The Problem With Planar Faces
Some faces created by Extruder with Quad faces
may not be flat. This is due to the fact that quad extruded faces have 4 vertices.
It is not guaranteed that these 4 vertices will be on the same plane.
To check this create a 2x2 TGA file like the following and extrude it
|
V

If you look at the object in wireframe you can see that two flat
triangular faces should have been created instead of one 4
vertex face with a big fold in it. To overcome this use triangular or
adaptive faces.