The Transformations window is accessible via main menu > Transform > Transformations Window . It allows to do three types of operations on selected objects: 1. transformations, 2. alignment, 3. distribution. Buttons to switch between these three operation types are in the vertical tool box.
Rotation uses center (reference) point that can be moved in the work area with mouse cursor.
Note: if Apply Rotation to Fill Stitches option in the main menu > Transform > Flip & Rotate is checked, stitches angle is adjusted when object is rotated.
Alignment works with two or more selected objects.
Three objects selected in the Work Area.
Three horizontal controls align selected objects to left side, center and right side of the whole selection.
Three vertical controls align selected objects to top, center and bottom of the whole selection.
Objects from above example aligned to upper edge.
Distribution works with three or more selected objects.
Three vertical controls distribute objects in vertical direction so that tops, centers or bottom of objects are equally spaced within selection.
Three horizontal controls distribute objects in horizontal direction so that left sides, centers or right sides of objects are equally spaced within selection.
Remaining two controls distribute objects in vertical and horizontal directions so that there are equal spaces between objects.
Objects from above example equally spaced with respect to their centers.
Note: It is possible to combine multiple operations while Transformation window is open. For example, you can scale selected objects, align them according to upper edge and space them equally in the horizontal direction.