Hi Nikola, one thing is you should generally avoid using 3DS format, try using OBJ format instead.

3DS is a very old file format, it was part of the old original MS-DOS version of 3D Studio (not 3DS "Max"), and it has various limitations in the format itself, one of which is no way to have vertex normals smoothing information included in the file. When you can get vertex normals going through into your rendering it usually helps quite a bit.

But also with the kind of thing that you have there on the crown of your phone model, that's probably some kind of problem in the model itself, I think it's likely that if you zoom in to that area in MoI you'll probably see the surface is probably kind of bunched up awkwardly or folded over back on top of itself in a small area near the tip. That can happen if you do a revolve with a profile that's not quite planar or the revolve axis is slightly off or some of the curves that you used for a sweep did not quite touch each other end-to-end exactly or things like that.

I'll take a look at your model to try and zero in on the problem area.

- Michael