Hidden Lines in a 3d document

[Andeol_b]

Hey guys!

I've got a problem with my pln. file. Since a few days my surface snapping isn't working properly and now I've got some problems with the hidden lines in a 3D document. In the parameters of the the 3d documents, the hidden lines a turned off but some still appears. I want to make perspective section but I don't know how to solve my problem... Any tipps?