With Mudbox 2009 SP1 has the ability to bake AO maps. This is a great improvement in Mudbox and can help tremendously when you start with either painting your mesh in Mudbox or even enhancing your render when used with another 3D application such as Maya or MAX.
When you first start the extraction process under Maps >  Extract Ambient Occlusion Maps > New Operation,  you will be greeted with this window.

 The first part of the Extract Window is the most common and easiest part to use.
 

Quality:  is the amount of rays gets generated to calculate the AO map.
Here is a comparison of the Quality setting between the Fastest and Best

For the sake of the comparison, I compiled the following images with the extraction time.

Note:   The only variable changed is “Quality” and the approximate time used to generate the AO map.
Fastest = 2 seconds
Fast = 4 seconds
Normal = 9 seconds
Good = 16 seconds
Best = 26 seconds

Image Size:  How big you want the image to be, my recommendation is to have it the same size as your painting layers if you have any.

Base File Name:  The default file extension is “png” but it can also support:  bmp, jpg, gif and tga.
NOTE:  These are all 8 bit files not 32 bit files. 
For most users that is what you need to know regarding the AO extraction.

The ‘Advanced’ Options
Shadow Map Resolution:  Based on the size of the shadow map, you will get the dark areas of the AO map since it limits the amount of pixels that is captured in the dark areas.

In my tests, I didn’t notice any significant change in extraction time when changing the size of the shadow map. 
The extraction time relies heavily on the “Quality” option.

Add as a Paint Layer:  With this option on, the extracted AO file will be added as a diffused paint layer.  NOTE:  At the moment, there are no blending options in Mudbox.

Shadow Darkness: This is the amount of dark areas in the occlusion map. The default value is 0.5.

Shadow Contrast:  Controls the contrast between the dark and light areas.  The default value is 0.

Filter:  The same principle when adding a filter in Photoshop or any image manipulation application.
The default value in 0.01.

Note: the smaller the value is (without going to the 0 ) will create a more distinct map
Bleed Width:  This is the amount of pixels that gets calculated further away from the start point.

Skip Back Light:  The default option is to leave the back light ON.   This will allow the back side of the object that the camera doesn’t view to be baked with the same manner the front part does, this way you get a more  uniform AO bake regardless of the camera position.

Note : Mesh resolution
the baking process is based on the mesh resolution, thus the higher the mesh the better the bake would be

 After the bake process is complete, a new paint ‘Diffuse’ layer will be added with the newly baked texture file.

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This entry was posted on Wednesday, March 25th, 2009 at 3:28 pm and is filed under Mudbox. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.