In this tutorial, we will go through how to setup and use the Volume Sample Float shader to adjust the color temperature effect of an OpenVDB file.

A tutorial on how to write volumes to OpenVDB from Houdini can be found here.

 

Standard Volume

Volume Sample Float

We can use a Volume Sample Float shader to control the appearance of the fire volume effect. This shader will remap the values of the 3D voxel grid in the same manner as tone-mapping and remapping filters to an image in Photoshop, which operates in a 2D grid.

 

We can use the Volume Sample Float shader to alter the appearance of the smoke and fire. The following images show different adjustment attributes and their effect on the volume.

Input Max

Bias

Gain

Output Max