tips mainly for Houdini


Add "Cd" volume (3 floats).
"vdb from polygon" can make density and Cd at the same time from mesh.
Multiply density to Cd.
We need to make value of Cd 0 at outside mesh.
Feed Cd to simulation
  • Add "source volume" to import Cd. (Or just manually import field, if you prefer)
  • Add "vector field" to make Cd.
  • Add "gas advect field" to advect Cd field.
  • Add "gas diffuse" to mix values nicely.

(Don't forget resize Cd field if fields are resized.)


In case "vdb from polygon" is used to get volumes from attributes, we should convert float attributes to vdbs first. Then convert vector attributes.