VDB Research

While I've been studying Houdini has evovled somewhat...it is a constant challenge with CG and tech in general to stay up to date. VDB's or 'openVDB' seems to have been born and matured and come into Houdini.

http://www.openvdb.org

online docs
http://www.openvdb.org/documentation/doxygen/

Technical Paper by Ken Museth
http://www.museth.org/Ken/Publications_files/Museth_TOG13.pdf


'VDB' is a open-source hierarchical data structure (and a suite of tools) developed by Dreamworks to handle high quality volumetric rendering (as seen in The Croods, Puss in Boots, How to Train your Dragon 2).

current version (Oct 2015) 3.1.0

Due to the data structure VDB enables constant time O(1) random access to voxels.

VDB allows almost realtime boolean operations

I tried this:
convert from polygons to VDB with "VDB from polygons SOP"
I merged a sphere with a torus, (VDB Combine) then converted back to polygon soup

this work flow allows us to boolean polygons in a new way to the old cookie SOP
which had its own inherent issues, but of course the accuracy of the result is dependent
on voxel resolution. Combining voxels has been previously (a while ago now )
described as a revolutionary way of modeling that was previously restricted by polygon limits.

You can merge different resolution VDB primitives together and the result can be either the lower resolution or the higher.

Houdini's cloud tools make use of VDB data structures.