pushmove objects do not obey gravity, and do not interact with each other or trigger fields, but block normal movement and push normal objects when they move.
onground is set for toss objects when they come to a complete rest. it is set for steping or walking objects
doors, plats, etc are SOLID_BSP, and MOVETYPE_PUSH
bonus items are SOLID_TRIGGER touch, and MOVETYPE_TOSS
corpses are SOLID_NOT and MOVETYPE_TOSS
crates are SOLID_BBOX and MOVETYPE_TOSS
walking monsters are SOLID_SLIDEBOX and MOVETYPE_STEP
flying/floating monsters are SOLID_SLIDEBOX and MOVETYPE_FLY