blender to unity error I am modeling some objects in blender 2.79 for a unity game. I can import the model perfectly and I also can see textures... There is just one error in unity shown up: "A polygon of [modelname] is self-intersecting and has been discarded.". This error effects, that the model can't get a meshcollider (hitbox exactly fitting to the model). I found out, that it's  often not working when I fill more vertices than 4. For example like this: 



But that might be wrong also. I already removed doubles and the error still appears in unity. Could anyone tell me please how I can avoid that error or at least get the hitbox correctly? Thank you for your help! For more questions about the problem -> just ask me in the comments :P
Based on what I see in the image you posted and as you said yourself, the main problem is the fact that your model has N-gons, which is a polygon made of 5 or more vertices, in your case that is the top face. Unity actually struggles with N-gons, so it is best to make the model with only Quads and/or Triangles. Try deleting the top face and make two faces like the ones you have on the front of your model. To make sure this is actually the problem, check if the black dot on the top face is actually at the center of that face, if not you definitely have an N-gon there. Otherwise (=if the black dot is in the center of the face) the problem could also be that the middle vertex on the top (red circle in the image below) might not be attached to the top face. Either way the ideal solution should be creating two top faces like the one I highlighted in the image below.