Iacov, on 19 December 2015 - 11:35 AM, said:
thanks a lot

only thing is, that as soon as i remove doubles and turn tris to quads, the model looks like this:

i guess its just a visual thing, without influencing the actual model - but does anyone know what's causing this?
best
I'm no expert when it comes to using blender, in fact I don't really know how to use blender at all. But I usually come across this problem in 3ds max and it's caused by messed up UV facing in your model. The way I would fix this, in 3ds max at least, is to just break up all the vertices and then re-weld them back together. Otherwise, you could always just try to re-import the model from scratch using slightly different import settings.