Navigation:  Menus > Transform Menu > Mark Center

Selection prerequisites: Any number of objects including at least one point

This Transform menu command marks the most recently selected point as the center point about which future rotations and dilations will take place.

If you haven’t yet marked a center when you choose Rotate or Dilate, Sketchpad will automatically choose a point and mark it for you.

The keyboard shortcut for Mark Center is Shift+Ctrl+F (Windows) or Shift-F (Mac).

To mark a center:

•Select a point and choose Transform | Mark Center, or

•Double-click a point with the Selection Arrow tool.

The marked point will flash briefly to indicate it’s been marked as the center for future rotations and dilations. Once marked, this center point will be used for all future rotations and dilations until you mark a different center point.

You can also mark a center after choosing Rotate or Dilate. With the dialog box open, click the desired center point in your sketch.