Hi Michal,
Thanks for your suggestions, but these features doesn't suit well with RC , because the position of segments in RailClone is always dependent upon their position within the array, so it is always necessary to build the entire array to calculate the position of each segment correctly.
Said that, i must add that in V-Ray already exists some kind of camera clipping:
By default RailClone computes only the bounding box for all segments, and the final geometry is generated only when the raytracer hits that part of the RC object.
In fact, this method is more precise and efficient than Forest clipping, because has not problems with reflections, items near of the camera's bound, etc.
This feature can be enabled/disabled with a registry key (HKEY_LOCAL_MACHINE\SOFTWARE\Itoo Software\RailClone Pro\DynamicGeometry), and is enabled by default.