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Stefano Feltre avatar image
Stefano Feltre asked

PolyMesh To Volume Lee Griggs' Tutorial

Hei Everyone,

I've been trying to follow the tutorials of Lee Grigg's PolyMesh To Volume:
https://docs.arnoldrenderer.com/display/A5ARNTUT/Polymesh+to+Volume

However, I am encountering some problems and I hope some of you could help me with this...

-Whenever i convert my polymesh to volume and I render it, this becomes really noisy and greysh(even though I set the color material to full white), while Lee's one is completely white and doesn't show any noise whatsoever..


-The main problem is, whenever I assign the displacement to the model and I render it, I encounter the problem shown in the image below(The mesh is open on the mouth , but before applying the displacement it renders just fine, I even tried with it's dynamesh version[closed] and still it gives me the same problems, black spots, but just in different areas,I even tried with a really lowpoly mesh, the problem remains...)

render.png

scene.png

grapheditor.png

-The step just after applying the displacement is the one to apply a texture to the displacement, I tried applying a Noise Shader, but it covers the entire model, while Lee's one affects just the back of the head, how is that possible? Does anyone know what texture he used exactly? Even because he's effect looks really nice with it...

I also attached my Maya scene. Hopefully someone could have a look and help me out.

-The open mesh is the visible one once you'll open the file, if you want to give it a try with the closed one in the outliner is called "Dynamesh_geo"

-There are some shaders in the scene, the one you want to use(which is already applied to the mesh anyway) is the one called "PolyMeshToVolume01"

Link To the Scene: https://we.tl/t-MpDz7zOiEC

arnoldproceduralsvolumetricstutorial
render.png (306.3 KiB)
scene.png (66.2 KiB)
grapheditor.png (48.3 KiB)
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Stefano Feltre avatar image
Stefano Feltre answered
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Lee Griggs avatar image
Lee Griggs answered

To reduce noise in volumes you must increase the lights volume samples.

Are you using displacement or volume displacement?

>while Lee's one affects just the back of the head, how is that possible?

I use a ramp to determine where the displacement occurs.

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Stefano Feltre avatar image
Stefano Feltre answered

I'm using 6 light samples for each light and I set he resolution of the light to 3000

I never used Arnold before but if you take a look at my image at the end of the message "grapheditor" it shows that I connect the displacement to the node, doesnt that mean I'm using the "normal" displacement already?

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Lee Griggs avatar image
Lee Griggs answered

That link is to the tutorial template. Try this link.

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Lee Griggs answered

Not light samples, volume samples in the light.

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Stefano Feltre avatar image
Stefano Feltre answered

I took a look at the link to the tutorial template. I'm getting there, but not quite yet...

1)I increased the volume sampling of the light I have to 10, it' s still not white

2)Whenever I applied the displacement to the volume shader this is clearly visible on the head mesh, but on the vdb is like it's not there...I therefore increased the Output Max value to 50 just to see if it is affecting it in any way or not, and the result is reaaaaally weird, I don't get why I'm getting those squares, while the other half is not being affected at all(without displacement it renders just fine)

3)I don't get through which parameters you connect the range to the ramp and the ramp to the second projection...

pp.png


pp.png (330.6 KiB)
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Lee Griggs avatar image
Lee Griggs answered

1. Can you post renders and screengrabs of your settings and a simplified scene?

2. I don't know why it's not on the VDB. Yes, those squares are normal. You will just have to play around with the Range values and texture.

3. Its indicated in the screengrab at the bottom of the tutorial and its included in the scene file there.

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Stefano Feltre avatar image
Stefano Feltre answered

Hey @Lee Griggs

1)graph.png
Scene:https://we.tl/t-TySe0QCIdI
3)Mmh I might have been looking at a different tutorial but in the one I'm looking at there are no screenshots of any hypershade nodes at the bottom of the page...At most it's between the "tools" menu an image showing the graph, but this just shows that the 2 nodes are connected, but not which attributes are used for the connection...The scene that you attacched on the messagge above (Because there are no scene included in the tutorial) contains just a noise node connected to a standard volume shader, so not exactly what I need.
Thank you.


graph.png (46.1 KiB)
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Lee Griggs avatar image
Lee Griggs answered

The tutorial with screengrab and scene file is here.

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Stefano Feltre avatar image
Stefano Feltre answered

@Lee Griggs
I might be missing something, but that's the scene I was talking about, the graph node is really simple and contains just a noise node and a standard surface node...So it doesn't really explain what I need...

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