OptionalexposureOptionalfilePath to the environment file in sources. If the value is null, the first found environment file will be used.
OptionalpreserveA scene may contain 3D lights, like area lights or spot lights. By default, all those lights are removed when a new environment is set. Set this option to true to preserve the scene 3D lights.
OptionalrotationControls the orientation of the environment map.
Exposure, in EV (0=neutral).