Extra lines and artefacts visible when rendering

Dear friends,

When I'm in reder view mode, there are lots of extra lines (like it's a wireframe) and strange artifacts on the model. 

artifacs visible at the left:

Under this arfifacts, even the texture is not visible (in Cycles, in Eevee it's more or less ok). 

Why is it so?

  • spikeyxxx replied

    That's weird. Could it have something to do with the fact that you imported this model? (Did you use Collada (.dae)?)

     I only use Blender, so I do not know anything about importing and exporting, apart from fearing it;)

    (Hopefully USD will improve the situation.)

  • Shawn Blanch(blanchsb) replied

    hhappybirthday

    I'm proud to be a dear friend haha.
    Is there a chance that you have modified the WireFrame settings in the Viewport Overlays?
    I get similar results when I play with that. Usually I have it turned off completely.