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Updated on Sept 27  2017


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copyright © Deborah R. Fowler

OpenVDB

Deborah R. Fowler



OpenVDB

Updated: Sept 16   2013 

What is a OpenVDB?  An open-source data structure and toolkit for high-resolution volumes. OpenVDB is now fully integrated into Houdini (12.5 and up).

OpenVDB is developed and maintained by DreamWorks Animation and is designed for manipulation of sparse volumetric data.

"OpenVDB is an open source C++ library comprising a novel hierarchical data structure and suite of tools for the efficient storage and manipulation of sparse volumetric data discretized on three-dimensional grids." Documentation for OpenVDB exists here. Also on their site are downloads - in particular the sample models could be very handy.

Here is an interview with Ken Museth and Jeff Wike of Dreamworks about OpenVDB.

Also, there is an excellent interview from fxGuide Aug 20, 2013 - Dreamworks Turbo using Openvdb and Houdini
At 23:05 is a diagram illustrating what an Openvdb data structure might look like.


In Houdini

Volumes allow you to store values for “voxels” in a space. You can store “metadata” (data about data), such as velocity fields (a velocity for each voxel), collision fields and so on.

Houdini supports two types of volume primitive at the geometry level. Standard Houdini volume is a box with a position, size, and orientation, subdivided into a 3D grid of voxels, a value stored at each voxel. An OpenVDB volume uses the OpenVDB library to represent a sparse volume very efficiently because it uses virtually no memory for “empty” voxels. (So it is really good for clouds and wispy smoke).

You can convert geometry to VDB volumes using VDB from polygons and VDB from particles nodes. Most things that work with standard volumes work with VDB volumes.