The StartDistance property of the GradientFogController class specifies the distance from the camera at which the fog effect begins. This property is a float value representing the starting point of the fog in world units.

To use the StartDistance property, you need to have an instance of the GradientFogController class. You can then get or set the StartDistance to control where the fog effect starts relative to the camera.

Example usage:

GradientFogController fogController = new GradientFogController();
fogController.StartDistance = 50.0f; // Sets the fog to start 50 units away from the camera