Done!
(Oh and sorry for the big images, but this thread was already stretched so it shouldn't make much of a difference)
1. SETTING UP THE SHADER NETWORK
-Open up the model that you want to render AO maps on, I'll just choose this ear here.
-Now you need to dwelve into the jungle that is the hypershade, which is an incredibly in-depth tool of maya's, but for our purposes you really don't need to know anything about it. To do this go to "Window > Rendering Editors > Hypershade".
-This should now have opened the hypershade in a separate window, first what you need to make sure of is to activate "Create all nodes" in the upper left corner if not already on. After you've done this you'll need to create the actual material node that we will be using to connect the ambient occlusion texture into. So simply click the little button that says "Surface shader".
-What you will now notice is that this created a small box in the lower portion of the hypershade with the icon of the previous created material. This is the material node. Now what we need to do is assign the ambient occlusion texture to this node. So on the left bar of the hypershade scroll down a bit until you find the "Textures" category. Unfold this.
-Now you will see other texture "nodes" in this category similar to where the surface shader was previously. What you will now need to choose is the "mib_fast_occlusion" .
-After you've chosen it double click the box that it created, this will open up the attributes of this texture in the attribute editor. This may be opened in the actual maya window or in a separate window depending on what settings you have set. You will most likely see these default settings.
-We will need to change a few things in here, first, change the samples to something like 256, basically, the higher the samples are, the smoother the AO will be. So we want this pretty high. I also tend to change the dark/lights of the AO a little bit just to make the render a bit easier on the eyes. Try to render both with these at default and at a little bit reduced and choose what you prefer yourself.
-Now go back into the hypershade and (If you haven't already) grab the mib_fast_occlusion box in the lower portion of the window and move it to the right a little bit just so that you can see both the surface shader and the AO texture at the same time. Now grab the AO box with the middle mouse button and drag it on top of the surface shader and let go of the middle mouse button. This will bring up a little menu which asks you to what attributes you want to connect the texture to. And for our purposes you just need to choose the "default" option.
-Now comes actually assigning the material to the model, this is pretty straight forward. Simply first select the object/objects that you want the material assigned to, then move over into the hypershade and right-click on the surface shader (Don't select it first, as this will deselect the model) and chose "Assign material to selection". If you've done this correctly your model should now look completely black. Don't worry, that's just the surface shader, once we render it it'll look way better.
-Before we render it we will need to fix a few simple rendering settings. So first go to "Window > Rendering Editors > Render Settings" this will pop up another window where you can chose from a lot of different rendering settings.
-Now, the render settings window will look different in different versions of Maya so I won't actually go in-depth on how it's laid out but you will want to render using mental ray and set the quality preset to "Production".
-Now we basically just want to render it out.
2. BAKING THE AO MAP.
-Baking it is extremely simple really, first of all you will need to change to the rendering menuset. Do this by choosing "Rendering" from the drop-down box in the upper left of the maya window.
-Now go to "Lightning/Shading > Batch Bake (mental ray) > option box.
-These are the settings I got a long time ago from some tutorial and have been using ever since, works perfect for me so it should for you as well. When you have set the settings correctly you'll need to press "Convert and Close" at the bottom of the window. This will start baking the map, now, because we bake it with 256 samples on to a 1024 map this might take a while considering your computer speed. For me it took about 10 minutes, and it'll seem to have frozen but it hasn't it simply is working.
-The image will be baked into your project directory>Your current project's name>renderData>mentalray>lightMap and boom you have a AO map.
Very simple once you get the hang of it.
Alucard94, the member of the future of the past.
