This compound automates the process of creating an efficient MPM granular simulation setup. It computes the intersection of an animated object with a piece of terrain and builds three useful pieces of geometries which can be used for the MPM simulation:
(1) A 'source' geometry for sourcing the MPM particles only where the animated object intersects with the terrain geo,
(2) A 'container' geometry used as a collision object in the MPM sim, which holds the granular particles in place (lest they fall down due to gravity), and
(3) A 'carved_terrain' geometry which simply returns the terrain mesh, post-carving. It can be useful to scatter points around the granular sim, for rendering purposes.
Note that the terrain needs to be of planar topology, e.g. one-sided - not like box. The terrain and the animated object need to be supplied in the form of file-caches (Alembic .abc or .bob). A frame-range must also be specified so that the carver knows which frames to consider for the intersection between the animated object and the terrain. NOTE this compound was recently updated to work with Bifrost 18.104.22.168 or later.