Getting an AO map out of Floating geometry

fearian

So I was working on a normal map base for a texture this morning, and I want to get an AO map out of it - but I have no idea if its possible with floating geometry (see below!).

So whats the best way to deal with this? or is something simple :P
Thanks for any help!

MoP

Well, you'll get an AO map, but it'll probably have some shadows around the edges of the floating geometry. You could either paint them out or ignore them.
For this type of thing you might be better off just using a Crazybump pass instead of "real" AO, or you could do something like Magic Wand select the "flat" area in the normal-map, and mask that out of your AO bake (since in this case that will get rid of any artifacts arising from the fact that these are floating).

arrangemonk

i would uvmap the highpoly, and render out an ao map without the floaters and then render out the aos for the floaters separately, and then bake the two like the normalmap to the lowpoly

fearian

hmm, If crazy bump gives me AO maps from normals I might finally get around to buying it!

I'll try merging the AO from the floaters and the base in photoshop as well though. Thanks for the help guys! I'll post results later today when I have some time to finish it.

Ghostscape

If you use a Max skylight and the scanline renderer, and render out a lighting map, rather than a mental ray AO map, you won't get shadow "halos" around the floaters, you'll just get shadows at intersections and in the 'bowls' of the floaters.

Mark Dygert

I seem to half remember that there was a trick for this besides CrazyBump which I also suggest trying.

You could try, rendering it two passes. One with the floaters hidden and another with only the floaters visible (or maybe it was with shadows on the floaters disabled?). Then composite the two passes? There might be something on the PC-Wiki about it...

arrangemonk

vig, thats exactly what i said

MoP

arrangemonk: No it's not, you said he should UV map the highpoly... which is really unnecessary. Vig doesn't ever suggest that.
You only need to do the two bakes from highpoly to lowpoly, and then composite in Photoshop. There is no need to UV map the highpoly at all.

That said, I find that process pretty fiddly and time-consuming especially with large and complex models, most of the time it's unnecessary IMHO.

Slum

You can render out an object ID pass that has different colors for floaters than solid geo. Use this in photoshop as a selection mask for your AO for cleanup.

This + mop's suggestion = win.

DEElekgolo

If you have vray then you can use Vray dirt.

fearian

MoP wrote: »

arrangemonk: No it's not, you said he should UV map the highpoly... which is really unnecessary. Vig doesn't ever suggest that.
You only need to do the two bakes from highpoly to lowpoly, and then composite in Photoshop. There is no need to UV map the highpoly at all.

That said, I find that process pretty fiddly and time-consuming especially with large and complex models, most of the time it's unnecessary IMHO.

I think its what he meant, if he mis-worded it. At least Vig's approach is what I got out of it.

So far Crazy bump seems to do the job fine, I'm having a crazy busy few days so I don't think I'll try anything else for now.

Eric Chadwick

http://wiki.polycount.net/Ambient_Occlusion_Map