AO Bake in Max

Oniram

Hey all. typically i do not get this problem, though i do run into it from time to time. im rendering out a normal and AO map for an object (if it matters, the high poly was done in zbrush). the normal map comes out perfectly.. and quick too. when i switch to ao however, using the Ambeint/Occlusion material with 100% self illumination.. the ao render comes out almost all white. no matter what settings i change, the result is almost always the same. samples just increases the time, as expected.. but i put the samples to 1 and it took as long as it did when it was 16. i can up the spread to about 2 before i start getting VERY dark areas. i tried experimenting with the spread at 10, and it still didnt give me what i wanted. as ive said before this setup usually works for me, but i keep having this problem every now and then and id like to get to the bottom of it. any help would be great.

cholden

Try going to top menu > Rendering > Light Tracer > Then check the Active box next to Light Tracer. Even if it's on, uncheck it and check it back on just to be sure.

Psyk0

using the Ambeint/Occlusion material with 100% self illumination

You mean, standard material set to white...not 100% self illuminated, right?

Oniram

no no. i have the diffuse slot with an ambient occlusion material (the first one on the top of the list with mental ray) and self illum set to 100. then i put that as a process overlay so it gets applied to everything. one of the methods described here:

Method 3:
http://www.laurenscorijn.com/articles/ambient-occlusion-baking

@cholden: im using mental ray.. so light tracer isnt an option

Xenobond

if you're using mental ray, just add the ambient occlusion map in the RTT dialog. It ignores the material settings.

Mark Dygert

Xenobond wrote: »

if you're using mental ray, just add the ambient occlusion map in the RTT dialog. It ignores the material settings.

^This

The A/O Material is for if you're rendering the scene.

Oniram

ok. well regardless that doesnt work either. for now i think i might just grab an AO from crazybump, based off of the normal. when i get back to my school on tuesday ill ask one of my instructors.

Mr. Bean

Oniram wrote: »

ok. well regardless that doesnt work either. for now i think i might just grab an AO from crazybump, based off of the normal. when i get back to my school on tuesday ill ask one of my instructors.

Wait, did you throw in a skylight? You really should try that; I always put in a skylight. It makes a difference. See if that works.

Oniram

yup. ive tried the following methods.

Scanline with light tracer.
Scanline with skylight (no light tracer).
mental ray AO RTT with and without material. i will post up my files in a bit to show u all whats going on.

Oniram

The High Poly Model.. so we know what we're dealing with


This is the normal map.. looks good.. needs tweaks but it captures the detail.



This is pretty much the AO i get when trying to RTT

pior

This looks like a perfect AO bake to me!!
What's wrong with it ?

Mark Dygert

That looks exactly like it should.

MoP

Yes, that looks fine, what else were you expecting? It's ambient occlusion.

Oniram

it needs more detail. look at the ammount of detail captured from the normal.. underneath the eyes.. the "wrinkles on the back. it seems as if its not capturing all of the AO that it should.

roosterMAP

this question seemed appropriate in this thread. whenever i bake normals and AO's, the lines are always pixelated. is there some kind of antialiasing i can activate in 3ds max?

MoP

roosterMAP: You can turn on Supersampling. It's in the Render settings.

Mr. Bean

Oniram wrote: »

it needs more detail. look at the ammount of detail captured from the normal.. underneath the eyes.. the "wrinkles on the back. it seems as if its not capturing all of the AO that it should.

Well, that's because it's a normal map. The normal map is supposed to capture all of the detail possible, whereas the AO map is more for baking subtle lighting information into the texture. Try playing around with the lights in your scene, or in Photoshop (or whatever is your paint program) try upping the contrast. Perhaps the details are there, you just need to bring it out.

Oniram

hmm. maybe it is just a matter of the detail being too subtle. though just as a test, i turned up the spread to 40, and the samples to 256, and surprisingly i still saw pixelated sampling on the model. i think i may be able to make due with that map though, after some photohsop tweaking

Mark Dygert

Oniram wrote: »

it needs more detail. look at the ammount of detail captured from the normal.. underneath the eyes.. the "wrinkles on the back. it seems as if its not capturing all of the AO that it should.

There isn't that much to the model. It captured some of that detail, crank up the contrast and turn down the brightness in photoshop to see it. However there isn't that much to the surface to really occlude that much. It's behaving as it should. Often to get the bakes to turn out like you want you need to exaggerate the details.

Oniram

yeah. i guess it was all just a matter of fact that there wasnt really any concave shape to the model that would add any shadows.. after playing around with levels and such in PS i was able to get something decent. Anyway i figure since thats all done now i can show what i was going through all of this for.