add voxel padding to vdb, what's the equivalent of volumeresize for vdb?

[karen]

When I work on vdbs starting from a geometry, e.g. a box, I get sharp edges on the vdb (representing the boundaries of the box).

If I work with volumes, I can add a volume resize, give it some voxel padding (room to breath) and the sharp boundaries are gone.

But I want to work with the efficient vdbs. How do I add voxel padding to a vdb?

if I try in the vdbfrom polygon using the exterior band voxel, nothing happens the box boundaries remain unchanged, no more space is given to the vdb:

 

Edited May 27, 2020 by karen

[flcc]

Exterior Band voxel is relative to SDF (Distance VDB), not Fog.
Band voxels isn't for volume resizing.

May be you should take a look at some tutorials that explains how VDB work.

[karen]

thank you, VDB only takes keeps voxels that have a density threshold higher than a default (very small value), and deletes the rest. That I know. But I started from a box, so no matter how clever the vdb is, the box is limiting it (used polygon box then created vdbfrompolygon). That's what I want to avoid since I'm applying a noise that goes beyond the box but gets clipped by the box boundaries.

The question is how to give the vdb more room so the noise can express itself with freedom and not get oppressed by the boundaries of the box?

[flcc]

This is one way to resize a vdb with bounds and combine_vdb.

Resize_vdb.hip

[Skybar]

VDB Activate -> Expand

[flcc]

Way more simple