Hi Andy,
If the normals arent pointing in the "right direction", it might be an indicator that you dont have a "solid" and only surfaces or joined surfaces, which would not have a "right direction"...

Yes they are only joined surfaces, but I've never had a problem with exporting joined surfaces before.

It seems I found a work around though, exporting as an LWO works properly and doesn't flip the polygons. That doesn't really make sense to me since it's the same meshing algorithm, but I can't argue with the fact that one is working and one isn't.

Hi Andy,

If you are using .obj to export geomtry into modo, you can have troubles with ngones badly triangulated, and some faces can be flipped.

Complete reversed surfaces can happend with non solid geometry like Burr discribe.

Pay attention that MoI creates double side surfaces automatically for single surfaces when using .lwo (check the modo shader tree)

That's maybe why the object looks right using this format.

Hi Andy - if your objects are not a closed solid then it is pretty much arbitrary which side happens to be the positive normal direction. It will vary depending on things like if you drew one of the original generator curves in a clockwise or counter-clockwise direction.

It's usually best to just use double-sided lighting in your rendering program so that you don't have to worry about which side of an open surface happens to be the positive surface normal direction.

You can use the Flip command in MoI to flip an open surface so that its positive normal will be pointing in the opposite direction too though:
http://moi3d.com/2.0/docs/moi_command_reference10.htm#flip

After you run the Flip command the objects that were flipped will generate a mesh with opposite normals from before.

- Michael

Hi Andy and yes like PaQ mentions if you're transferring into Modo I'd recommend LWO format and not OBJ - the data in LWO is the closest to how Modo structures things internally itself and so its LWO importer doesn't really mess around with stuff. Modo's OBJ importer has improved in recent releases but still kind of has a ways to go with handling n-gons.

- Michael

Yep that is why the lwo looked good. I realized that after taking it into 3D Max and it still looked bad.

Indeed, it looks like double sided materials are my best option at this point. I was hoping to avoid them since I have had trouble with them in Max, but I think it's the only way I am going to get these models into Max.

Hi Andy - for going into Max your best bet is probably exporting to FBX format out of MoI.

If you need single-sided lighting, then it is possible to use the Flip command in MoI to flip pieces that you need to have reversed before doing the export.

But for regular renderings just using double sided lighting should solve the problem without any extra messing around.

- Michael

Ah yes the flip command. I thought I had remembered there being one but couldn't find it anywhere, I remember now that it was not mapped to a button.