I've been using Unity for about 8 months or so (I don't have a good sense of time), and I haven't really had much like trying to make levels out of objects made entirely in Blender...I mean I do fine with objecst like painting, shelves, doors, etc, but as for walls and ceilings, I haven't had much luck.

So I made another project in Unity to make those parts. I modelled it after Pie in the sky's GCS 3.0, not Doom, but the basic idea is much like Doom- using nothing but Planes for walls, floors, and ceilings. It doens't make real materials (you'd have to remake them in Unity anyway, so why bother?)

I've got everything working except for the normals. The walls are supposed to be two-sided, the floors only to be seen from above, and the ceilings to be seen from below...

The ceilings are acting like floors. The walls aren't working either, but I figure if I can find out what I'm doing wrong with the ceiling, I'll be able to fix the wall.

Can someone take a quick look at the .obj and tell me where I've gone wrong?

I'd appreciate it.

.obj: https://drive.google.com/file/d/0BwFIWa8-uYIhdGktRUNKVWJzNFE/edit?usp=sharing

.mtl: https://drive.google.com/file/d/0BwFIWa8-uYIhUmotMEJwaGVyZWs/edit?usp=sharing

Doubt you need the .mtl, but I thought I should include it just in case.

Generally this is an vertex winding issue. You need to reorder the vertices of the triangles that are facing the wrong way. Since you mention blender, I think a simple method would be to import the obj file in blender, hit tab to go to edit mode, select the faces (alt tab switches from vertex, to edge, to face select mode) that are backwards, and click normals->flip direction on the left hand tool bar. Then export the edited mesh and reload in unity. As for the walls, to be 2 sided they will need triangles facing both directions. if you hit n in the main window another tool bar will pop up on the right, scroll down to mesh display, and click the face button under "normals:" ( not the faces checkbox under "overlays:") This will show you what direction the faces face based on their current winding. you should see a normal pointing in both directions of the walls, and down for the ceiling and up for the floors. If this doesn't fix it, then blender and unity are using opposite handedness, and reversing the direction of all normals will fix it.

First sentence answered my question (at least with the ceilings)

Thanks so much. It worked. ^^

First sentence answered my question (at least with the ceilings)

Thanks so much. It worked. ^^

It's always a guess as to how detailed an answer to give, glad i could help.