If a world matrix and camera matrix are both identity matrices, can they be ommited?

Question

This is a basic question about the need for world and camera space matrices when each are identity matrices. Can they be ommited when calculating a 2D projection? I'm pretty sure that they can, although I seem to be getting strange results when I try to project some 3D points whilst ommiting them, I ask since this might be directly linked to another question:

http://stackoverflow.com/questions/3670340/projecting-a-3d-point-to-2d-screen-space-using-a-perspective-camera-matrix

Thanks

Answer 1

Multiplying a 3D point by an identity matrix will result in the same point (hum, by definition), so I see no need to apply them if you are sure they are identity.