I would like to know how to fix the problem with "back-face culling", check this photo.

enter image description here

In my 3D viewport you can see the right window in Unity has a problem, you can as spectator see the inside of the pipe, however in front view (left window in the picture) the interior faces are ok .

So my first steps in Blender were

  1. Check the display to "GLSL" (Blender Internal)
  2. Go into Edit Mode and flip the normals of all the mesh (press W > Flip Normals on all mesh objects).
  3. Once I've flipped all the normals I activate the option Back-face Culling in the N panel
  4. Apply the transformation .
  5. Unwrap the model (check marked seams if possible and space for texture bleeding)
  6. Export in FBX/OBJ files to the game engine.

I would like to know how to fix back-face culling for cylinders objects.

  • 1
    $\begingroup$ You should not blindly be flipping normals, you shouls instead make them consistent instead with Ctrl+N $\endgroup$ Apr 3, 2017 at 23:13
  • $\begingroup$ "control + n" instead of using "w" for flpped the normals? $\endgroup$
    – RG1988
    Apr 4, 2017 at 1:18
  • 1
    $\begingroup$ Ctrl+NIn Edit Mode > Make Normals Consistent $\endgroup$ Apr 4, 2017 at 1:56
  • $\begingroup$ for this case, a cylinder , should I select all the faces to flipped? or just chosen areas, In this model I ve use "A" keyboard to select all the faces and then...well "control + N " as you said before. $\endgroup$
    – RG1988
    Apr 4, 2017 at 15:29
  • $\begingroup$ That should about do it. Make Normals Consistent operator works best on a whole mesh at once, provided the mesh is manifold and consistently modeled $\endgroup$ Apr 4, 2017 at 22:24

1 Answer 1


Blender's show back faces option is just for viewport purposes and doesn't effect export. The easiest solution is to duplicate the faces of your pipe, flip the normals on the copy, and keep both overlaid. Alternatively you can find or make a Unity shader that shows back faces.

  • $\begingroup$ Just to add: Showing backfaces in Unity is better performance, but the real issue is if you need different lighting for both sides, in which case a two-sided mesh is better. A one-sided no-cull mesh is going to show the same lighting on both sides. $\endgroup$
    – Nathan
    Apr 20, 2021 at 17:38

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