Lets say I have a panel (prop_dynamic) placed near the wall. I want panel to "detach" from the wall and fall down when I step on it. Is there any way to do it?

Yes, you can parent it to a func_physbox that at the beginning has the flag "Motion Disabled" checked (to later fire it the outptut "EnableMotion"), or even making directly a func_physbox with the shape and look (textures) of a panel

josepezdj wrote:
Yes, you can parent it to a func_physbox that at the beginning has the flag "Motion Disabled" checked (to later fire it the outptut "EnableMotion"), or even making directly a func_physbox with the shape and look (textures) of a panel

Thanks a lot!

The entity phys_convert will turn any entity into a physics entity when activated, so you can have your panel do animations like a prop_dynamic, then suddenly become a prop_physics and fall. I've used it on light bridges before to make them fall off the walls into a pit of goo.