Superku@ things getting more clear now, thank you man, I appreciate your help.

Edit: one more question, related to collusion with doors. when you walk towards the corners of the door:

Movement gets jerking, why is that? Shouldn't POLYGON fix this kind of collusion problems with models?
I can see that there is that pit, on the edges, where player gets stuck. But he is like bouncing when I walk towards it?

I would really appreciate, if someone could give me some explanation about this issue as well.


Edit2: I could fix this problem by making the door slightly thicker, so that pit differences between wall and door a is gone, but it doesn't really look good, as door become giant!