Irrlicht Engine

i'm learning in first person shooting.but i've some problem. there are...

-why i'm stuck to walk pass the narrow way and stair in Q3map. and it's very difficult to walk pass a slope way.
-What's the problem with "CreateCollisionResponseAnimator" which we use for collision detection between map and camera ? because its moving are quite slow and not smoothly.
-Sould i use some physics engines for better collision detection such as newton? Could it help ?

please tell me ,thank.

I was falling through terrain, so I did a forum search and the answer appeared to be "use Newton" instead of the built-in collision detection.

I haven't had the time to try and implement it yet though.