Ambient Occlusion baking in Maya

tanka

Hey guys, I'm a bit of a texturing noob, and I am trying to master the art of baking hi res meshes to low res meshes. I've followed a few tutorials online and read up on alot of information but my AO bakes never seem to look right.

I did an experiement with a plane with a raised cross on it (to save rendering time) and I can't seem to make the bake look right. Everytime I try it comes out too bright and very grainy, regardless of how high I adjust the bake settings. (See below)




Am I missing something? I believe I'm following the tutorials correctly.. The only thing I can think of is I'm not tweaking the offset properly or something.. But I've played around with it quite a bit.

Can anybody help me?

Thanks guys!

kodde

What tutorial?
Transfer Map or Batch Bake (Mental Ray)? I am guessing Transfer Map since you stated this:

tanka wrote: »

Hey guys, I'm a bit of a texturing noob, and I am trying to master the art of baking hi res meshes to low res meshes. Thanks guys!

tanka

Ah yeah, Probably should of mentioned that.. I'm using transfer maps.

The tutorials I've been looking at are the Eat3D Pillar tutorial (which is for max), The making of Varga tutorial (http://www.paultosca.com/makingofvarga.html) and a few others I stumbled across. Those two are the main ones though.

nome_sane

The results look more like a cross depression than a raised cross.

Are the high-poly, source plane and cross separate meshes?
If they are are they both added to the source mesh list?

Also try checking the normals of your geometry.

Your grainynessness could be alleviated with more samples.

tanka

It's the same mesh, and it is in the source mesh list.. It's also on the highest sampling quality, so I have no idea where the grain is coming from.

I will check out the normals, but the biggest problem is grain and the brightness, and I have no idea what's causing them.

nome_sane

Sorry I should have been more specific. I meant occlusions samples.

In Transfer Maps window there should be a slider for "occlusion rays" I think it defaults to 16 which is quite low. I believe, because the rays are fired at random directions if the number of rays is too low then adjacent pixels can have sharp differences in averaged occlusion values.
Hence a noisy result. Increasing the number of rays gives a more accurate and therefor smother result. But it will increase your render time.

Firebert

I have had much heartache with the AO transfer in Maya. Use xNormal, it is free and excels at total amazing awesomeness. You will have much cleaner results that are very smooth and gradiated. Albeit very slow for gathering occlusion, it is still much better than Maya's AO transfer and very easy to use.

kodde

I've yet to try xNormal, but Maya does a good job if you tell it to do it right. At least for me so far

Can you give us a screenshot of your scene?

The Transfer map way should only produce AO results of the details that differ from the LowMesh <-> HighMesh. Whilst Color->Batch Bake (Mental Ray) will produce baked AO results of the whole mesh (the selected mesh), rather than just the differing details like the Transfer Map does.

Since I don't have all your details on your project and what you are trying to achieve it is hard to say exactly what to do. But give the Batch Bake (Mental Ray) a go. Works good for me.

CheeseOnToast

Mental Ray batch bake is ok, but seriously, learn to use Xnormal. The results are better, and it can handle A LOT more polys than Maya. It'll take about half an hour to learn it, and you won't go back.

rooster

I've got some nice AO from maya before, but its a fecking pain in the arse to set up (the regular transfer maps method is missing some important parameters, in 8.5 at least)

i would reccomend another method

kodde

I've done the Maya AO bake in Maya 2008 just this week, and it's easy as 1-2-4, uhm 3. No but seriously, it's easy.

tanka

@nome_sane, The Occlusion samples were at 255, everything was maxed out but there was absolutely no difference between the preview bake and the high quality bake.

@kodde, I'd give batch bake a go, but from what I've read it is a bit of a hassle. I'll probably only use it if I have to, kind of a last resort.

@rooster, I'm using Maya 8.5. Is it an issue exclusive to this version of maya?

Anyway, I'll look into this xnormal app. It might be what I'm after.

ivars

Looks to me like you might have flipped normals, or objects with negative scale. That would also explain why your texture looks so bright, because it's basically a flat surface, apart from the cross, which will read as an indention and make it render somewhat like you've got it there.

You should post a screen of your scene as well.