I'm having difficulty of solving this problem. I'm making a high poly truck, though there are some shadow lines trying to fix up haven't figured it out just yet. This is my first vehicle model trying to make and in a sense, I think I kinda screw up the model a little bit as the UV unwrapping is kinda a mess, though I believe it isn't the way UV is set up because I have two different UV maps, it still shows the shadow outlines in solid mode, and I've moved the lighting around. If anyone knows the answer to this, or have a similar situation would be greatly appreciated.


Rendered with shadow lines

Wireframe picture

  • 1
    $\begingroup$ This is clearly mesh issue. You have there many ngons (faces with over 4 vertices). You should model it with quads (ever face with 4 vertices). $\endgroup$
    – cgslav
    Commented Aug 15, 2016 at 4:30

1 Answer 1


As LukeD commented, meshes should consist of quads of roughly the same size. A standard way of rendering faces is to take a color assigned to a given vertex of the face and linearly interpolate the color across the face to the next vertex. So if your faces are not roughly uniform in size, you can get these long shadows stretching across the surface of your model.

Basically, the lights in your blender editor illuminate the vertices. If one vertex of a face is very far from another vertex, the vert farther from the light will be assigned a darker color, and the "color gradient" across the long face is very noticeable (because it's just evenly blending the colors of the vertices across the face). If you add more polys, there will be more vertices to illuminate, which will give more accurate coloring.

  • $\begingroup$ The issue is not so much the ngons but the fact that they are non-planar. Planes can only bend so much before they need some real geometry to describe the curves. Read:: blender.stackexchange.com/questions/23600/… and blender.stackexchange.com/questions/56755/… $\endgroup$
    – user1853
    Commented Aug 15, 2016 at 7:00
  • $\begingroup$ Okay so for your suggestion would it be best of trying to fix it, or completely redo the model and use my other one as an size reference, if redoing it what would be the best option of doing the workflow to avoid this happening again? I'm looking at tutorials with Topology workflow and thinking of redoing the model as right now its a tedious slow job of fixing up. $\endgroup$
    – S1ayer450
    Commented Aug 15, 2016 at 18:45
  • $\begingroup$ @S1ayer450 I can't say; it really depends on your needs. Also, I've never really tried to model a vehicle. If you decide to redo it, maybe check out other models of trucks to see what their quads look like. Check out the links that cegaton posted, too: maybe you can fix this model by flipping some edges. Good luck. $\endgroup$
    – yoshi
    Commented Aug 15, 2016 at 20:09
  • $\begingroup$ Okay I appreacheate your honesty, I've ended up having to redo the body frame work, have mostly quad faces, looked up about topology and tried a different workflow with subdivide. Now UV unwrapping is much easier now and there isn't any faces that are overlapping with each other unlike the last one which was a big mess. Thanks for the advices and links everyone! $\endgroup$
    – S1ayer450
    Commented Aug 16, 2016 at 5:11

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