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VDB scaled up?


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Hello! I'm doing some R&D and am hoping to convert my polygon mesh to a vdb to be referenced elsewhere in my project. When I preview the vdb, however, it is scaled much larger than I expected and I'm not really sure what to make of it. Any help would be appreciated! I've attached screenshots, the first is the geometry, and the second is the resulting voxels.



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Decrease the voxel size on your VDB from Poly node. The closer you get to 0, the more accurate it will be to your original geo.

So start with 0.05, and then lower slightly from there if it's not enough. So a decrease in value causes an increase in resolution on your VDB. :)

Edit: just fought off the sleep that's currently trying to overpower me, don't think I answered your question...

Edited by sandford
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Thank you for the reply! My apologies if I wasn't very clear. The problem isn't the level of detail in the voxels, but the overall scale. In the second screenshot, the light grey plane is the geometry I'm trying to get voxel information from. As you can see, the resulting voxels are overall scaled way up compared to my original geo.

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That is odd, any chance you could post the hip file? or maybe a screengrab of your whole network? :)

EDIT: I just noticed you're using your custom wave deformer, pretty cool.
Just throwing these out:
- Are there any custom attributes generated by the deformer?
- Could you try adding a Convert to polygon before applying VDBfromPolygons?
- Could you try maybe creating a new Geometry node, then Object Merge your wave before doing VDBfromPolygons?

Edited by galagast
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Are you perhaps object merging it into another geometry object in your custom deformer?
Are you doing any transformation/scaling in the subnet? If so, you will need to compensate by either inverting the transform or simply scaling it back down before VDB-ing.

Or, does the parent object have any scaling at the object level? This can cause issues down the line, and if you do, try moving the transforms/scaling to SOP level, cleaning the object transforms, and see if that makes a difference.

Hope this helps!

Edited by Matt_K
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  • 2 weeks later...

Apologies for the late reply!

I do think the scale of the object is being affected by my deformer, I didn't realize how this would affect VDBs down the line. Thank you for the insight! I've got some ideas for work-arounds for it now.

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