.2, v.co.z + 0.2)
bmesh.update_edit_mesh(obj.data)

You can directly access each component of each vertices location.
v.co.x += 0.2
v.co.y += 0.2
v.co.z += 0.2

You can leave the object in object mode and still work with bmesh data -
bm = bmesh.new()
bm.from_mesh(obj.data)

for v in bm.verts:
    v.co.x += 0.2

bm.to_mesh(obj.data)

As you only want to move the vertex locations, you don't need any bmesh features, so you could leave the object in object mode and edit the mesh data directly, this is the vertex data you get in vgVerts. If you change this data directly while in edit mode, the edit mesh will overwrite any changes.
for v in obj.data.vertices:
    if v.select:
        v.co = (v.co.x + 0.2, v.co.y + 0.2, v.co.z + 0.2)

Thanks very much for this. I think I understand now. Much appreciated.

tuples are read only you cant reasign its value.
try to use to_list() instead... i think.
[list(vert) for vert in  vertstarg]
then seems like you are doing nothing to your verts but selecting
grab the header bar down (the file menu) to see some info from operators. or go to de scripting window, there is on the top also.
almost every thing you do inside blender is shown on that "console"
see https://www.youtube.com/watch?v=2j75AM1Mttc

Yes that is just selecting. What I need to do is reassign the new coords to the the selected vertex group list. Tuples are not necessary just included as an option. I can remove tuples and does not change the workflow.
Thanks for your help.

if u do print(dir(vgVerts)) it shws all the methods avalables for that object, you just probably can do:  for vert in vgVerts: "\n"
something like vert.location or vert.position = [0,0,0] # this is the x y z values.

https://www.youtube.com/watch?v=3Q9lTBZFfp0

Did the print(dir...), here's what I get. Can't find or set the vertex data from this.

print(dir(vgVerts))
['add', 'class', 'contains', 'delattr', 'delitem', 'dir', 'doc', 'eq', 'format', 'ge', 'getattribute', 'getitem', 'gt', 'hash', 'iadd', 'imul', 'init', 'iter', 'le', 'len', 'lt', 'mul', 'ne', 'new', 'reduce', 'reduce_ex', 'repr', 'reversed', 'rmul', 'setattr', 'setitem', 'sizeof', 'str', 'subclasshook', 'append', 'clear', ...]