Extract an ambient occlusion map

You can extract an ambient occlusion map using different subdivision levels of the same mesh as the source and target mesh, or extract a map between multiple arbitrary objects, even if the source meshes have no UVs. See also Ambient occlusion maps overview.

When extracting an ambient occlusion map from a single object, you can select the same target and source models. If you have only one mesh in the scene, the object will automatically load in the Source Models and Target Models lists when you open the Extract Texture Maps window.

ImportantOnly visible meshes act as occluders in the ambient occlusion map extraction. Before extracting the map, ensure all objects you want to occlude light are visible. Hide any objects that you do not want to darken the target object.

To extract an ambient occlusion map

Select Maps > Extract Texture Maps > New Operation.
Select Ambient Occlusion Map in the Maps to Generate section.
The Extract Texture Maps window updates to display all Ambient Occlusion Map Extraction options.
Select your target model(s) in the 3D View, then click Add Selected in the Target Models section of the Extract Texture Maps window.
Note
Unless you are extracting the ambient occlusion map in Ptex format, the target model(s) must have UV co-ordinates.
Add the high resolution (source) model(s) you want to the Source Models list, ensuring that the subdivision level you want to use to produce the map is selected.
Selecting the source model at the highest subdivision level provides the highest detailed ambient occlusion maps possible. You can extract an ambient occlusion map at lower subdivision levels, but fine detail will be lost and the appearance of facets may result because of the reduced resolution.
In the Output Options, set the Map Type you want to extract: Texture (image file) or Ptex.
The other options available in the Extract Texture Maps window update dynamically depending on which type of file you want to extract.
Do either of the following, depending on which Map Type (Ptex or Texture) you selected:
- For texture maps, specify the Image properties for output.
  The Image Size determines the resolution of the image map and the amount of surface sampling that occurs between the source and target models.
- For Ptex, use the Ptex resolution options.

TipThe first time you extract an ambient occlusion texture map, set the Quality setting to Fastest and Image Size to a small resolution to quickly generate a test map. Evaluate this initial test, adjust any settings as required, and then set the Quality and Image Size options to the final settings before generating a final map.

Set the other Output options you want.
- For texture maps, click the browse icon beside Base File Name and enter a file name in the Save As window that appears.
  This name is used as a prefix for the file name of each output texture.
  
  In the Save As window, you can also select an appropriate file format from the Save as type drop-down menu, and click Save.
- For Ptex, click the browse icon beside File Name to set the save options, and select the Data Format you want.
Set the other extraction properties as required.
For example, to automatically bake a texture to the target model(s) as a diffuse paint layer (on top of any existing paint layers in the Diffuse channel), click next to Base File Name to select an image format in the Save As window), and turn on the Preview as Diffuse option.

For descriptions of Shadow Map Resolution, Shadow Darkness, Shadow Contrast, and Filter see Ambient Occlusion Map Extraction options.
Click Extract.

A progress bar displays on the Status Line as Mudbox calculates and composites the shadow maps. If you have multiple target objects, the progress bar may repeat the process several times.

NoteUnless you are extracting the ambient occlusion map in Ptex format, the target model must have UV co-ordinates. Otherwise, the following message appears when you click Extract: The model mesh has no UVs. Mudbox needs UVs to generate Ambient Occlusion Maps. Try selecting Recreate Level UVs under the Mesh menu. For more information, see UVs overview.

If the model contains UVs within multiple UV tile spaces, that is, outside the 0 to 1 range, Mudbox automatically creates separate ambient occlusion maps that correlate to each UV tile and saves them to the directory you specify.

NoteIf your model contains multiple UV tiles, each tile appears in a different color after the ambient occlusion map is applied to indicate that the textures are currently unloaded. This is a graphics memory optimization feature. For more information, see Hide and show texture tiles on a model.

Edit an ambient occlusion map

If you create your ambient occlusion map as an image file and apply it as a visible Diffuse paint layer, you can evaluate it and make successive iterations, changing the extraction settings, then extracting and previewing again.

If you extract successive ambient occlusion maps using the same file name, you overwrite the previous map, and the paint layer is automatically updated in the 3D View.

You can use the Paint tools to modify or enhance the ambient occlusion map (add shading, erase shading, and so on) when the map is applied as a Diffuse paint layer. For more information, see Painting.