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How to select leaves on a sapling-addon tree when selecting their branch?
I'd like to use Ctrl+Numpad + in edit mode to select branches and leaves on a tree generated using the sapling add-on. I have a workflow to connect all of the branches to the trunk. However, I'm not able to find a way to connect the leaves to the mesh so they can be selected along with the branches.
Is there a way to generate the model or modify the models so that leaves can be selected as vertices along a branch are selected using Ctrl+Numpad +?

Example:

Add a sapling tree to a model. Enable 'bevel' and enable 'show leaves'.

Convert the tree curve into a mesh in object mode.
Go into edit mode. The mesh for branches and the trunk are part of the same object and intersect, but are not connected.

In edit mode, select all vertices, the Ctrl+F and select 'intersect (knife)' and on the toolbar select 'Self Intersect' and deselect 'Separate'. This will create merge the meshes and they will be connected at the intersections. Since it is connected, it is now possible to select trunk and branches using Ctrl+Numpad +. (See [stack exchange question] discussing the process3)

If connected vertices are continued to be selected, the leaves are not selected. Is there a way to modify the leaves so as the branch is selected, the leaves are also selected?

Sample blender file:

I see no obvious way to do that unless said leaves are physically connected to the corresponding branch. You could go and create vertex groups for each branch and assign them to the leaves as well but that requires lots of manual labor.

This could probably be scripted, but I'm not aware of a non-programmatic way to solve this.

The leaves can be connected to the sapling mesh through the following steps.
1) In object mode, select the tree and the leaves.

2) Press ctrl+J to join the meshes.

3) Enter edit mode and select all using A.

4) Press ctrl+F and select 'Intersect (knife)' and make sure the Separate option is unselected and the Source is 'Self intersect'.

5) Now the mesh is fully connected, including leaves. Selecting a vertex and using ctrl+numpad + will select all of the connected elements.


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Load different mesh on each frame of an animation
I have several hundred meshes which describe a constantly changing surface like waves in the ocean. The amount of data in the meshes is so large, it will not fit in a single blender file.
I could manually load the mesh, render, and repeat, but that is not practical,
How can an animation be setup to replace a mesh on each frame? Ideally, the mesh in an object is replaced at each frame so materials and other settings are kept.
Are there any alternatives to scripting?

In a "single blender model": Do you mean a single Blender file or a single Blender mesh object?

@Leander, thanks for the comment. The question was updated to clarify.

Alembic cache behaves like series of meshes, Blender also supports series of such cache-files. Maybe it will help

You can make a script that loads you the mesh and assigns it to your object and append the script to frame change app handlers. You also probably want to remove the old meshes data there. Then you can just render the animation as usual. https://docs.blender.org/api/2.79/bpy.app.handlers.html

I would definitely look into exporting as Alembic files.

I'm investigating this add-on - https://github.com/neverhood311/Stop-motion-OBJ

source: Stack Exchange

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

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

sort: votes


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Boolean Hole Difference causes messy subdivsion
I am trying to make a boolean cylinder cut into a mesh, but no matter what I try, the results are messy when I try to add a subdivision modifier.
Here is a screenshot. I tried to make loopcuts to prevent wacko subdivision, but failed.
Thx so much!

that diagonal line seems to connect to one of the inner circles, not the orange one you selected. It looks like you have some overlapping faces there. Try redoing the boolean operation and make sure your cylinder is long enough to really pierce the object.

on another note ... if you plan on using subdivision, consider reducing the edges of the zylinder to about 12 or even less. If you integrate it correctly subdivision will take care of the rest. See this tutorial series:
https://www.youtube.com/watch?v=yi87Dap_WOc&list=PLjEaoINr3zgHJVJF3T3CFUAZ6z11jKg6a

the cylinder pierced through alright, but for some reason these diagonal lines keep popping up again. I will try to include more pictures of the steps I took. Thx for helping.

those diagonal lines are there for a reason, blender cannot handle faces with in your case 32+4 edges. therefore it inserts the diagonal lines to reduce the amount to 16+2 edges wich is a lot aswell. so you have to step in an reduce the maximal amount of edges of the faces around your zylinder to 4. subdivision makes a mess of faces with that much edges.

So... I need to use a cylinder with less edges?

either that or insert a massive amount of loopcuts around your big object so every edgevertex of your cylinder becomes part of your big mesh. since you are modeling in low poly reduce the edges of the zylinder. but you have to connect the vertices of the edges either way. onyl with less edges you need to make less loop cuts around your big object.

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


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Is there a way to automatically remove ngons?
As you can see, I am trying to make a computer screen, but am wondering how I can make my mesh of a screen correctly connect to the main frame. Do I have to manually use the knife tool? Or is there a better option? Thanks for all advice or suggestions!
The first picture is the subdivision gone wrong.
The second picture shows my original mesh.

Add to main body as many loopcuts (CTRL+R) as vertices on perimeter of "screen part". Then delete ngons, select edges and create W -> "edge bridge loop".

Thanks! I tried that, but it covered up part of the screen that it connected to. Will update pictures to show problem. See how the screen full of many edges is reduced when I do the edge bride loop? Probably am doing something totally wrong.

Did you try converting your selection to tris and then converting to quads ?

Um no. So I need to convert the selection to tris, then to quads? I thought the default was always quads. Thanks for helping!

Seems you have deleted Ngon not as face but as vertices, thus reduce geometry.

Cut your screenshots only to relevant area please, it's much more complex to preview them when they are that big and containing something not related

From left to right:

Add loopcuts CTRL+R. Number of loopcuts = number of vertices (I marked them with blue dots) except those in the corners, because they already have a proper connection.
Select and delete Ngons: Delete->Faces. Select edges
Press W-> Edge Bridge Loops

Thanks! I was trying to do the loopcuts and edge bridge loops in pieces, whereas you show how to do it all at once. Now it works! Thanks!


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When rendering with GPU Compute, GPU doesn't seem to work that much harder
For some reason, my rx 470 graphics card which is great for gaming and so on, cannot render faster than my intel i5 processor. Why is this? Wouldn't GPU Compute make things run faster. And, if that wasn't enough. My task manager indicates that the GPU's percentage of usage does not go up beyond 2-3% when rendering. I want more of my gpu to be used. Is there any way I can do this?
For example, when rendering this snowman, my cpu took less than one second, while my gpu took a little less than three seconds.. And here is the same render done with the cpu. Notice the time difference. .
I am a little annoyed, since I paid a lot for my graphics card, hoping to do animations. But, for some reason, it just isn't cutting it.

We're going to need a bit more information to answer this question. Which rendering engine are you using? If cycles, what tile sizes are you using? Some screenshots of your render settings would be helpful too.

uh, no. I thought that was automatically done. How do I change it?

Under performance in the render tab of the properties panel.

Okay, I finally found out how to increase the tile size, but the GPU Compute still isn't really that much faster than my i5. I have my settings set to GPU acceleration with OpenCL, and am wondering if I can get anything more out of my gpu. And, the usage is still unrealistically low.

I don't know blender stack overflow very well. Is there a way I can post another picture here?

Just click the edit button at the bottom left of your question

thx. Here are my settings

"Wouldn't GPU Compute make things run faster" No, not necessarily. If your GPU is low end or slower than your CPU it will actually be slower. Also GPU task managers with "core load graphs" aren't really that reliable source of info

First, you shouldn't put text in images - screenreaders can't read the text in an image, crawlers like Googlebot can't index text in images (just write what you would have put in your image, as text below the image). Second, freehand squiggles and freehand text make your images look really sloppy - you probably got downvotes just because of that.

@DuarteFarrajotaRamos In this case GPU compute should make things run faster. If the benchmarks are any indication, his card should be much quicker than his CPU.

Is this a laptop?
You might have a performance throttling issue due to how the power usage is handled if it is.

No, it is a desktop built by myself. Also, sorry for the inconvient sloppiness in the screenshot, but I did my best to highlight what was going on.

Try rendering a higher resolution and see if that makes a difference. Just to make sure, you are using 256x256 tile size for GPU right?

I did. Now the difference between the cpu time and gpu time is 24 and 26 seconds respectively. I did use 256 by 256 tiling

Also, the memory on the rx 470 is only 4gb whereas my computer's onboard memory is 8 gigs. Could that be it?

I just found out that using auto tiling size from an addon made my day. Apparently, there are issues with opencl and amd optimization, the fault being AMD's. But, when I installed the addon, the tile size ended up making a huge difference. Before it was installed, I changed the tile size to 256 but for some reason did not get the same results. I hope this is okay if I figured it out on my own.

Answering your own question is totally fine, and is also much better than solving the question but not telling anyone. Glad to hear you got things all sorted out.

For example people like me :-P... Just thought about (I knew that add on but for some reason in my 2.8 it was deactivated by default and with you post I came me in mind, to enable it...


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Sculpting a photorealistic human face for animation: use the multiresolution modifier?
I'm locking down a production workflow for sculpting photorealistic human faces for animation but having a conceptual problem about whether or not to involve the multiresolution modifier
the sculpt workflow is: character sculpted in actual real-world clay > form captured via photoscan to an ultra-dense triangulated mesh > clean-up, sharpening, additional details and skin textures done in blender > mesh retopologized to lightweight animation-friendly all-quads > wrinkles and details recovered via normal maps and displacement maps plus a subdivision modifier
there seems to be no reason to use the multiresolution modifier in this process - is there a strong reason to use it that I'm missing? - it's a very powerful modifier, it obviously must have some important uses
a related issue: I have sometimes had difficulties with data loss when relying on the multirez modifier to preserve high rez sculpt work, especially when trying to save/restore multirez data using the .btx format - I suspect I'm not understanding the place the multiresolution modifier occupies in a professional sculpt > animation pipeline - can someone clarify?

I think it's kinda opinion based question. I've stumble upon many workflows but one worth mentioning is: Dynotopo sculpt > retopologize > multires and sculpting details > bake normals. This one allows you to have control over LoD and it's (for me) easier to add details. If you've done detailing in sculpting phase there is no need to use multires anymore.

From what I understand about the development of blender and the workflows that are out there, the multi resolution modifier is no longer frequently used, and for good reason. I think it still has uses, but overall it's no longer an essential modifier for workflows such as the one you describe.
The multiresolution modifier was, for a long time, the only feasible way to sculpt in Blender. Manually creating a dense mesh or using the subsurf modifier (applied) was an option, but these are destructive methods that lead to objects that are so dense they are difficult to edit.
With the addition of dynamic topology, there is now a way for an artist to create highly detailed objects without this modifier. In your case, a scanned object replaces this, but the  results are the same: You and up with a dense triangulated mesh, and the workflow you outlined is a great way of turning that into a final product.
Since dynamic topology is much more free from an artistic point of view than the multires modifier (you don't have to worry about topology at all) it's no longer used much for initial sculpts as there are better options out there.
However, the multiresolution modifier still has a place, and that place is in  adding details to modeled meshes. Not everyone is a sculptor, and sometimes hand modeling an object is the best way to go about it. If you then want to add details, this is where the mutiresolution modifier is great. It allows the artist to add details non destructively, and gives the option of baking this detail to maps. Using an applied subsurf modifier or a dense mesh won't allow you to do this, as any detail you add is practically permanent.
Finally, the mutiresolution modifier can still be a good way to sculpt an object from scratch, provided the topology is OK, or you start with a simple model. All in all, this modifier has it's uses, mainly in workflows where a mesh with good topology is the starting point.

I'm learning sculpting myself right now, and I struggled with the same question! However, the multires modifier is a powerful tool and shouldn't be overlooked. To clarify, Dynamic Topology should be used for concepting, and the Multires Modifier for finished meshes.
Dynamic Topology is flexible and easy to use; for conceptual sculpting, it's the way to go. It acts the way zbrush might, and kinda like real life (adding clay to places you need more). However, it's gonna mess up your mesh!
The multires modifier, on the other hand, has the advantage of being able to toggle on and off, and it plays really nicely with other modifiers and vertex data. This becomes more helpful when you have a finished model with nice topology that you want to add detail too, because it's completely non-destructive.
So for your workflow, you might use:  real-world clay sculpt > photoscanned to a dense mesh > mesh retopologized to animation-friendly > wrinkles, sharpening, additional details, and skin textures done via multires-modifier
And then just turn off the multi-res modifier during animation. This would let your details be 'real' geometry, and you wouldn't need the normal/displacement maps. The multires modifier is certainly more powerful/flexible than subsurf+displacement maps, but it's up to you if you need that extra flexibility.

good thoughts, appreciated - I have a concern about doing fine details as actual geometry on an all-quads mesh - to get the same fineness as a triangulated mesh (where faces are oriented organically) subdivs have to be very high (but, hmm, my baked displacement maps are used on a highly subdivided all-quads mesh...)

cont: I'm also uncomfortable about allowing the modifier to hold the fine detailing work - detailing can be a long process - to have that held only by the modifier is worrying - baked textures seem more archival - the modifier is def. useful for toggling the hi-rez version - I wonder if there's there a way to turn displacements into a multirez subdiv level?


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How to select objects by collection from selected objects in the scene with Python?
I just started using python and got stuck.
I found this script which is used to take the selected objects from the scene and add them to a list based on the name of the material.
I should do almost the same thing but based on the name of the collection, rather than that of the material.
Can you help me?
Thanks in advance.
selection = bpy.context.selected_objects
obj_list = []
for o in selection:
    for m in o.material_slots:
        if '_abetemono15' in m.name:
            obj_list.append(o)

More explanations.
Thanks brockmann,
Yes, well it is difficult to explain.
However I try.
I am a designer for a carpentry shop.
In Blender I have not found a way to calculate the quantities of lumber and things like that.
In recent days I have written things like this:

It was a nightmare. In addition to not understanding Python, I also struggle with English. I'm good at Blender but this time is not enough.
However this thing works, but I had to use the materials to separate the types of timber that are used in the furniture.
But this doesn't work because sometimes I have to replace the surface material without changing the name of the material that is related to the script.
Probably the best thing to do is to use collections to group material types, materials for materials and emptys to group furniture.
I found this. But it works without considering the selection on the scene.
selection = bpy.data.collections["Abete massiccio"].objects

Hi daniele! Please elaborate on your goal. You'd like to get all objects in the scene based on the name of the collections their are in? Can you please add an example to your question?

Thanks brokmann, I extended my question.
I'm looking for a way to post the blend file I'm working on ...

Oh, cool. I didn't know about this service. Thanks. Now I have added the .blend file

Sample script based on your collection name.
import bpy

sel_objs = bpy.context.selected_objects

#identify and choose collection union
col = bpy.data.collections["Abete massiccio"]

# create a list requiring both objects selected and in chosen collection
objs_in_col = [obj for obj in col.objects if obj in sel_objs]

for obj in objs_in_col:
    print("Object name: %s \t Collection: %s" %(obj.name, col.name))

Good candidate for sets set(C.selected_objects).intersection(set(C.collection.objects))

@batFINGER Thanks for the tip wasn't sure how to easily convert the lists to allow .intersection().

or o for o in C.collection.objects if o.select_get(True) would be another way.  .... avoids using multiple in checks.

It works! You saved my life.
I could never have thought of this.
Thanks a lot Ratt.

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


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Change resolution/samples via python when executing it via console
I can't change Cycles's render samples via python when executing it via console,
I'm using this script and nothing changes at all:
script.py:
import bpy

resolution_x = 1023
resolution_y = 1025
samples = 32
format = 'JPEG'
JPEGQuality = 90

bpy.context.scene.render.resolution_x = resolution_x
bpy.context.scene.render.resolution_y = resolution_y
bpy.context.scene.cycles.samples = samples
bpy.context.scene.render.image_settings.file_format = format
bpy.context.scene.render.image_settings.quality = JPEGQuality

On the cmd:
blender -b -P script.py file.blend -noaudio -E CYCLES -o outputrender -f 0 -F JPEG -- --cycles-device OPTIX
Then the console says its rendering 0/196 samples, and its using about 3gb memory so its 4096x4096, both of those values are the default on the file.blend...

Argument order matters to blender and you need to put the -P script.py after all of the arguments meant for the render engine, except the --cycles-device

I attempted that without any different outcome


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VSE Fade audio in and out
I have followed a few hints for this but I'm baffled.
I want to be able to fade in/out audio. I have seen that I can switch on automation, and I can, by using the little diamond indicator by the volume control on the strip panel. But I can't do anything with it.
The manual says I could "Add Fades" using RMB from the sequencer timeline, but there is no Fades option.
The little diamond lights up, has no obvious control.
Any clues gratefully appreciated.
Image follows shows the VSE View menu with no Show F-Curves option.

In the View menu, switch on Waveforms and F-curves.
Select the strip.
In Add menu, select Fade - Fade In Out
(Alternatively right click in the Sequencer area and select the fade options there - here is also an option to Clear Fades)

Gif:

If you want to animate with the diamond, first set the value then click the diamond, so it is filled(you set a key-frame). Having the f-curves visible makes it much more visible what happens. Alternatively you could change ex. the File Browser area to Graph Editor:

Thanks... but I don't have the option on the view menu to show F-Curves! Instead the view menu is subtly different. I shall attempt to post a picture.

You need to update the the latest 2.83+ version.

Argh. Newbie error. - though I had updated and had both 2.8.0 and 2.8.3 installed. Many thanks!


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How can I make a shader or change the scene lighting to make glass less reflective?
How can I adjust the lighting and create a glass shader to make an object less reflective like these:

I tried this:

But it doesn't reflect at all:

What you want is not clear, do you want to create a more reflecting glass? Because it looks like what you've done is not reflective at all... By the way don't use a Diffuse node, only mix between Glass, Transparent, Glossy...

Yeah, not too reflective, not too non-reflective.

I think the basic node organization for glass is a mix between Glass and Transparency. The more your mix will tend to Transparency (Mix Shader value) the less it will be reflective. The Glass Roughness will make the glass more polished.
You can mix that with a Glossy Shader with a Layer Weight as factor if you want to add reflectivity on the normals for more realism, and same thing, play with the Layer Weight value.

By following your shader I get this: https://photos.app.goo.gl/94vkpDyG2o7oono58. There are 3 suns in my scene with a strength of 2, 3, 5 respectively.

so as I say you need to play with the values  ;)  more transparency for example


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Displacement Looks Different in Render compared to Viewport
I am trying to do a simple electricity plasma (lightning) simulation using displacement modifiers. It looks completely fine in the viewport but completely wrong in render.
Not only that, but the light is not working as expected either.
You can see the image on the left is the render of the model with the viewport on right. It's lit correctly and the displacement modifier looks right.

I have checked that all the elements are set to be available for render. (eg displacement modifier is on)
The displace modifier is working - just not correctly. It should look like the viewport.
I also turned off the new feature "light tree". That also made no difference. The Render settings are the exact same as for the viewport.

I'll prepared a bug report but I am absolutely mystified.
Edit: Note the difference lighting is due to a glass face I had hidden. The main thrust of the post remains an issue though.

hello could you please share your file (with just the lightning object)?

Hi yes. Note the edit in the main body:
https://www.dropbox.com/s/wcz9s0d3cbuwm8c/Test%20Lightening.zip?dl=0
Also note I tested this in 2.83 and the problem occurs in Cycles but not in Eevee. Eevee looks correct. In 3.4.1, the problem is in both Eevee and Cycles.

You've activated the Motion Blur option, it leaves a traces that makes the lightning render look different from the preview, so either change the motion blur settings or disable it?

I reported this as a bug and got a similar response. That does indeed seem to be the issue. The reason I missed it is because the animation shows the arc as much much thicker. I was rendering a single frame to check. It's possible to turn off motion blur for just that object (something I didn't know before).

Only report a bug if you're about sure that it's a bug, or at least wait for the answer in Blender Stack Exchange  ;)

I was pretty sure it was a bug, but you are right I should have waited here. The relevant information is here: https://docs.blender.org/manual/en/latest/render/cycles/object_settings/object_data.html#bpy-types-cyclesobjectsettings-use-motion-blur
I think this relevant to my situation: "Warning
An object modifier setup that changes mesh topology over time can not render deformation motion blur correctly. Deformation blur should be disabled for such objects. Common examples of this are animated Booleans, Deformation before Edge Split, Remesh, Skin or Decimate modifiers."


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Copy Rotation to Only Z Axis Not Working as Expected

I'm trying to get the selected ring in this picture to only rotate on its Z axis whilst tracking the lower mounting to the leg.
What should happen is that the ring rotates so that the hydraulic, which is targeted to the UV sphere mounting on the ring, has the least angle - ie has shortest distance to the ring. The idea is that I am trying to make model look like the ring is driving leg rotation and the pistons (there will be 3 or 4 of them) are driving extension and flexion.

The closest I have come is using the constraint "Locked Track". The fixed axis is Z, and the only version that seems to work is -Y. Testing it, when rotating the armature bone in pose mode along the Z axis, the ring should hardly move, but it spins almost 180 degrees.

Copy rotation does not work either.

I have tried damped tracking, and track to. Neither work, but they aren't right for that job.

I tried using two locked track constraints and that didn't give me the results either.

I tried parenting an armature to the "bone" - not an armature but a metal model bone connecting the leg with the hip joint, and then taking rotation info from that, but that did not result in what I was looking for either.

What I am looking for is the world rotation of the lower mounting (called rivet v2 in my blend file) to only affect the local Z of the ring so that the parented hydraulics rotate to the shortest distance. It's proving to be extremely tricky.

I am not sure what you are looking at, but I clicked all the answers that helped me, or even the ones that contributed to my finding the solution myself. Some of them didn't receive answers, and some didn't help.
Edit - actually there are couple of questions I received responses that I did not mark up.

You can Upvote answers and comments that you find useful, but you should ACCEPT (using the tick mark) any answers that directly solve your problem (one answer per question).

unfortunately we don't see the picture with the selected ring anymore...

Where can I find the tick mark? Sorry about the lost image...I'll try to fix.

thanks for editing your question. But honestly - i still don't get it how the movement should look like. And because you didn't get any answer in 5 hours i think other people are also struggling. So i would suggest to improve your question by a sketch/picture who clearly show how the movement should be. A picture explains more than 1000 words...maybe 2 or three pictures with a different angle of the leg and how the ring should be?

Yep, I was looking at it as well, downloaded the file and stared at it for a while... I have no idea, what movement is the goal. :D

Ok I'll have another go in the morning. The closest I can get to the movement I am looking for is with Locked Track, Track Axis = Y, and Locked Axis = Z. With the Target "Rivet v2", and setting the influence to 0.2. I am trying to get the highlighted Ring to only rotate along the "Z" axis so that it follows "Rivet v2" with the least rotation. It does do it correctly for part of the rotation, but then it spins around nearly 180, causing the hydraulics to twist. I just want the rotation inherited by the Rivet v2 from animation to be transferred to the Z axis of the Ring.


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How to simulate movement of rollers
How can a simulation smoothly reproduce the movement of a box on a conveyor. The model described below will simulate the movement, but as the box moves from roller to roller, the box jumps and the rollers do not behave smoothly.

What solver settings or model setup will improve the simulation.
Details:

The rollers were added by creating cylinder meshes. Each cylinder was setup as a rigid-body simulation with mesh collision shape.
The box was added as a cube that is subdivided several times. The box is setup as a rigid-body simulation with mesh collision shape.
The simulation was run, with the results shown in the animation above.

How can this simulation be made to behave more realistically?
The Blender files with this simulation is here -
This question is based on trying to answer this question - Animate Individual Vertices w/ Geometry Nodes - using simulation rather than animation nodes.

Per the accepted answer, changing the collision shape to box fixed the issue.

just change the shape to Box and it looks really smooth

Might be a good idea to change the rollers to cylinder or capsule as well.

What was it before, if not box?

It was mesh before

That worked great! Is there a reason why the mesh had issue but using a box fixed it? It seems like they should get the same result.

I think they can but then you have to mess around with all the settings in there…the Box makes it easier for Blender to calculate. That’s why it „seems“ to be more stable.


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Vertex Painting not showing up
Hey all I am a bit of a blender noob and am trying to figure out why my painted vertex color is not showing up. I have created a Material and created a vertex color node in my shader graph with the col object that shows up as the default after painting but when exporting to unity or viewing in object mode I do not see my color, I do see it as colored if I render in blender. Any ideas ?

If you want to see it in Solid mode, click that arrow to the right of the Wireframe/Solid/Material/Render buttons and change the Color option to Vertex.

That's pretty cool, I can see it in object mode now but it still isn't appearing when exporting it to an FBXand placing it in unity :/


text:
Rendering opengl image and then saving to a filepath
Need help solving how to render an image and then save to a filepath while in a loop.
The following takes a photo and exports; however it isn't rendered.
sce = bpy.context.scene.name
bpy.data.scenes[sce].render.filepath = 'filepath'+str(i+1)+'.png'
bpy.ops.render.opengl(write_still=True)

What needs to be changed?

Hi and Welcome. Too many options... please edit your question, post the complete loop and add your actual requirements. For one, you can use the scene in context to set the path bpy.context.scene.render.filepath = "rndr_###.png", next you would have to set the frame using bpy.context.scene.frame_set(#) within the loop, see: What is the Python script to set the current frame and finally you might want to reset the output path. Also, I recommend take the tour to learn about how this site works: https://blender.stackexchange.com/tour thanks.

Um, I think we've all been concentrating on the wrong part of the question and not "however it isn't rendered."  If that's the real question, the answer is that the OP is choosing screenshot mode rather than rendering.  Voting to reopen.

Editing the question the way it makes sense to you is slippery slope, I asked for clearification 10 hours ago, let's wait for the OP. @MartyFouts

Undoing an edit that makes sense is more pretty far down the slope.  Pretty clear "it isn't rendered" was part of the question.

There you go, a compromise.  Emphasized a point we all missed but didn't add an interpretation.

@brockmann didn't you vote to close the question as a dup?  That hardly sounds like waiting for the OP to me and strikes me as no less interpreting the question than my edit.


text:
multiple textures for multiple objects in a single file?
its been a long time since I tried to make anything for online communities that're driven by personal avatars, and I don't remember it being this difficult to put textures onto a group of objects just so I had a good visual reference to make sure everything lines up as expected.
the problem; I have a set of objects [3] that sit together, a head, a body and legs, when I go to put the texture onto the upper body then switch to the lower body to put the texture on that as well, it just has the texture that the upper body has and I can't work out how to make it display both textures in; 1: an editable state, 2: shows both at the same time
I don't need to be able to 'seamlessly' transition to texturing one or the other, I'd just like to see how they both line up so my models don't have awkward seams. without making my own model from scratch I can't alter where these cut off lines are either. I'm certainly more of an artist than I am a sculpter!
both images are loaded into the 'texture slots' section, it just only appears to handle the last one picked as the texture for all 3 parts of the object, and I can't quite work out why.

You need to create 3 material slots for your merged object.
In each material slot put a material with the texture for one part of the body.
In edit mode, select a material slot, then select the part of the body that it matches, and click assign.
That will assign a different material to each part of the body and you can put the different textures in each part.
Here's an example.  I've already assigned materials to the 'head' and 'body', and have selected the 'leg':

Before:

After:

For my materials I simply used principled shaders, but you can make each material whatever you want it to be.  Here's a 'body' shader with a musgrave texture:

and the resulting object:


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How to set density(no. of particles per area) of hair particles with weight paint?
I want to create a fade hair style but using weight paint affects the length of the hair not the actual density.

@cegaton it's working for length but not for density.


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as of blender 3.2 what is best way to go from slow rug particles to Realtime texture?
I rendered this:

which up close looks like:

But it is intended for indoor house in game engine. Specifically isaac sim as it's for robotics, but think of it as Eevee, Unity, Unreal, etc game PBR material.
Obviously I cannot just take a top view render and keep as albedo, as lighting and shadows and camera angles will all look terrible.
But how can I 'generate' a texture with AO, roughness, color, and normals and heightmap to make a believable render that would look similar to if I rendered the scene with the actual particles. Also of course it should be tileable, but with eg one tile filling up about 2m square.
What I have rendered is just simple particle system with 1000 particles and 1000 interpolation, so 1 million particles.
Question: How do I go from here to get a game-ready pbr texture map, with option for AO,roughness, normals, and heightmap for parallax occlusion mapping?
(also note that being for robotics, there is likely to be a camera fairly close to the ground so it's important that the texture look believable from low hights. ie imagine a 12 inch tall teddy bear running around in a carpeted house in a video game. how would I get that kind of effect in realtime. Most carpet textures I see are 'industrial' style like at a hotel, where they are very flat and not like the kind usually found in homes that are fully carpeted, eg 1.5cm fibers.)
RESULT: based on answer below:

Try something like this - I've done my best to label the appropriate maps. I must point out that a material such as this is not ideal to create in blender, as blender's shader system does not handle Parallax Occlusion Mapping nor Tesselation natively. Because of this, I used a heavily subdivided cube (in cycles) as a basis for displacement to try and "approximate" the effects of occlusion mapping - you can just use the B&W map used as it's input for the height map (not worrying about the displacement node).

wow that's really nice. I tried to replicate it but mine is not displacing. I subdivided my cube into 6 million vertices.  I updated my question with my result. maybe can you share you blend file?

Under the material settings, there are 2 places you can enable true displacement (they "hid" the second one) - one is under "displacement", the other is under "settings" below it (you have to expand the menu) - change where it says "Displacement: Bump Only" to "Displacement: Bump and DIsplace".

marking this answered though it didn't actually answer how to go from particles to maps but i guess that isn't really feasible, and this answer really helped

Yeah, sorry about that - I don't know if I can "answer" that per se, but as far as I know particles to maps is not possible - I don't think any kind of (texture) co-ordinate data exists for particles until they are realized.


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Texturing multiple chessboards
Let's say I'm going to be doing an instructional animation showing 100 different chessboards/positions (all at once, at one point). The chessboards are just planes of 8x8 faces.  The pieces will just be textures.
My question is how to structure the materials.
Originally, I thought of having all the 12 piece types on one image, and using a separate UV map per chessboard, and if a queen was at c3, then move 'c3' in the UV map to be over the queen.  However, this turned out to be rather messy, and not maintainable so I'm starting again.
The "brute force" method is to do all the work in Gimp and have 100 textures of a full board.  That is of course not efficient with 100 1024x1024 board textures.
Another idea is to use a different material per 'face', so then have 14 different materials (6 piece types 2 colors, 2 blanks)  and apply a different material to each square.
Note that I would also like to be able to show different positions on the 'same' board at one point, so having some way to animate between different squares having different pieces is a goal.
Is there an obvious way to do this that I'm missing?

Texture the board with a checker pattern. Create your pieces/mesh individually.

@cegaton this is the correct answer. I've tried several things and this is the most obvious way to just easily switch between the pieces. If you add it as an answer I'll accept it. Otherwise I guess I'll add my own answer.

It seems you are trying to do illustration work on a 3D modeling tool.
Inkscape could be a much more adequate program for this. You will get the additional benefit of clean, unpixelated vector graphics.
If you want to do it in Blender then I'd say take advantage of its powers.
Model a clean board as a separate recyclable object. Texture it using a procedural checker texture as Dontwalk mentioned (one less image texture and unwrapping needed); then duplicate it around your scene as desired.
Then model your chess pieces also each as a separate recyclable objects and place them on each board instance at the planned position; even if they are just a bunch of simple flat planes or circles.
You can take advantage of easy independent positioning for each, and use snapping for precise placement, no need for dozens of different textures. You can still use image based textures for each piece if you prefer, but taking advantage of modeling might produce better results depending on what visuals you are looking for.
This way, you wont have duplicate textures, needless duplication of information and manual work painting each scenario as a pixel based image in a painting program.
If you are looking for plain flat colors and simple visuals you might not even need formal rendering and can quickly capture images directly from the OpenGL viewport preview.

Thanks.  I'm visualizing how to represent the chessboard to AlphaZero (chess AI) which uses Convolutional Neural Networks, which take 'stack's of images as input.  So in fact it's better for me to use 'images' for the pieces instead of separate objects, and at some point they transition from images of pieces to just 'on or off' squares.

Again, I really need it as I stated in the question, which is for there to be actual image textures on on the plane, not separate pieces.  And that's why I can't figure out a good way to manage the textures in that case.

Can't you extract the images from the above setup or similar at the end? You can still make all your textures in GIMP map them to individual textures and then do all the setup in Blender.

I see your point.  The thing is half of the chessboards will actually end up being a 'all black' 'board' with someof the squares/pixels white (the full square). Think, 8x8 pixel image with radom black/white squares. Circles won't have artifacts with two adjacent pieces, but squares most likely will. I may be able to get away with quite squares that are slightly smaller than the black surface 'square' hey occupy


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Dark artifacts while rendering
I have tried recalculating the normals, added an Edge split modifier and tried the Subsurf Modifier too, but none of them seem to remove the dark artifacts around the edges.
Increasing the transmission and glossy bounces also have no effect.
Please suggest what I can do to remove them.

your normals are a mess. You need to make normals consistent.

I made the normals consistent, and checked to see that there were no Split Normals. I still see the issue.
Can you have a look at the blend file here?
http://pasteall.org/blend/index.php?id=49154


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Wrong camera pose with respect to scale of objects in the scene
I am using the urban canyon Blender scene "Multi-FoV" Synthetic dataset from University of Zurich to create camera trajectories.
However, I see that the camera pose given by Blender doesn't match with the actual motion of the camera with respect to the scale and dimensions of the remaining objects in the scene.

Can you elaborate on what the question is here?  A link to the data-set, the results you are seeing (and how) vs expected result.

Here's the link to the dataset
http://rpg.ifi.uzh.ch/fov.html


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Humanoid Rigify help: I tried everything but still getting: Warning: Bone Heat Weighting
I know this is a duplicate issue, but could someone help me to understand why I'm getting this Bone Heat Weighting Failure.
I've gone through the forums and youtube and tried around 8 or so different suggest fixes, but no luck.
I'm fine with the module being one mesh. I've tried loosening vertices and I noticed it broke the mesh into parts with the finger and toe-nails separate. I'm not sure if this has anything to do with the issue but I'm certainly fine with that all being one mesh.
Here's a couple different links to download my latest file post fix attempts:

or
http://pasteall.org/blend/index.php?id=48571
or the same via google drive:
https://drive.google.com/open?id=1h5clTGbx5VgVXsM_of0sWlLiA1JV-adi
Also, if it's helpful, here is a blender file with the metarig before I generated the rig:
https://drive.google.com/open?id=1J7K-05I6SjhW6dz2TkWKgoT3RJXrzX0W
If it turns out the issue has something to do with the fact that I deleted the meshes for the eyes and inside of the mouth. Here's the original model I was using:
https://drive.google.com/open?id=1xFYN7ueDiSUrRH8BI1XkZPzgifNrJ5yq
I simply deleted all the extra meshes to try and simplify my issue. Ideally I want to work with those other meshes and rigify, but I'm starting out simple.

It may seem trivial but ,for uploading .blend files, I would recommend using http://blend-exchange.giantcowfilms.com/

Thanks! I uploaded and added the link to my initial post.

I haven't got it completely solved, but so far, I found that removing the fourth and fifth fingers of the foot removes the error.

Interesting @Allosteric you removed the whole fourth and fifth fingers? as in you just cut them off lol?

I am not sure what is problem but I face this issue mostly when object has non uniform symmetry  while applying automatic weights so if u can make your object symmetrical your problem may solve


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How to make a slice in the Particles System?
I am a student looking at microstructures. Therefore I am using the Particle System to create a lot of droplets.
To mimic a microscopic image I want to make a slice of the system.
I can do this by using the shortcut Alt+B. (see image)
But by using this shortcut, rendering isn't possible.
Does anyone know how to make a slice of a Particle System?  The Boolean Modifier, Knife tool or Bisect don't work for the Particle System...
Thanks!
Jantine
By using nodes, I get black artefacts:

Suggestions for a solution? I guess these black shapes are remaining of part of the balls that overlay each other, which is also something to solve...
Thanks!
Is it possible to fill these spheres? So that the inside is solid green?

Thanks!

Try increasing amount of transparent bounces in the Properties editor > Render tab > Light Paths rollout > Transparency until black spheres disappear

Hello. It is advisable not to keep a thread going by adding follow-up questions to your original one. Your follow-up would've been  better added as a comment to my answer. Anyway, what you now request is possible although a bit more computationally expensive in my suggested node setup. It requires using the volume shaders. I don't have time to work on an example right now, I'll probably do it tomorrow and add to my answer.

If this is your intended result (full slices, not hollow) and you don't need to animate the particles, a different route can be followed that involves "making the duplicates real" and Boolean modifiers. I'll probably post a second answer with this route.

I would appreciate that!

You can slice them at render time (i.e. the full geometry will still be there, but only the relevant slices will be rendered) by using Material nodes:
Say you want to render only the portion 0.5 < Z < 0.9. Then, as your sphere's material, use a Mix shader:

The Mix Shader should be used to mix your material (whatever that is, e.g. a green Diffuse) and a fully white "Transparent BDSF".
The mixing "Factor" is either 0 or 1, controlled by a set of "Math" nodes that check whether the "Z" coordinate is in the desired range.
Result:

Note (after your edit): if there are many particles, the "Transmission" value under "Bounces" in the "Light Path" Render settings should be at least twice the number of particles that can be found along a lightpath from your point of view. ← If this doesn't make much sense to you, just increase that value until it looks right.

Another (less flexible) method would be to use camera near/far clipping.

Thanks for your answer! But I still have some problems with this. To which object are all the nodes in the node editor added/linked?

The one showed is the Material Node structure for the "sphere" object. (I assume that you have a single sphere that gets duplicated by the "rendering > object" option of the particle system. That sphere must get this material)


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Mist Pass not Respecting Certain Materials
I have a complex scene that I have broken down to render in 3 layers, but in order to do a mist pass (needed to help control light), I am rendering the full scene on CPU in cycles with 1 sample. The pass renders, but some materials or objects are not being respected correctly by the mist pass.

As you can see some elements in the scene are showing as white. I have looked at the materials and I can't see anything particularly special about them. They are hair meshes (not particle system) and they have fairly ordinary PBR textures applied. Ray visibility is on for each of the offending objects.
I'm stumped. What could this be caused by? This doesn't feel like a bug but something to do with controlling an object's effect on a mist pass.
Update, ok so it turns out that any material that has alpha information to control opacity of textures causes this. I guess this IS a bug....unless it doesn't matter? I think it will...depending on how its composited.

Probably if you can share  your scene setup with just a single issued object ... so we can check, because it is not happening with my version, so it could be a bug. BTW I'mnot sure if I'm uptodate, but Mist pass is (or was) an issue to represent semitransparent pixel in render ... for that people use simple gradient shader under View Layer Properties > Override

Thanks for your comment. That's very very helpful. Could you give a little more detail? How do you use material override? If you set that does it simply ignore the materials for the mist pass? If so that would solve this issue. If it does, it really ought to be on by default don't you think?

To keep it organised here - share part of your scene (as suggested in my first comment) or delete your question and create a new one. We can't answer it (or close it as a bug) right now. Thank you ... Mat.Override has to be rendered as separate image for compositing (it overrides all materials for such render) so it is not the same like a mist pass, that can be composite in a single render run.

BTW since your hairs are a lot of overlapping meshes ... this is probably your issue https://blender.stackexchange.com/a/38113/2214 ... speaking to my semitransparent pixels see this answer https://blender.stackexchange.com/a/277370/2214 ... or just search on this site "mist" there is plenty of questions about this topic.


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Add an image to an existing HDRI
I have an HDRI I am very happy with in a scene, but I want to add an image - specifically a moon - to the sky so that as the camera pans around my object the moon comes into view. I've rendered it out as a plane in the sky and the moon looks fantastic but does not retain its position relative to the sky.
I could try setting the moon a long way back and making it big, but I don't think that will work either.
What I want to do is add the moon as an image texture overlaying the HDRI in the world settings, but it doesn't work simply to do that. There is clearly some special sauce required. Is it possible and how?

The issue is similar to this: Add a panoramic background to scene in Cycles
However, I can't make the image equirectangular.

I think you could get a better result if you do this on a photo editing app.

I'm not sure I understand why "overlaying it over the HDRI doesn't work". You should be able to get an image of the moon and composite it over you sky fairly easy. Show us what you tried and maybe we can tell you why it isn't working.

Yes, I have thought about doing it GIMP or something, but it'll be a bit awkward and I'll have no control over the moon's placement.

"I'm not sure I understand why "overlaying it over the HDRI doesn't work"". The camera swings around quite a lot. The camera originally starts on the port side and swings around underneath. The Dirigible is also moving on a nurbs path and the camera tracked to the dirigible. Because the moon is not on the same plane as the HDRI, it doesn't move naturally as if it were part of the sky. Compositing an image of the moon over the HDRI  in the world shader area does not work. There must surely be a way to make it work.

The (partial) answer is to create an equirectangular image with alpha in an external editor such as gimp and bring the image in as an ENVIRONMENT TEXTURE, not as an image texture. You can then easily overlay the image on to the original HDRI and set up its own texture coordinates moving it around.
However, you won't be able to scale it and I am currently having problems trying to get GIMP to "map to object" in filters in order to map it to a sphere so that it does not distort when displayed as a world background. For some reason "map object..." is greyed out in GIMP and I am struggling to find a way around that.
But that is the solution I was looking for and I hope it helps some one else.

You could do this in two ways: either an object in the 3D scene, or an image node in compositing. I guess you did one of the two in order to get your current result.
3D Scene
In Blender 4.2, you can add an image mesh plane via the menu Add > Image > Mesh Plane. Before 4.2, you would have had to enable the addon Import Image As Planes, then use the menu Import > Image As Plane.
While browsing for the image to add, check your shader and alpha settings. If you don't want the image to be impacted by surrounding light and receive shadows, use shadeless or emit instead of Principled.

Then if you want your image to always face the camera, you can add a Track To constraint, targetting the camera object:

Then to have the image follow the camera as it moves, parent it to the camera. Select the image then ⇧ Shift select the camera and hit ⎈ CtrlP Set Parent To Object (Keep Transform).

Then you can move the camera around with the object following it, while being able to move it around yourself if needed.
Compositing
Using the compositor, you can add a mix node with alpha enabled, plug whatever your background is as first color input, and your image as second input. Then add a new mix node, plug your foreground as first color input, and your background + image as second colour input, and you might need to make your own factor to properly merge them.
Here i used the Environment pass as background (I used a nice Nishita Sky texture on the world shader), then reused the Env pass with a Greater Than math node to get the mask for the second mix node.

No, sorry. I am quite familiar with overlaying images and other movie images in the compositor as well as adding images in the 3D space. Neither of these will achieve what I am looking to do which is to overlay the moon in the WORLD environment. The issue is, that as the camera moves, the moons perspective in the camera needs to be the same as the rest of the HDRI image. I do indeed have the image in the 3D environment for this image and the planes Z access tracking the camera. But the moon moves around in relation to the HDRI image instead of being part of it.


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Cycles Textures not showing with shading - Works in Eevee

I think this must be some simple thing that I have missed, but I can't get this model to render properly in Cycles, yet it works perfectly in Eevee. The cycles version is not rendering with any shadows or texture. I'm stumped. The textures are jpeg - I am wondering if that might be it?
This is bound to be some simple thing - does anyone know what it could be?

Hi Susu, thanks for the response. I will do as you suggest later today, however the shaders were set up in a "standard" way, and its the CYCLES version which is not responding to light - ie as if the images were emitting. The Eevee version is the one on the right. The model has image textures for colour, metallic, normal, and an alpha. Importing the shaders, the alpha from the image shader was plugged to the alpha of the BSDF, where it should have been the colour. Disconnecting had no effect on whether cycles shaded the model or not.

As per susu's request here is the node set up. This is pretty much how it came with the FBX. The only thing is I tried converting the jpg to png and re-importing the image for the texture colour. If I remove the colour image texture, the shadows and lighting are working correctly and the normal map is also working. The alpha map is also working. I am completely stumped....it all works PERFECTLY in Eevee - it's gorgeous model even if the colouring is a little rudimentary.

please edit the question with the info, don't add it in comments, some users do not read comments.

Do you have any lights in the scene? Seems like the image on the left is lit only with the environment, so there is light coming from all directions making the image have no distinct shadows.

Ok - noted about updating any new information in the main text. I didn't really have much - just other stuff I tried. To answer your question, lights were the first thing I tried experimenting with. Also adding in an HDRI and environment lighting. It is definitely something related to the image texture. I'm puzzled as to why it works fine in Eevee but not Cycles.


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Cycles not Showing Shadows Correctly - Works in Eevee
This is a follow up to this post:
Cycles Textures not showing with shading - Works in Eevee
This is a similar problem. For some reason the translucent shader is not working properly in cycles:

Note, from left to right, it is Eevee, Cycles with the same light settings, and then Cycles with the point light turned down to 1W and no environment.
I have mixed translucency with the BSDF principled shader a more diffuse effect from the particles but it is acting a bit like a weak emitter. Also, you can see that the lens of the eye piece is emitting as well. There is no translucency set for that - it is just a simple image texture and principle BSDF shader. It ought to be completely in shadow.
For absolute sure, I am missing a simple setting somewhere. The Eevee version is what I ought to be seeing, but a little bit more realistically in cycles. What am I missing?
PS...I don't know if it is related, but Cycles is also ignoring the background when rendering. It is displaying a white background. (Blender 2.91.2)
Edit - I created a new blend file and appended the collection. I could not get the background to work properly in the original blend file. Once imported into the new blend file everything worked as expected. If any one knows if there might be seetting - I leave them to answer, otherwise the solution is to reconstruct the blend file.
Edit 2 - I have subsequently worked in the new file and attempted do use the same process. I added simple shaders to a low poly object, and in cycles it is not displaying the lighting correctly. The hat that I brought across IS displaying correctly. Again in Eevee, the new object (a boot) is displaying correctly. I cannot figure this out.

The answer to this is the "Ambient Occulsion" option in the world settings. If this is switched on, it is displaying the object "incorrectly" from the POV of what I would expect. Obviously, Eevee and Cycles handle AO differently. If anyone has anything else to add I would appreciate it (trying to learn here), but otherwise this was what was the cause of my issues.

Ambient occlustion is a way of fake shading to aproximate shading close to where objects touch each other. In cycles there is no need to fake shading as it the engine tries to resemble the way light works in the real world and the shading is calculated by how light rays bounce on the scene. Ambien Occlusion in cycles can be used though to simulate dirt and smugdes.

@susu There is an "Ambient Occlusion" setting in the World properties that can be used to uniformly (and not realistically) light the entire scene. Though there is a "Distance" setting (which can be negative) that somehow has an impact on contact shadows

Thank you both. Susu - you recall the previous post about this - this would have been the same problem. Is there a default setting different in the way Blender handles world settings from previous versions? Because I don't recall having this issue before recently. I think Ambient occlusion got turned on for Cycles when switching to Eevee...I guess I'll have to check. I now know to switch off AO for world settings in Cycles. Phew. This really had me tearing my hair out.


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Can I keyframe the position of an image texture node on the surface of a model?
I'm trying to keyframe eyes on a model but the eyes are image textures on a surface. Moving the surface that they're on doesn't work. I just need a way to move the eyes (images) on the surface. changing the position of the original 3 images (alb, nrm, and tcl images) without editing the images so I can animate them
Eyeballs wont work because they wont fit the eye holes.
Here is a screenshot.
Let me know if more info is needed.

Yes, you can animate and keyframe image texture movement.
First you need to create a UV node and connect it to your image nodes. That way all of them will use the same coordinates. After that you can add a Vector math node between those two and change the x and y values to move the eyeballs.
Once you are able to move them using those values, you can also add keyframes to them.

ok i did this and looked in the graph editor to adjust the curves but they werent there. is there another way to modify the keyframe animation?

The node called Normal has 2 balls. You can move the top one to move the eyes and add keyframes to it

There are multiple ways you can animate movement of a texture on a plane. Here is the most direct:

The plane is already UV unwrapped.
Change the image mode from "Repeat" to "Clip".
Set your keyframes on the X and Y values in the Mapping node.  Changing these values moves the effective position of the image on the UV Map.


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scultpure changes every time I try to paint
so I am new to blender and I have been trying for days to get vertex paint to work on my sculpted object. Ive followed multiple tutorials but it just wont show up.
UPDATE:so now I am able to draw on my figure but I edited my character more in sculpt mode but when I go back to vertex paint mode the edits get undone and it reverts back to the old character? But then its back to the new character when I go into sculpt mode again
I am also using blender 2.931
thank you
here is my file sorry I dont know how to upload it properly
https://drive.google.com/file/d/1QP-lvnOZG2e6pbGRKcq46lyGpzp6ZuXC/view?usp=sharing

Can you please share your file as well?

Don't update the question with a totally different content once your first question was cleared up, it creates a mess since it's not clear to other readers what were you asking from the beginning and what other people were answering to. Ask different questions instead

oh ok sorry about that

I can see that you have the faces in the upper right corner enabled:

This works kind of as a mask.
You can disable it.
If you want to use a mask, then

switch to Edit mode
select the faces that should be affected by the paint brush
switch back to Vertex Paint
now only the selected faces should be paintable

Probably you have selected none of the faces and therefore you can't paint anything.

Yup. In this mode if faces aren't highlighted, you can't paint on them

Thank you so much I would have never though that was the problem but it works now thank you

One more thing, I edited my character more in sculpt mode but when I go back to vertex paint mode the edits get undone and it reverts back to the old character? But then its back to the new character when I go into sculpt mode again

Hmm, that behaviour sounds really strange. Do you have any modifiers active for your model?

Im not sure how to check that sorry, I uploaded my file if thats any help

Answer to your second question:

In the properties window in the modifier tab I found the Multires modifier. I never worked with that before, but as I can see there is a different value for "level viewport" and "sculpt".

Set the "level viewport" to the same value as "sculpt" and then you should see no difference any more when you switch between these modes.

this worked thank you so much for your help I appreciate it!

Actually there is one more thing im sorry, the object still reverts back to its old form when I go into edit mode. And when I go into object mode its fine, it shows the new version, but then when I edit the object in object mode and go to vertext paint it goes back to the version before I edited it in object mode

I was trying to reduce the amount of vertexes in object mode and I had to select the object for that but when I am back in sculpt mode I guess the object is not selected?

Some modifiers don't show up in the edit mode, because usually you want to edit the original mesh. However a lot of modifier have the option to be displayed in the edit mode - this one doesn't have this option. I you want to see the new version in the edit mode you could apply the modifier, but then the window with the settings(first screenshot) disappears.


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Liquid Stabilisation?
After recently starting liquid simulation, I wanted to know how to stabilise the liquid after it is poured into another object(collision object eg. cup). No matter how many extra frames I give it, there is always some jittering happening and the liquid keeps moving.
Thanks!

can u provide blend file?

Animate the flip ratio and set it to 0 at the point where you want the liquid to start settling down.  The flip ratio changes how chaotic the liquid behaves.  You may also want to play with viscosity and diffusion, depending on what kind of liquid you're trying to get to settle down.

You could also use the APIC fluid method as it is calmer and better for realistic animations


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How to apply one pose after another via scripting?
I have 3 poses: Default , Location , Rotate & I need to execute them in that order, like this:
armature.pose = armature.pose["Default"]; #1
armature.pose = armature.pose["Location"]; #2
armature.pose = armature.pose["Rotate"]; #3

but this does not work, instead whatever pose was selected manually before running the script it seems to be going from it to Rotate
For example if Default was selected manually and then the script was run, this is the pattern it follows:
Default -> Default
Default -> Location
Default -> Rotate

The output of this is that it shows only rotation change

Whereas it should be:
Default -> Default
Default -> Location
Location -> Rotate

The output of this should be that it changes location then rotates

What do you mean by 'execute'? Poses are static positions.  Are you trying to generate an animation where Blender uses interpolation to move from one pose to another over many frames?  You need to move to a frame, set the pose, keyframe the pose, and then move to a later frame and do the same thing with the next pose.

I may have come up with a pseudo solution:
armature.pose = armature.pose["Default"]; #1
bpy.ops.screen.animation_play();
armature.pose = armature.pose["Location"]; #2
bpy.ops.screen.animation_play();
armature.pose = armature.pose["Rotate"]; #3

but I'm not sure if it will work everytime


text:
Prevent rigid bodies used as particles from going through each other
I'm a student looking at microstructures of foods. I created an 'emulsion', but the droplets 'go through' each other. See image.

The image shows a rendered slice of a box filled with balls (after simulation). This slice is very thin (0.02 in BU), so the overlap is not caused by different depth of the balls.
Does anyone know how to solve this? The balls are rigid bodies in a particle system.
Jantine
Rigid Body and collision settings for the 'source' object for the particles system:

(Collision shape is convex hull).
Substeps:

Collision shape is set to sphere. Increasing steps/s causes no difference. Result:

The spheres go less deep through each other, but the problem is still there. If anyone has a suggestion...?
The bounciness of the spheres during animation are quite high, although these are Rigid Bodies. During animation:

Give us your rigid body settings - what collision shape you use, and your solver settings (how many steps/s and iterations does it use).

Related The choice of the BU size is arbitrary, and can be converted to a length unit using the scene unit scale settings.  Using such small sizes could I believe, lead to precision errors. If the height of the slice above is 0.02  then your smallest droplets are 0.001 or less. Have you tried using a bigger size? maybe 2 bu for the slice, and droplet sizes scaled accordingly.

I've already tried bigger sizes. But also without cross-section it is already visible that the spheres go through each other.

Where  can I find the solver settings? (which tab/panel?)

@Jan I guess Jerry means the Rigid Body World which is Found in Properties Panel > Scene

You definitely need to use Sphere as the collision shape, it is the most accurate (for spheres). Yes the rigid body world settings, you can increase the steps to increase accuracy.


text:
Is it possible to make Particles follow Displacement Node?
I'm faced a problem that I can't find a workaround for.
Displacement Node and particles.
I understand that in modifiers section of an object the particle effects have to be the last ones to make them follow the modifications, but what about Displacement Node?
I'm using multiple nodes on my setup to modify the actual displacement, so it's not possible for me to use the Displacement Modifier instead of Displacement Node.
It would be great to make Particles just follow Adaptive subdivision + true displacement but I can live with normal subivision and displacement node (I duplicate the object and use one as emitter, with normal subdivision, and second use microdisplacement).
Any workarounds to make it work?
.blend as example:
mirror
My mirror of this .blend:
mirror2
Problem visualisation:

/edit:
Have to edit because someone marked is as duplicate:

No, person you mentioned in link uses Displacement Modifier. There's
  no problem with Displacement Modifier and Particles. There's problem
  with Displacement NODE (material node), which is still in development,
  and I'm looking for a workaround.

I think I had the same issue: https://blender.stackexchange.com/questions/95183/make-particles-follow-true-material-displacement If that is the case what i did was normalize the displacement node and baked it, then used it as a texture in modifier stack

@JohanApes Can you write a guide? I'll check if that works for me.

@JohanApes I've tried baking displacement in 2.8 cycles, but the whole image is gray. Guess displacement baking does not support Displacement Node displacement. :/

Displacement Node is calculated at render time, it can't be used elsewhere outside Cycles render as far as I know

This is a method that i used with true displacement in experimetnal 2.79
1)Use the node wrangler addon to preview the output of the displacement node
2)the values will most likeley be clamped, so you will have to normalize them in order to see the [0-1] range. Use greater then and less then operations to find what are the maximum and minumum values
3)Use add and divide operations using the values you got in 2) to get normalized map
4)Bake the height map (I used diffuse shader and baked colour)
5)Plug the baked height map into the displacement modifier

Thank you.
I've tried it but the Displace Modifier uses different logic than Displacement Node. Displacement Node 'Scale' is not the same as Displace Modifier 'Strength'.
I've spent about 12 hours already experimenting with that. I've used Emission node and baked emission. The baked map is good, I can use it in the Displacement Node as input instead of the original nodes, but using it in the Displace Modifier gives me different results (using UV mapping) - due to differences in Scale and Strength. :/


text:
Cycles: Glass not rendering as transparent in CPU mode
AMD Ryzen 7 2700 8-core 4.1, 32 GB RAM, RTX 2060 (6GB VRAM)
I have a glass and transparent BSDF set up correctly in Blender, and the texture set to alpha clip, and alpha hashed for shadows. The glass works perfectly in GPU mode but is not showing the image behind it in CPU mode - simply switching from one to the other.
The scene, even with optimisations, is still too large to render on the GPU for my card. Simply switching from GPU to CPU to allow for rendering the image results in the glass/transparnet shader no longer being see-through.
Is this a bug or is there something I have missed?

Could you share your material setup?

Yes I could but it's simply a glass shader, and a transparent shader mixed going into the surface. Neither the glass or the Transparent on their own work in CPU mode. They are fine in GPU mode. Why would that be?

How do you mix them? What is the difference between the image on the left and the image on the right? If the scene is too large, how do you know it looks fine on the GPU? Would be easier if you’d share the file or give us a little more information.

Scene on the left has the image passing through the glass (GPU mode) and the scene on the right does not. They are being mixed simply with a mix shader. It does not matter whether they are mixed or not. Neither the glass shader or the transparent shader work in CPU mode. The issue is not the shaders, it is that CPU mode is not working for rendering a texture transparent.

WRT the image passing through the glass - the image is an "image as plane" of clouds. I am trying to transition to cycles from Eevee and experimenting with work flows. The model is of a steampunk airship cabin and you are looking at the circular observation window. The ONLY difference between the scene on the left and right is whether it was rendered in CPU mode or GPU.

If you could at least add a screenshot of the node setup & material settings, that could go a long way here.  No one can answer this question based on just the CPU/GPU tidbit of info, that's not nearly enough detail to figure out what's going wrong here.

Ok, I will do this, but as I explained in my post...simply a glass shader OR a transparent shader connected directly to the surface, with NO other shaders or anything gives the same result. It's the first thing I tried. Simply a glass shader, or a transparent shader works in GPU mode but NOT in CPU mode.
There are no other materials involved.

I have added a node set up to the post. Note: I tried with the material output setting to "all", and I took this screengrab while experimenting setting it to cycles. It made no difference. Also it makes no difference whether I use CUDA or Optix - both work, but CPU only does not.

Could you share your Blender file?

Not really...it is a commercial model and the file size is over 1 Gb. What I will do today is do some tests in a blend file with just basic shapes and textures. If it doesn't work there I will share that as well.

After doing some tests, I have been able to create a simple scene with glass and transparent shaders working with CPU. Note; viewport de-noising crashes Blender instantly in CPU mode. I still don't have any idea as to why the scene I am playing with will not render transparent surfaces in CPU mode.

@DrIgnatiusCole, at least you could post a blend just with the glass object and its material! But just for confirmation: Does this glass has some volume (front and back faces) or is it just a single surface? the last don't work well with the glass shader, since the engine assumes everything before or after the surface (depending in the normals) to be inside glass.

That's a good idea...I'll do that. That's a step I should have taken trouble-shooting anyway. To answer your question, YES, I added some thickness with the default setting of the solidify modifier. It still doesn't explain why in both GPU modes, Optix and Cuda, the surface works as expected, but in CPU mode it does not. I'll post a blend file with just the elements affected later today. Good idea.

Your setup works for me under CPU ... Preview Does this blend file works for you? If it doesn't work for you, it can be graphics card.

Hi vklidu, thanks for this. I actually set up a simple test file and switching between CPU and GPU worked fine for me as well. So it must be something in the file I was working with. I will try to get extract the relevant bits and post later today.

This may or may not help your problem but you shouldn't use glass and transparent shader mix, instead, for realistic results, use Principled BSDF with transmission of 1, if you're using eevee, you will need to enable screen space reflections and refraction in render settings, check refraction checkbox in material settings and set refraction depth to something other than 0.

Hi and thanks for the comment. Using glass and transparent shader together works fine in cycles (and Eevee) and allows to control the density of the texture of the glass shader. In this case I have a glass scratches texture which on it's own would be too strong. If I use a glass shader I can control the refraction angle.
The issue here really is that everything works fine in GPU mode but not CPU. This was true whether I used transparent or glass shader on their own. I will try to post the elements later today and see if anyone can replicate.


text:
Boolean operation can't be seen in Viewport Shading
I have created an object with screw modifier and I try to use it with boolean modifier to cut through a cylinder, but it's not visible in Viewport shading. It is visible only in x-ray mode. It works with a cube and sphere. Where do you thing could be the problem?
EDIT:
There is only one cylinder as you can see here:

you have to remove the external cyclinder

There is only one cylinder there, I edited my post with screenshot for proof.

I follow you instructions and my result is ok (https://blend-exchange.giantcowfilms.com/b/X8W8ZoLo). Can you upload your file to check it?
https://blend-exchange.giantcowfilms.com/

I see yours is as it should, but this is mine -

Hm, that's wired. For some reason the faces that end up inside the screw modified circle object are not deleted. As far as I can tell, the rest of the geometry is there and in order. (If no other solution is found or satisfactory, the faces could be deleted manually.)

Try adding some thickness to the cylinder

It didn't worked with thickness. Even filling the circle don't work.

I would check the face orientation of both objects. The option can be found under Viewport Overlays. If either of your models is red instead of blue, then your issue might be caused by the faces being flipped.
To fix that, go into Edit Mode and under Mesh > Normals, use the Flip button on whichever model is red.
I just saw you uploaded your blend file. You had a couple of issues happening with this project.

The normals on the screw we're in fact flipped. To fix this you just had to select Flip under the modifier settings for Normals.

Your screw wasn't "watertight". You had to add end caps to each end so it so there are no holes in it. To do this I had to apply the modifier then fill the ends in Edit Mode.

Lastly, you needed to set the Boolean modifier to Exact instead of Fast on the cylinder.

After that it came out fine.


text:
Floating Mosaic
Hope someone can help here.
I'm trying to create a mosaic using an .SVG file and then animate it with a wave effect so that it looks like tiles floating on water with the shape of the SVG.
The only thing that came to mind was to convert the SVG file from curves to mesh, subdivide it and then turn on instancing by vertices using a brick model so that every vert of the svg would have a brick in it's place. It worked to some extent but it is really messy.
Do have any other workflow to suggest in order to achieve this effect?
Here is an example of what I mean:

Thanks a bunch!!
Kris

Hi and welcome. Could you illustrate what you want? Some sample image or drawing? (because from what you say so far... several possible things can come in mind).

Hi no sorry I don't have a specific drawing. Let's say the thing I need to know is how to fill an SVG image with bricks. Do you think that would be possible?

I'm curious if there is a reason you are doing this with the svg as objects and not using an image map and alpha on a subdivided plane and cloth or displacement or something along those lines... basically a flag thats parallel to the ground.


text:
Different Z Pass values given by Eevee and Cycles
Problem
I've been reconstructing point clouds from blender's Z-pass outputs; saving to .exr to capture the full detail. I've noticed that when I use the EEVEE engine flat surfaces are reconstructed flat - but using cycles the same captured Z pass includes radial distortion even when accounting for the camera intrinsics.
Linked Images
Cycles Z pass to point cloud Eevee Z pass to point cloud
At this point I'd be assuming that Eevee is taking Z distance from the camera, whereas Cycles is calculating the length of the path before intersection, but I can't find any confirmation of these different behaviours.

Upon further searching, this post https://blender.stackexchange.com/questions/130970/cycles-generates-distorted-depth suggests that this is the result of the pinhole camera model used by the cycles renderer. As is pointed out; it's confusing that the two rendering methods have a different camera model; and this has persisted with the Introduction of Eevee

This question may be duplicate of the previous, although the rendering engines being compared are different, the behaviour is the same.


text:
How Do I Create a Gem Shader by Mixing Shaders Together?
I'm trying to make a procedural gem shader that Is scientifically correct and physically correct. If I mixed beryl, beryllium, aluminium, chromium, vanadium, and iron shaders using an add shader it turns pure white
If I use A  mix shader it turns into metal and isn't transparent like A Gem.
If I get rid of some of the metal shaders like beryllium, aluminium, chromium, vanadium, and iron while using a mix shader then it isn't pure white.
How can I Mix all of the shaders and keep it from turning pure white?

I gather you want to compose an "uber shader" for gemstones that contains all of the elements a gemstone might be made of, but I suggest that this is not the best way to go about it.  You are talking about shaders with metallic components that will govern the surface response of the mesh, but for a truly scientifically and physically correct gem you would need to account for volumetric effects as well, no?  Such a shader may be hard to find.

One point to note regarding the Add shader is that any time you add color values, you will eventually get to pure white when your R,G, and B values reach or exceed 1. It's literally adding the RGB values.

I would also say that if you care about accuracy you should probably create separate shaders per mineral. It's like when people want to create a "wood" shader, but the internal structure of wood is what creates the distinct look of each species. Trying to support all the possible variations would be really difficult, and you'll be able to generate a lot of wildly inaccurate species (or in this case gems). If you're going for artistry then who cares, but if that is the case then why even bother with the tons of effort towards realism?

The problem is that what you are doing isn't how metals behave when they're in a crystal lattice, so it's not physically correct.  Also, shaders don't really model physics, but rather try to mimic surface behavior.
What you need is a source of the correct color for the mineral that you're trying to model, in its crystal format.  Crystal, because gem stones are usually the crystal versions of minerals.
Since you started your list with beryl, I suspect you're looking to reproduce an emerald gem, although it can be the base of a wide range of crystal forms
I'll use an emerald shader as an example, but the shader only needs a few small changes to model the other forms.
There are many ways to do this, but this one is simple to explain:
Most of the color in a gemstone comes from the interior of the stone absorbing light  in certain bands.  Otherwise, a good way to model a gemstone is with a glass shader, one of the few times that glass is a good choice.
Because the material output node has support for both a shader and a volume shader, that's what we'll use:

The glass shader should be set to white, no matter the color of the gem.
The glass shader's IOR value might have to change to match the IOR of the gem.
The actual color of the gem comes from the absorption shader.  In this case, I've set it green to match emerald; but as I said, beryl is the basis for minerals of many colors.  Just change the color to match the mineral gemstone you're trying to model.
EDIT:  from the comments, I was reminded that if you are going to use the Material Output's Volume input in Cycles, you need to go to Properties Editor, Render Properties tab and under Light Paths -> Max Bounces, change the setting of Volume from the default of 0 to some larger value.

Here is a diamond with the emerald shader
Volume bounces set to 0

Volume bounces set to 5

Relevant: https://blender.stackexchange.com/a/237777/110840

excellent point.  I'll edit the answer to mention that.

I think Marty's first point is that, for example, ruby is aluminum oxide with chromium impurities giving the reddish color. However, you cannot mix an aluminum oxide shader with a chromium shader and expect to get ruby. Cycles isn't physically correct like that, and a simple "mix" shader wouldn't behave the same as impurities in a crystal lattice.


text:
I need to find out how to add an UV map to a newly made face via a script
This code creates a simple mesh (with two polygons instead of just
one), but I am unable to find out how to give each vertex in the
mesh a proper and precise place within the UV map. The idea is to
create a quad polygon, give it a place within the UV map. Then when
all the polygon faces are completed all vertices(within the exact
same coordinates) get merged into one single mesh
Any ideas?
Thanx in advance! sorry if the question is too simple
for this forum ...
## create mesh
import bpy

## CREATE MESH
verts = []
edges = []
faces = []

verts.append([
    0.0, # x
    10.0, # y
    0.0, # z
    ])

verts.append([
    10.0, # x
    0.0, # y
    0.0, # z
    ])

verts.append([
    0.0, # x
    0.0, # y
    10.0, # z
    ])

verts.append([
    -10.0, # x
    0.0, # y
    0.0, # z
    ])

edges.append([0,1])
edges.append([1,2])
edges.append([0,2])
edges.append([2,3])

faces.append([0,1,2])
faces.append([2,0,3])

##########
name = "New Object"
mesh = bpy.data.meshes.new(name)
obj = bpy.data.objects.new(name, mesh)
col = bpy.data.collections.get("Collection")
col.objects.link(obj)
bpy.context.view_layer.objects.active = obj
mesh.from_pydata(verts, edges, faces)

Just a small, friendly tip on code style: we all know the order of coordinates, no need for the # x, # y, # z comments. Also for simple values I would write them in one line. Then you can also instantiate entire verts list in one go, using space padding for readability. Also, using bmesh you don't need to specify edges - examples

You don't need edges for from_pydata either (just pass [] for the edge list).

Thx for all the tips!

You need one UV coordinate for every corner of a polygon. Fill in an array with your UVs with something like:
uvs = []

# Face 0
faces.append([0,1,2])
uvs += [
    0.0, 0.0,   # UV for first corner (vertex 0)
    1.0, 0.0,   # UV for second corner (vertex 1)
    1.0, 1.0,   # UV for third corner (vertex 2)
]

# Face 1
faces.append([2, 0, 3])
uvs += [
    0.0, 0.0,   # UV for first corner (vertex 2)
    1.0, 0.0,   # UV for second corner (vertex 0)
    1.0, 1.0,   # UV for third corner (vertex 3)
]

Then after from_pydata create the UVMap like this:
# Create a new UVMap
uv_layer = mesh.uv_layers.new(name="UVMap")

# Fill in your UVs
uv_layer.data.foreach_set("uv", uvs)

uv_layer.data.foreach_set("uv", uvs)
It fails at the very last instruction, The array is only half of what it is supposed to be, so no UV map is created and I get an error; "Error: Array length mismatch (expected 24, got 12)"
I have no idea why there is an array to match double the amount of vertices of what was given ... ?

@Comic_Interlude I've tested this answer and it worked for me, I imagine Scurest also tested it. Perhaps you've modified your script incorrectly, for example perhaps you just pasted this answer's code to your script, and so you ended with twice as many faces?

Okay, this code works perfectly, but I made the (very stupid) mistake not to check "edit mode" on, so the freshly made uv isn't visible then! which left me miffed for some time.


text:
where this background come from
I have download one model from web, when in texture view, there shows a background which seems in a factory house. but I have turned all objects off, see attached picture.
if in render view, no such background.
what is this? how can I find it out? how can I change/replace it etc?

The background is an HDR that is in the world lighting settings.  If you open the shader editor and go to world mode you'll see something like this:

perhaps without some of the nodes.  The block with the orange header is an Image Texture.  It is the source of the garage image in your case.


text:
Does my mesh have a good poly count for a game?
I'm a beginner 3d designer and I'm making a model, but I want to know if my model has a good poly count for a game. (Image included) If anyone can help thanks.

Also, if it isn't good what can I do?

Hello and welcome. This site works best for focused questions and answers and is not
meant for opinions or open ended discussions. You can use the forums
at https://blenderartists.org/, there are sections for focused
critique and work in progress. To understand how to make better use of
this site please take the [tour] and read through the [help] center
section, particularly How do I ask a good question?
and [What types of questions should I avoid asking?]https://blender.stackexchange.com/help/dont-ask)

Flagged as opinion based. Here's an opinion: for spheres and cylinders it has way too many triangles, especially for a video game. But I could imagine scenarios that would justify the amount...

See https://polycount.com/discussion/141061/polycounts-in-next-gen-games-thread for recent-ish stuff in AAA titles (which will be more optimized than most indy things.)  The short answer: no, your meshes have way too many polygons for what they are for use in a game.  By at least sixteen-fold.  The long answer: This is the wrong thing to measure.  You need to know scene poly counts; you need to know armature deformed poly counts per scene.  Talk to your coder to make a test to see what you can afford in your engine.  If you are the coder, make your own test.

This kind of question is usually closed as "opinion based" because a yes or no answer is a matter of opinion, but it's a good opportunity to describe what "too many polygons" means and that's something new modelers can benefit from.
Your question can't be answered in a vacuum.  To know how many polygons a model can be allowed, we need to know what it is going to be used for.  Crudely put, there are three classes of game assets, and the first two both require low polygon counts.  The third class might allow a high polygon count, but even that depends.
The first kind of asset is not important.  It might be a building in the distance, or a rock close up that's among a pile of rocks.  Such assets should be low polygon assets, because they're simply not going to get notices.
The second kind of asset is more important, but should still have a low polygon count.  These are props that might be noticed, like a sword on a rack, but that aren't going to be seen very close up or in great detail.
The final kind of asset is often called a hero asset.  It might be the main character, or the object of the quest.  It will receive a lot of attention in the came, be seen close up, and its detail will be important.
But that leaves us with the question of what are 'low' and 'high' polygon counts.  That too depends and can't be answered in a vacuum.
First, there's how powerful the machine's graphics are that the game will run on.  A low polygon count on a high end game console might well be a high polygon count on a smartphone.
Second, there's the overall artistic style of the game.  A game that's meant to be nearly photorealistic will demand a much higher polygon count of each asset than a game that's deliberately styled for a low-polygon world.
So, as you can see, there's no one-size-fits-all answer, but there is a good rule that many asset developers follow:
An asset should have as many polygons as is necessary for it to fit the artistic style of the game its meant for and the role it has in that game but no more than that.
That said, there's another aspect, and it applies to your model in particular: sometimes you can get the appearance you want by using fewer polygons but other techniques to create the impression of detail.
In your case, you have spheres and hemispheres that have far higher polygon counts than needed to give the impression of a smooth round object, even in a hero asset.  Reduce the polygon count and rely on shading techniques to give you the smoothness.
Also related, is the need to fake detail by using shaders, doing things like creating bump maps that give the appearance of detail but without the high polygon count.


text:
Tait Bryan Rotation with Fixed Camera
I basically need to rotate a person's head with a fixed camera view, in which Tait Bryan Rotation (sometimes, Roll/Pitch/Yaw,) is applied.
However, there seems to be no python scripts for automating that process...
Any recommendations or advices in doing this?
Thank you!!!

I don't know of any existing script to do this, but Tait-Byran rotation can be composed as three consecutive Euler rotations, X, followed by Y, followed by Z, so it should be straightforward to write such code.

Thank you! Do you have any script I could take reference to understand how to make video/screenshots of an object for every rotation..?


text:
Beginner : How to Colorize depending on displacement height?
I am starting to experiment with blender nodes and displacement, my goal was to create a texture where the high displaced areas are white and the low displaced areas are black.
I generated a Musgrave texture and used the output as both surface and displacement, however, some top areas appears black and some lower areas appears white, what am I missing?

I think that it's that you're using different normals for displacement as for the Musgrave texture.  Run the output of the Texture Coordinates Object to the displacement input.

I can't tell exactly why your nodes don't work but there are a few issues. Unfortunately, Blender's documentation is very vague sometimes.
First, it seems that the Object Coordinates are not the right choice for the Musgrave Texture. The documentation doesn't tell what this is exactly. But it's better to use the Generated ouput here.
Second, the Height of the Musgrave Texture ranges from -1 to 1 and not from 0 to 1. Because you set the Midlevel of the Displacement to 0.5 everything is a bit off as a result.
Don't worry, I also wasn't aware of this and the documentation is here very vague again:

Musgrave - Height
    Texture value.

Ah yes, now it's clear! ;-)
Ok, the range is then revealed in the example below in the documentation and it shows how to map it properly into the range of 0 to 1 with a Map Range node.
Knowing this, we now can fix the material:


text:
I can't render with GPU no matter what project I'm on
Firstly, sorry for my english and I'm a very beginner in blender.
I made something in blender, changed to Cycles and tried to render in viewport. Normally, it would take something like 30 seconds to render but it stuck on "Path Tracing Sample : 1/32". It isn't a big project. On other projects it is fast but on the project that I just created, it is very very slow. I decided to use my GPU for faster rendering but when I go in rendered preview it says : "Cancel" When I render, it shows "CUDA error at cuCtxCreate: Launch exceeded timeout". It happens quick, like in seconds it rendering nothing and showing that error on top. I tried render other projects with GPU and it giving same error.
Can someone help me?
Edit : I fixed the extremely slow render time by deleting the carpet on my project :)

Going to ask: What video card are you running?

GTX 1050 Ti with gaming drivers.


text:
Bone rigging incorrectly
I am making a rigged character. When the wrist is lifted up, the whole arm should move, and the torso should not. The correct 'connecting line' from the wrist to the collarbone (may be hard to see, click on the image and it is clearer):

however the opposite arm's wrist is connected to the pelvis so that when it is raised the whole character tips:

How do I fix this, and connect the left wrist to the left collarbone, like the right?
Thanks in advance.
here is my .blend file:

EDIT: It turns out you have the Auto IK option enabled. To turn that off, press N with your mouse in the 3d view to open up the sidebar and go to the tools tab.

Uncheck that and you are good to go!
EDIT: The information below did not answer the question directly, but may help others as it can cause a very similar issue.
I looks like you just need to adjust the Chain Length in the IK constraint, found here:

What this does is tell Blender how many bones in the chain to use. The default is 0, meaning the whole chain is used, in your case up to the pelvis. I think you would need to set yours to 3, but you'll be able to see the line update as you change the length.

I don't think I am using IK on my hands, only the legs. Should I create this constraint for both shoulders?

When a bone is yellow with a dashed line connecting to another bone that means there is an IK constraint. If there wasn't, you wouldn't see any movement in the rig when you move the wrist, the wrist would just rotate. If you select the wrist bone (the yellow one in the second image) you should see an IK constraint in the bone constraints tab (see the image in my answer above). This is the right way to do it, and you wouldn't need to anything to the shoulders. The IK constraint is applied to the bone that you want to use to control the other bones in the arm or leg.

Sorry, thanks for all your help so far. Yes, it would seem as though there is an IK constraint on the wrist, I can't seem to see it in the inspector. See here: https://imgur.com/a/X01pDkR . I'm still quite new to Blender so I apologise I am am a bit slow

Perhaps there are doubles of some bones. Try selecting the wrist bone and hiding it with H. Since there are flashes of yellow/orange on certain bones there must be something there. If you don't mind sharing your file, you can also upload it and link to it in your question using this site: https://blend-exchange.giantcowfilms.com/

Absolutely! I have stuck it in the question. It doesn't seem like there are any duplicate bones from my h press, though I am probably doing it wrong. If all else fails, could I just delete the badly behaving side and mirror it? Though I don't know how this would fix the head...

I found the issue, and updated the question with the solution.

I would never have figured that out. You are amazing :) Keep on, dude