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The renderer uses the RixProjectionFactory object by invoking RixBxdfFactory::CreateProjection()  to obtain a  RixProjection. A description of various options associated with the current render are provided to the factory via the RixProjectionEnvironment &env. This class includes information about the current format (the width and height of the image in pixels and the pixel aspect ratio), the screen window, the shutter time values, the near and far clipping planes, and the world to camera transform. Developers are expected to use this information, along with the arguments supplied to the plugin via the RixParameterList pList pList, to create an instance of RixProjection that encapsulates the information necessary to model the desired camera and lens behavior.

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