how can I point3dcollection converter to acgepoint3dArray and DoubleCollection converter to acgedoubleArray
Why would you want to do that? Virtually any ObjectARX function that takes a AcGePoint3dArray or a AcGeDoubleArray has a managed wrapper that you can call directly with a Point3DCollection or a DoubleCollection respectively.
Besides, there are no conversions involved: AcGePoint3dArray for example is what is unsafely pointed at by the UnmanagedObject property of an instance of a Point3DCollection.
