phong shading errors in bakes

Ged

Im trying to bake a simple window model and its coming out with these wierd shading errors, basically it looks like its showing all the triangles that make up the lowpoly in a very subtle way. It doesnt look too bad in xnormal but it looks terrible in other engines. Any idea how I might fix this? Im currently working in cinema4d and exporting to wavefront from there but I tried exporting to 3ds and it gave the same result, Im not sure its exporting the phong tag information

Eric Chadwick

Looks to me like the vertices are being duplicated in the OBJ file. I know some programs do this wherever there's a UV seam.

Ged

EricChadwick wrote: »

Looks to me like the vertices are being duplicated in the OBJ file. I know some programs do this wherever there's a UV seam.

thanks Eric maybe thats what it is, is there any way to fix this problem? I suppose I just need a better obj exporter.
tried using the riptide exporter for c4d objs and the errors are still there

Eric Chadwick

Does Xnormal have an auto-weld function, maybe an import setting? Maybe look for a different export format that Xnormal supports (or use a different baker).

The .3ds format is always going to have problems though, it cannot store a UV seam in a single mesh vertex, so it either tosses it out or it dupes the vert (can't remember which).

Ged

well problem fixed, all I did was import the obj that I got out of c4d into max, then set the smoothing groups to auto and export and the bake is perfect, this is very annoying, I wonder if someone has made a good exporter for c4d which keeps all the correct phong tags and doesnt duplicate verts or anything.

Eric Chadwick

Glad you sorted it out.

This isn't related to Phong though, OBJ doesn't store material data at all unless you're also creating a MTL file on export, and even then it doesn't store the shading model (Phong, Blinn, etc.)

Your issue was caused by the mesh itself... vertex normals, duplicated verts, whatever.

Ged

EricChadwick wrote: »

Glad you sorted it out.
Your issue was caused by the mesh itself... vertex normals, duplicated verts, whatever.

ah I thought that smoothing groups and phong tags were similar things but youre saying one is using vertex normals to control shading which is exported and one is using a shader setting which is not exported?

Eric Chadwick

Correct.

Smoothing groups are simply a way to control vertex normals. Smoothing groups are meant to simplify editing vertex normals, but I think they actually make vertex normals harder to understand.

Vertex normals are a mesh-specific control. Phong is a shader-specific setting. They both control the "smoothness" of the model, but at different ends.

Ged

EricChadwick wrote: »

Correct.
Smoothing groups are simply a way to control vertex normals. Smoothing groups are meant to simplify editing vertex normals, but I think they actually make vertex normals harder to understand.

well then I can only assume that cinema 4d has no way of editing smoothing groups and therefore is inferior to apps like 3ds when it comes to game models and texture baking

Eric Chadwick

I don't know C4D well enough, but applying a Phong break to an edge sounds like the same result as using 3ds Max to assign different smoothing groups on either side of an edge.

http://www.polycount.com/forum/showthread.php?t=56935