black AO texture piece

hey people.
i have just finished my first 3d model and went to texture it, and a TUT said to do an AO. so i did, followed the instructions and it gives the top of my model (almost a third of the model) a black…well, texture. i read somewhere that having some stuff in negatives can cause it, and i changed it, but alas.
http://img205.imageshack.us/img205/434/helpcozihurrdurr.png

Are you sure all normals, where black, point outwards? In edit mode, N-panel Mesh Display, Normals, check Face and see.

i did that and some tiny light blue lines show up on the outside. i assume thats what you ment
http://img845.imageshack.us/img845/7931/derka.png

Check for overlapping or duplicated faces in same space - I have had that issue before.

Yes, that’s the normals direction and it’s correct in this region. So, faces then…

nope. no duplicate faces ether.

file to vivisect here then… erase all around, leave just that part in a new file. See if it’s still black for you before.

i deleted all the pieces of the gun except the bits that were black, messed around with the mesh a little, and they came right. so i exported the pieces to another file (of same model) and put them in there. but it still does the same thing.

There should be some modelling issue that tricks normals to change directions on some faces when mesh is joined. See for some not needed inside faces. Change to face select mode, z and take a close look.

HEY! thx guys for your help, i flipped the normals around and that seemed to fix it.