3D Graphics Programming with QuickDraw 3D 1.5.4

Transparency

Transparency is the ability of an object to transmit light, possibly permitting a viewer to see objects behind it. The interactive renderer allows you to draw objects with varying degrees of transparency. You specify how much light can pass through an object by setting its transparency color. A transparency color is an attribute of type TQ3ColorRGB , where the value (0, 0, 0) indicates complete transparency, and (1, 1, 1) indicates complete opacity. By default, objects are rendered opaque.

You specify an object's transparency color by adding an attribute of type kQ3AttributeTypeTransparencyColor to the object's attribute set. QuickDraw 3D multiplies that transparency color by the object's diffuse color whenever a transparency color attribute is attached to the object.