As we have seen up to now, the right mouse button selects objects, and the left mouse button starts creation of some object. The middle mouse button is used to move objects, and the combinations of Shift and Ctrl with the left and middle mouse button access the scale, stretch and rotate functions as follows:
Left Mouse Middle Mouse
Plain (start drawing) move Shift scale pan Ctrl stretch rotate
By default, the rotate function rotates around the center of the bounding box for the selected object. This behavior can be overridden by specifying a coordinate system with the ` key, see Directional snapping. If a coordinate system is set, then the origin is used as the center of rotation.
The scale and stretch function use a corner of the bounding box of the primary selection as the fix-point of the transformation. Again, if a coordinate system is set, the origin of the system is used instead.
It is often convenient to rotate or scale around a vertex of an object. This is easy to achieve by setting the origin of the coordinate system to that vertex, using the snap to vertex function for setting the coordinate system.