I was wondering if it is possible to render an AO map in Max in a completely enclosed environment. The last couple projects I worked on were in Maya and it wasn’t an issue but Max doesn’t seem to like it. (I’m assuming it’s got to do with Max and not Mental Ray as I used Mental Ray in Maya.) Possibly Max has a default “light source” that it forces all instances of AO to use and since that light source is completely occluded in an enclosed environment the render turn out black…? Is this the case and is there a way around it?
Are you talking about just using a Skylight with Max’s Scanline renderer?
It’s true in that case, I think it just casts lots of rays from outside in, so if your scene is enclosed, it won’t get any light at all.
Fortunately Mental Ray still works fine for this in Max, you can just slap a dirtmap/ao map into the self-illumination slot of a material, apply that to all your objects, and render/bake.
Could you give an example of what you’re trying to render that’s enclosed? If it were the interior walls/ceiling/floor of a house for example, you could merely break the mesh up after unwrapping, render the maps, individually, and then compile them together in photoshop. Also, while it might give strange and undesired results, I had success with simple objects with selecting the mesh and flipping the faces (so all the walls would be facing outwards).
Trying multiple render setups with just skylights and then mental ray + shell shadowmaps, I could only get it to light it a flat color (even though details were present).
Edit:
MoP I tried that originally and I didn’t seem to have any luck… What kind of output are you using in render to texture? None seem to be working for me:?:.
Sorry, yeah, I forgot to mention you will need to tweak the mental ray settings for the dirtmap/ao thing, and bring the ray distance down until it looks right.
You don’t actually need any materials on the object at all if you don’t want. Just set the renderer to be Mental Ray and it exposes the Ambient Occlusion map type in the Render To Texture render elements. You don’t need any lights in the scene.
Select that and scroll down to the “selected element unique settings”. Whack up the samples (probably, my test looked garbage with less than 32). Change the Max distance to be a meaningful number (my scenes are in cms so a test room of a couple of metres needed a max spread of 100units (1 metre).
Should be good to go. Fiddle with the other settings if you want.
It turns out I had to turn the Max Dis up to over 100 to start getting any non-occlusion happening…At lower then 100 the render was just straight white on all the interior walls. I had fiddled with it between .1 and 100 and didn’t see any much difference so assumed it wasn’t working. However, since I’m just doing tests I wasn’t paying attention to my scale which was very large so the Max Dis needed to be large as well in order to sample inside the object.
I feel kinda like a moron because if i recall it was the same setting in Maya you had to use in interior scenes but I never had to turn it above 20…