# Composed Transformation

A powerful feature of a CogTransform2DLinear 2D linear transformations is that the composition of any number of CogTransform2DLinear objects can be represented by a single CogTransform2DLinear object. The result of composing a CogTransform2DPerspectiveAndRadial transformation with any other type of VisionPro transformation object, however, cannot be represented as a new CogTransform2DPerspectiveAndRadial object.

Because the composition of transformations is such a commonly used and powerful feature, VisionPro implements a special transformation object, CogTransform2DComposed, that lets you create a single object that can represent the composition of any number of VisionPro transformation objects, regardless of their types. This object lets you combine radial and perspective transformation information with other transformations into a single object which you can then use to map points.

Note: The ComposeBase function automatically returns a composed transformation object when it is called upon to compose two transformations whose composition cannot be represented by a transformation object other than a CogTransform2DComposed.