Giving an object "mass"

[MCF]

Here is my situation.  I have a long perspective hallway as one of my rooms.  The character basically can only walk on the vertical axis, scaling down in the distance.  I have an chandelier object that, when activated, decends to the floor in the foreground.

Problem 1) The character can walk right through the object when it's on the floor.  I suppose I could cut out a little walkable space, but that would limit the characters movement inexplicably when the chandelier is in the air.  How can I give the object "mass" so that the character cannot walk through it?

This is more than an issue with the baseline, since I can easily set that at the extreme foreground.

I guess what I need is the ability to change the walkable area in the room -- or do I need to change to a new room when the chandelier is on the floor?

[Scummbuddy]

you should have the following.  

a bg image
an object image with the chandilier above
an animation of the chandilier falling
an object image with the chandilier crashed
at least 3 walkable areas (one below the chandiliers falling area, one including where the chandilier will fall, plus a little around it, and one above it)

youll need an if statement to check if the object image for when its crashed is on, and if so, then removewalkablearea around chandilier