Baking AO in Maya

[hellclad]

This is something that happens when I try to bake AO using mental ray...

http://i.imgur.com/N22JU01.png

 

Not sure why this is caused. I've been going abck and forth between blender and maya to bake an AO but I would like to fully just be able to convert over to maya now. If anyone has any ideas or knows anything about this please let me in on it. Thanks for all the help everyone has been before on these forums too.

 

Edit: http://i.imgur.com/xnMJWhU.png My mental ray settings.

[hellclad]

Bump, if anyone has any idea at all, please let me know <3

[MIstahMoose]

lol theres no bumping on this forum.

What does your unwrap look like?

[Cathy Foil]

Hi Hellclad,
Your settings look OK though here is a link to step by step instructions on how to bake AO in Maya.
http://www.game-artist.net/forums/spotlight-articles/1317-tutorial-ambient-occlusion-maya-alchemist101.html

It is for an older version of Maya but I am sure things haven't changed that much.

Judging by the photo you posted it looks like you may have some overlapping UVs or UVs that are not inside the UV range.

Hope that helps.
Cathy

 

 

[hellclad]

Unwrap : http://i.imgur.com/aEIKyfH.png

 

 No overlapping or anything, just doesn't want to cooperate.

[Cathy Foil]

Make sure you normals are facing outside.  The darker areas look like they might be pointed inside.  The lighter colored area on the right side of the shirt under the arm looks right.

Turn on Backface Culling under Shading.  That will show you right away if you have any faces that are facing the wrong direction.

[hellclad]

Nope, they're all faced the right direction, when I turned off double sided rendering still the same. :\

 

http://imgur.com/a/lD3TW

 

with culling

[Drongle McMahon]

Any chance your garment has inside and outside surfaces, and if so that their UV maps are superimposed? This happens in Blender if you use "solidify", and then the inside and outside bakes are made on top of each other. Which one of inside or outside AO you see in a particular place then depends on the order that the triangles get baked in. If this is the case, you need to move the UV maps so that they don't overlap, or do the bake from a model with the inside deleted.

[hellclad]

Nope, it's only one sided, I don't mirror polygons until I'm 100% through with everything getting touched up.

[Cathy Foil]

Try exporting the your mesh out as an OBJ.  Then import it back into a new scene.

Bake a new AO onto the imported OBJ see if that works.

[hellclad]

Thank you Cathy that seems to have mostly fixed my issue. But I still get these dark lines around seams.

 

http://i.imgur.com/HG2tbVr.png

 

I turned the fill to 3, but I feel it kinda made it look unnatural and mess up around some other parts, is there another setting I should try adjusting?

[Cathy Foil]

Your welcome Hellclad.

I would set the "Fill Texture Seams" setting to more than just 3.0 in your "Texture Bake Set Override" to more than 3.0 if you are still getting black bleed lines showing up.

What increasing the Fill Texture Seams setting does is increases the AO coloring past the edges of the UV boarders.  I used to work in the printing industry and we could set the color of the ink to go past where the pages where to be cut this was called the bleed.  This way when the pages where cut and trimmed the color went all the way to the edge of the page.

It is the same idea for the Fill Texture Seam.  The color or shading of the AO is bleed past the edges of the UV boarders where the UV pattern cuts the AO texture.

Looking at your UV layout you can see near at the top of the UVs from the neck hole to the ends of the short sleeves the UVs are bunched up very close together.  This makes it harder to Maya to create an accurate shading texture.  It be a good idea to spread them out.  Same goes for under the sleeves and arm pit area.

You still need a good bleed on the shading by increasing the Fill Texture Seams setting.  You can also bring the texture into Photoshop and manually clone the edges to increase the bleed.

Even if you adjusted your UVs so that in Maya you didn't need any bleed they would still show up in SL because when you upload a texture to SL it gets converted into a different format and the process slightly blurs the image.  Also as you pull back the camera in SL the viewer does something to either the texture by changing it's resolution or doesn't keep the UVs as accurate as when you are close up.  I am not sure which.  In any event if you have no bleed and pull away dark seams will show up on your mesh.  They come from the black background where in your texture your shading stops.  If you had a white back ground or green background your to your AO texture the seams that would show up would be those colors instead of black.

You are almost there!

A fast way to adjust your UVs is to select your mesh in object mode.  THen open up your UV TExture Editor and then hold down your right mouse button till the option to select UVs came up.  THen select all the UVs.  THen click on the Polygons menu in the UV Texture Editor and go down to "Relax" and open up the options window.  In the "Relax UVs Options" window put a check mark next to "Pin UV border" and under "Other Settings" select "World space" and set Maximum iterations: to 6 or more.  Click apply a few times.  You will get a much better even UV layout with less distortions.

Let me know if that helps.
Cathy