black AO maps being rendered?

sir-knight

this is starting to bother me... some of my objects in the scene render black AO maps for no reason... while other objects with the same blank white texture and same settings will render the AO just fine... is there something I'm doing wrong to cause this or is it the angle the light is hitting certain objects? @_@

ivars

have you checked your normals? Sounds like they might be inverted.

sir-knight

when I apply the texture I created, it displays properly, if the normals were flipped, I'd be seeing right through the object wouldn't I?


btw, forgot to mention that I'm using Max8... I really ought to insert that into my sig just to be sure it's not forgotten :P

Eric Chadwick

Which method are you using to light and bake AO?

Mark Dygert

sir-knight wrote: »

when I apply the texture I created, it displays properly, if the normals were flipped, I'd be seeing right through the object wouldn't I?

Only if "BackFace Cull" is turned on. Right click the object in the view port and go Object Properties, check on backface culling.

Also know that your UV layout might have flipped pieces and will render incorrectly even if the faces on the actual model are right facing. Which I think is your problem.

I'm not sure if its in Max8 but in the UVW Editor change to face selection, and go Selection > Select inverted faces and flip the results. If its not there try flipping the pieces giving you trouble and see if they render correctly.

sir-knight

it seems that playing with the environment lighting and changing the base texture to slightly offwhite yields better results without touching anything else.

sir-knight

okay I'm bumping this cause I have another AO related question...

I have a 3000ish triangle model of a suspension piece, and I'm trying to bake an AO pass at 2048^2 for it. The bake went fine until around 90%... took about half an hour to get there, but now it's stuck at 99.9% and that's taken about 2 hours to do that 10%, and it's been stuck at 99.9 for about an hour now.

What's going on with it? Is max known to hang on rendering this stuff? CPU is maxed at 99% and mem usage is moving around like it's doing things.

Should I just cancel it and try and rebake with lower settings?

Eric Chadwick

Yes.

sir-knight

bizzare... for shiggles, I restarted max and with the same settings, rendered again and it finished... maybe there's something wrong with my computer

Mister Sentient

sir-knight wrote: »

bizzare... for shiggles, I restarted max and with the same settings, rendered again and it finished... maybe there's something wrong with my computer

Either that or you are using 3ds max. It's great when it works but a bastard when it wants to be.

Joshua Stubbles

Some other things to try when you get black rendered AO:

- Make sure your UV coords are all at "0" for the W-space (option in the UV window)
- Reset XFORMS
- Make a new object (box, etc) and while it's selected, attach your main object. That resets a lot of junk
- If all else fails, export as OBJ or 3DS and reimport (this will nuke all data)