question

Huang Yaofeng avatar image
Huang Yaofeng asked ·

aiVolume (Step Size?) render artefact with aiStandard Volume in Maya

I use ai Volume to render a smoke of Houdini with VDB, but it appears artefact

I change step size of AiVolume, and the artefact change, so I assume that's the problem, but even I use 0.001 step size, I can still see the artefact, how can I fix this?...

Thanks in advance

StepSize 0.1

StepSize 100

Update:

In the scene there are two AiVolume, but we can't see the other AiVolume through camera.

I really don't think the quality is the problem, it looks like this when I render without the other AiVolume, (the black part inside the smoke is the shadow of environment)

With Environment

Without Environment

So maybe there is some parameters I have to set to avoid the artefect influenced by the shadow of the other AiVolume?

rendervdb
artefact-stepsize01.jpg (20.6 KiB)
artefact-stepsize100.jpg (31.1 KiB)
withenviro.jpg (22.6 KiB)
withoutenviro.jpg (22.1 KiB)
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Girijashankar Senapati avatar image
Girijashankar Senapati answered ·

Can u try increasing the volume resolution(quality) and them export from houdini? That might help.

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Huang Yaofeng avatar image Huang Yaofeng ·

The reason is shadow of another VDB's Volume, after I deleted it, artefact disappears, even with lower quality of VDB...

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Lee Griggs avatar image
Lee Griggs answered ·

Are you using Volume Displacement? Do you have any other shaders connected to the Standard Volume?

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Huang Yaofeng avatar image Huang Yaofeng ·

No, I just use Standard Volume, displacement is 0,0,0; no Volume Dispacement involved

The reason is shadow of another VDB's Volume, maybe I miss some parameter to set in Lighting or Render Setting?

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Lee Griggs avatar image Lee Griggs Huang Yaofeng ·

I have this issue from time to time (especially when using displacement). Maybe try Girijashankars advice.

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