Gravity Prop(well collision)

i looked at the gravity tutorial by [size=1][color=black][font=Arial][size=2]Ilyas Usal
and he/you made the floor restricted in size, and my question is:
is it possible to make it collide with an object?

Thanks in advance :smiley:

[edit] Noticed that the name is Gravity prop…hehe my fault
[/size][/font][/color][/size]