Grimrock

What exactly is the 'ItemConstrainBox' class used for. I have seen it in various definitions but can't quite see what it does.

If the party moves on a tile with an item on, this item could be pushed forwards to the edge of the tile. If there is a model on that edge (eg. some decoration) the item gets pushed into that model, which looks awful or even worse, makes the item vanish and hard to pick up again.

The ItemConstrainBox draws a box around a model which prevents an item from getting pushed into it.