Allows you to select a bitmap file or procedural map for the ambient map type.
The ambient map is not usually used as a separate map type. It maps an image to the ambient color of the material. The picture in the bitmap is painted on the shaded parts of the object.
By default, the diffuse map automatically maps the ambient component as well, because you seldom use a different map for diffuse and ambient components. If you do want to apply a separate ambient map, click the lock button to the right of the long buttons. This unlocks the ambient and diffuse maps. You can then click the Ambient button to select a file.