+ # @param scaleFactors optional scale factors to apply during extrusion
+ # @param linearVariation if @c True, scaleFactors are spread over all @a scaleFactors,
+ # else scaleFactors[i] is applied to nodes at the i-th extrusion step
+ # @param basePoint optional scaling center; if not provided, a gravity center of
+ # nodes and elements being extruded is used as the scaling center.
+ # It can be either
+ # - a list of tree components of the point or
+ # - a node ID or
+ # - a GEOM point