Emitter : Mask

This feature works similar to subtractive Boolean operations: it is possible to use objects to cut away parts of a fluid volume.

From Collision Objects

This option works automatically and detects all objects with a → "RFCollider" and intersects the particles volume:

• Particles inside these objects will be removed.
• The "Fill" emitter is a special case, because the fill object will not be considered.

Mask surface offset

With this value it is possible to inflate or shrink the object(s) virtually to remove more or less particles.