OBJ Format Question - Should be easy

OpenGL OpenGL: Advanced Coding
1

Hi Everyone.

I have been working with the wavefront OBJ file format lately. I am trying to build an OBJ loader.

I am almost done, but have a question about material lib files. I can’t seem to find any documentation on this. Know of any?

The question is what do the following stand for?

newmtl PenMetal
Ka 0 0 0
Kd 0.372549 0.376471 0.423529
Ks 0.745098 0.752941 0.847059
illum 2
Ns 64

“newmtl” is clear enough
Ka = Ambient color.
Kd = Diffuse color.
Ks = Specular color.

Here’s the ones I really need help with:

illum = ???
Ns = ???

Thanks in advance,
Michael

United Binary Software http://mkennedy.101main.com/software

2

I think the Illum is the illumination model - 0 = flat color, 1 = diffuse only, 2 = specular + diffuse… I think… I could be way off.

The Ns is the “shininess” of the material. If I recall WF well enough, it’s the specular exponent.

3

That sounds reasonable. Thanks for the quick reply!

I’ll let you know if I find any “official” documentation on it…

Regards,
Michael