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.
Select the .vdb volume in the File path attribute.
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.