Plastic Window (Rigged) tutorial for

This is parametrically rigged model of PVC (plastic) window. What does it means? Model have MainControlDummy with Attribute Holder modifier on it. Window has 6 changeable parameters: Width, Height, Left and Right flaps opening horizontally and vertically. Z-position of Main Control Dummy - is the level of window bottom. Modeled in 3ds max 2014, rendered with Corona (alpha 6) and Corona materials.