returns mutable Viewer from V3d
---Purpose: Create a Viewer on the given device with the given parameters or
-- with their default values.
+ -- Currently creating of more than 100 viewer instances
+ -- is not supported and leads to an exception.
+ -- This limitation might be addressed in some future OCCT releases.
raises BadValue from Viewer ;
---Purpose: If the size of the view is <= 0
-- if ComputedMode is false, only the degenerate mode will be used.