Accumulate Mask With Solver

Accumulate mask values over time using a solver subnet in Houdini

Interactive Node Diagram

Accumulate Mask Using SolverSOP
Accumulate Mask Using Solver diagram
Null TERRAIN
Null WHEELS
maskfromgeometry1
solver1 (Subnet)
Null TERRAIN
Terrain geometry used for intersection.
Null WHEELS
Wheels geometry used for intersection.
maskfromgeometry1
Mask from geometry: wheels intersecting with terrain.
Group is created here by the mask attribute.
solver1 (Subnet)Dive
Solver subnet: Accumulates mask values over time.
Click to dive inside.

Purpose: Ensures mask values persist as wheels move over terrain.
Result: Outputs a mask trail that accumulates and does not disappear.

Transform node pushes down p.y of the group.

GLTF Preview

Preview the result: the mask trail accumulates and persists as the wheels move over the terrain.

Result Video

Result: This is the output with subdivided terrain geometry and refinement of the mask attribute.
The color is ramped by mask strength (black to white), showing the accumulation effect.

Group is created here by the mask attribute, and a transform node pushes down p.y of the group.