How odd, export to .obj and import it and see if there's an improvement.
How and when did it come like that? It could be a normals problem, if you can find away to turn on back face culling, then turn it on, if you find holes in the mesh or some irregularities (as bf culling only renders one side of the polygon) of the models then some of them (or all) of them are the wrong way round, in Cinema 4D this is usually fixed by selecting all of the polygons and using a command called 'align normals' if 3D studio doesn't have this then you'd need to select the 'afflicted' faces and use 'flip normals' or 'reverse normals' or whatever it may be called in the application.
Though it doesn't look like that problem, or at least from my experience upside down normals don't create that effect, but it does look like a problem with the normals...
Of course, you could try something else, that it to 'optimise your model', now this goes under different names in different applications, it basically 'corrects' any mesh and normal problems caused when porting models between programs and other situations. In Cinema 4D the command is called 'Optimize' and in Milkshape it is called 'Clean Model' so in 3D Studio if it has it, then look for something along those lines.
I shot the sheriff
