Static Mesh collisions and textures of custom static world mesh?

I am relatively new to modding Simpsons Hit and Run and am wondering if there is a way to import custom collision meshes into a .p3d file and if so what file format would be used to do so? i had custom world mesh's using .obj in blender but can't figure out how to export textures that can be imported into .p3d as the default .mtl file is not supported. I was just wondering if anyone can offer me some help?

Users are unable to create custom maps at this time. There's no way to do it using the Pure3D Editor.