Blender -> Unity Export/Import via FBX produces broken mesh

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1

Greetings,

So, i’ve made a fairly simple mesh in blender. Looks great.

I save the file, then separately export to FBX (which also proceeds normally).

I then take my FBX and add to my project repository in Unity.

Looking at the mesh in unity’s preview box, the mesh is totally broken. I can see inside mesh objects that I know perfectly well were capped in Blender. Doing simple beveling also produces a crappy mesh in blender.

It does not seem to me that blender is the culprit. I have tried three versions (2.42, 2.49a and 2.57). They all produce this behavior. But I am posting here as well as on the Unity forum so that I can investigate both sides of the issue.

Now I’m the 1st to admit Im no Blender expert, but I’ve followed several key tutorials on the subject, and what I am doing is well within the realm of basic. Nothing fancy is going on with my meshes. Basically I take a rectangle, stretch it out, bevel the edges and export. Once into Unity, bam! Broken mesh.

I’ve experimented with the Unity import options, and have managed to improve the quality (more defined corners versus lousy rounded edges, etc). I’ve calculated the normals (versus importing them), and I’ve messed with scale. There are also no animations, so I turn that option off.

As far as the EXPORT via FBX from blender, I’m disabling the export of lamp, camera and empty objects, and explicitly disabling animation from being exported (as there IS no animation). Again, the mesh looks exactly as I designed it in Blender. The problems only occur when bringing into Unity. But I don’t know for a fact that it IS Unity that is the culprit, though it SEEMS to be the case.

I’ve experimented with using non-FBX formats (obj, 3ds, etc). Same deal.

What am I doing wrong on the Blender side, if anything? Would love to know =P

Thanks…

subcon

2

It really sounds like normals are pointing the wrong way but that’s hard to say as you didn’t provide a screenshot. Switch to textured view (GLSL) in Blender and you should see your model the way it is.

And you don’t say what “broken” is. If you mean that you lost sharp edges it might be because you didn’t define any sharp edges and didn’t use edge split modifier.

You may also have double vertices if you used mirror modifier without cutting stuff etc.

edit: You have to use double edges (define sharp edge + edge split modifier in Blender) as that is how sharp edges are really drawn: piece of geometry is separated from the whole. Smooth a model and press “y” to separate selected faces and you’ll see.

3

Ah, so it IS something with Blender and not Unity …

Here is an example. The object is in GLSL mode, and has the holes I mentioned.

http://www.americancleanair.com/wings.jpg

What I need to know is how to make those holes go away. The mesh is supposed to appear solid, not hollow.

Thanks for your help!

4

OK, problem resolved.

You were right - my normals were flipped inappropriately.

Individually selecting the portions of the mesh, and activating ‘flip normals’, seems to have resolved the issue.

Thank you