Collision detection for Constructor-made interiors in Torque

Hi all,

I'm new to Torque (and Constructor) and have been trying to make a simple Interior for use in-game, as part of a small village set-up i'm trying to make.

I'm having issues with collision detection in Torque - specifically that my hollowed-out interior has none. I've made a door and added a portal but I can still walk through the model when it's placed in Torque in game mode. As i'm a new user, i'm a bit unsure of what to do and am probably missing something really obvious... does anyone have any advice on the matter?

Any help would be greatly appreciated! :-)

Thanks!
-Rich