Question: I want set an element's transformation point which is put on the stage.But I can't find the property in DisplayObject. Where is it ?

Thanks!

Answer: 
You have to define a transformation matrix for the displayObject. The transformation point is a property of the matrix, which can be set using transformPoint().

[See AS3 documentation for matrix.](http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/geom/Matrix.html)
Place your MovieClip on the scene, and select transformation tool (hotkey `Q`), you will see black squares for scaling object, and you will see white square. White square is a pivot for transformation, simply move it in any directions.