Redshift Volume Material in Houdini

Download Houdini Project: Explosion HIP file

The video clip on the right is a preview for the “Redshift Volume Material in Houdini” tutorial.


Volumes in Houdini is a bit different compared to geometry. For polygons, you have points, vertices, primitives, and attributes. The attributes are used to store additional data values related to the respective points, vertices, or primitives and even details.

Volumes is quite different in this aspect, volumes are made up of voxels and store additional data values in a different type of format called volume primitives. But the term primitive in terms of volumes isn’t the same as the term primitive used in geometry.

Screenshot of density volume primitive driving the pyro smoke

Screenshot of density volume primitive driving the pyro smoke

Volume primitives refers to the type of data used to store the values for volumes. For example, a pyro sim will contain a lot of voxels but how can we illustrate how fast the pyro smoke is moving? It could be going very fast because of an explosion behavior that is being cooked. And what if you wanted to illustrate the speed of the pyro smoke by making the faster voxels red and the slower ones white? Visually distinguish the smoke by utilizing all the additional data that gets extracted from the simulation. Volume primitives can be used to drive the volume material in Redshift similar to the way attributes drive the renders for geometries.