Displacements on VDB ?

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You can't apply displacements to a VDB mesh, correct ?
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There's not really any such thing as a VDB mesh. It's either a VDB (A sparse Signed Density Field / Level Set), or you've converted a VDB into a polygon mesh (a polygon representation of the zero-level boundary)

Depending on what you need to do with it, you should either be able to apply a render-time displacement map to a mesh converted from a VDB as normal (although you'll have to work out a way to UV it first)

…or if you're looking to displace it for modelling/procedural purposes, you can effectively “displace” a VDB directly, by advecting it using a velocity VDB. That velocity volume could be anything, random 3D noise, etc. Use the “VDB Advect SDF” SOP. You could even resample the VDB resolution before doing that, to introduce more apparent detail to a surface.

Depends what you want to do with it at the end of the day.
Dan Wood
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Is there any where I can find on how to UV a VDB or displace a VDB as you mention using velocity VDB ?
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I don't know about tutorials as such. They're not exactly standardized approaches to anything, just ideas. It's more a case of just having a play around and referencing the Houdini docs. Maybe dig up some reference on working with VDBs in general to get more of an idea of the kind of approaches you can use with them.


UV the converted mesh just like you'd UV anything… either by hand, or probably more ideally by using the procedural UV tools in Houdini, then apply a regular displacement shader.


To advect a VDB, you can use a Volume VOP to fill a vector-VDB with, say, a 3D noise function, and then use that to drive the VDB Advect SDF node.
Dan Wood
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perhaps my comment from here will help you:
https://www.sidefx.com/forum/topic/45018/ [sidefx.com]
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Can you convert the VDB to a polygon mesh, sculpt displacements for example, then apply that to the VDB in Houdini ?
I'd love to see a tutorial on the VDB Analysis node.
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