I’m attempting to import models created in Blender 2.61 into Unity, but they are becoming distorted, missing faces, etc.
-Using Blender 2.61
-Same output for .blend files and exported to .fbx
-new BlenderToFBX python script added to the Unity directory
-I’ve downgraded to blender 2.59, 2.57, and no avail.
-I’ve tested with importing a simple cube model from Blender, and it seems to work just fine.
I’ve attached screenshots of the models I’m attempting to import, and what they end up looking like when scaled up in Unity.
Any idea what is going on here? I’ve spent a couple hours troubleshooting last night, but I’m at a complete loss as to why this keeps happening.
Are you sure the faces are missing, and aren’t just flipped? It looks lik you’ve got a backwards face and a lot of messed up normals.
Looks like a normals problem to me. You may be able to correct it by reimporting it and selecting to automatically recalculate normals. But since it is YOUR model I prefer to correct the issue at the source. Simply select your model in edit mode, high light all faces and hit CTRL+N.
Blender renders a face on both sides, while Unity (being a game engine) renders faces only facing “outwards”. You can select to visually see what direction your normals are facing in Blender by enabling an option in Blender’s Viewport Properties (Press N on the 3D ViewPort). I believe under “display” you will find check boxes to see what direction your normals are facing. For this you probably just want to see the “Face” and not the “Vertex” normal.
Thank you guys, that seems to be the problem (I’m very new to 3d modeling in general). There seems to be no consistency in which faces are messed up, any way that I can prevent this in the future?
Blender makes its “best guess” based on the surrounding faces, but doesn’t always get it right. Mirroring and Extruding and other actions can confuse Blender. It’s normally not a huge issue, but one to keep on top of and fix as one goes along. Often the face doesn’t show until you are in “Viewport Shading/Texure” mode:
Even without a texture applied, you will be able to see if the face is visible or not.
Solution : TAB (edit mode) => A twice (to select everything) => CTRL + N and for the cube delete the in faces
to adjust the normals or something like that
the cause of this problem : The Circle choose random outs and ins
i hope that helps and right 
There are steps to take to prevent this from occurring but honestly it is more productive to just focus on building your model, then when it looks good, Ctrl+N the whole thing
EDIT: Just an FYI generally normals are backwards depending on what direction they are facing. The way you determin direction is if you selected the vertices to create your triangle in a left circle or right circle. If your selection went counter clockwise then the face will point outwards, clockwise however and it will point inwards. This is standard for most graphics libraries such as OpenGL and DirectX. I’m actually not sure if this works for blender as some times blender just does things… BUT it was the case when I was working with 3D studio max. Recalculate normals has spoiled me…
Make sure nothing is overlapping D:
