§36's collisions option. "none" is the default (or the existing
collisionPlaneY bounce when that field is set). "depth-buffer" kills
particles that fall below a ground y on the CPU; on a GPU emitter the
device kernel rests them on that plane (a documented stub — true
depth-texture collide-and-kill needs a bound scene depth and is staged).
§36's
collisionsoption."none"is the default (or the existingcollisionPlaneYbounce when that field is set)."depth-buffer"kills particles that fall below a groundyon the CPU; on a GPU emitter the device kernel rests them on that plane (a documented stub — true depth-texture collide-and-kill needs a bound scene depth and is staged).