That PASSABLE issue sounds pretty weird for me so I did some tests. It seems that when you set an entity as passable in WED, it prevents the engine to compute the collision hull of the entity. If you try to change the PASSABLE flag, it is actually changed but has no effect. Every FAT & NARROW, min & max, changes has no effect too. Calling 'c_updatehull' builds entity's collision hull and makes it behave normally. So I guess it has something to do with the lack of a collision hull. Checking BBOX on WED, as well as calling 'c_setminmax', should force the engine to compute the entity's collision hull, but it does not. I guess this 'c_setminmax' behaviour is actually a bug. Will it ever be fixed? That is another story.