what the ambient, diffusive, specular, and emissive tabs do in milkshape ?
if you know feel free to tell me :)

heres a pic :P

I don't know. I don't think the half-life engine supports them.

no clue. but i tend to go with the saying "if you dont know what it is, test it in a safe environment"

They're material attributes, though I'm not familiar with all of the names. ambient and diffuse are light and shadow on the material, respectively. Specular has to do with the highlights, but I'm not sure what emissive is, as I've not heard that term before.

Emissive is moreso self-illumination.