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.
Select your source mesh in the 3D View, then click Add Selected in the Source Models area. (To use multiple source meshes, click Add All, then remove any mesh you don’t want to use.)
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.
Set the other extraction properties as required. For example:
- To automatically bake the 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.
- To extract a Ptex file, select the Ptex format in the Save As window.
For descriptions of Shadow Map Resolution, Shadow Darkness, Shadow Contrast, and Filter see Ambient Occlusion Map Extraction options.
Click Extract.
TipThe first time you extract an ambient occlusion 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.

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 UV 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.