[SOLVED] collision detection

hi, i make a racing game.
if my car near the object around the main track, the FPS goes down and sometime make error and said not enough memory.
is that because the object is too many polygon?
i used tree collision for all object in the map

thx for the help

What kind of collision shape are you using for the car?

i use convex hull collision, for the object in the map i use tree collision

i already decrease the polygon of the object in map.
but it still make the the program getting slow.
for the material in object in the map, is that get the effect too?
please...help me.
i'm close too the deadline

the error is like this


Error # : 9
Function : Direct3D9VertexDeclaration::getD3DVertexDeclaration
Description : cannot create D3D9 vertex declaration : Invalid Call


hi, now i know how to solve that
1. the polygon object must decrease, if you're using 3DsMax, use multirest to decrease that.
2. the object material don't be so high, it's make the program slow