Hi Im having a problem when using textporter and the W mapping depth, sometimes for no reason it chooses to just render gray surfaces instead of the greyscale thing its supposed to do.. does anyone else have this problem, and does anyone know how to solve this problem? Im using max 8.
Well first of all let me explain what W is. As you know that the mapping process is defining which point on the 2D texture image should correspond (map) to which point on the 3D object. So the original and by definition texture mapping is a 2D->3D operation in other words UV->XYZ. But since there's the 3D texture concept (usually the procedural textures) one may want to add another dimension to the texture space to support 3D (solid) textures. then the operation becomes 3D->3D operation.
Defining correspondance between two 3D spaces is a bit more work. If you define the texture coordinates by projection (spherical, planar, cylindirc etc) then this is easy, the 3rd coordinate W becomes the distance of the surface point to the projection geometry. But if you do the mapping by hand, then you usually work on a 2D user interface where you set 2 coordites of the existing 3D XYZ vertices. These two coordinates of are usualy U and V. So you don't set the W at all.
So by looking at the unwrapped 3D geometry image you've sent, the "problem" as you mention probably falls into "wrong expectation" category. What do you expect the W channel to hold? IF you set the mapping by projection that should hold the distance to the projection gizmo. If you do the mapping in any other way then make sure that the mapping sets the W properly as well. if you hand crafted the mapping make sure that you switch to VW and UW modes (little fly-off button on the EditUVW's dlg box) and set the W component as you want too.