Check if entity hits ground/wall/other entity

[stonedegg]

I want to spawn a prop_physics in the air and check when it's hitting the ground / a wall or any other entity. Is there a clean way to do so?
For the ground check, I have tried m_hGroundEntity, but it always returns 0 no matter what. (game csgo)
Thanks for any help.

[stonedegg]

Found a really nice solution, it's the property "m_bFirstCollisionAfterLaunch". Will be automatically set to False as soon as the prop_physics collides for the first time.