Defining odd Rotation Planes

addressing red, green or blue planes for rotation I succeed now thanks of this illustrative post (

Now what to do if the object to rotate is not in an orthogonal direction and is to rotate perpendiculary to the plane of this object which is not orthogonal either? Like the wings of a fly or a rotor blade of an helicopter…
Seems to be a little “academical”. The solution could teach a lot of SU strategies.

My workaround -not elegant at all- is to raise lines for orientation.


Here are a couple of ideas you can try after selecting the rotate tool:

If there is a Face whose normal vector points in the direction you want to rotate, you can press shift while hovering over that Face to lock the reference for rotation.

If there is an Edge you want to rotate around, if you click and then drag along the edge, the rotation will lock to that Edge.

The last resort is the one you mention: draw some helper geometry and then use either of the above to lock the rotation.

There are three ways to establish the axis of rotation of the Rotate tool.
It’s worth noting these same methods apply to the Protractor tool as well.

Allow the tool to auto-orient the axis of rotation about the drawing axes.

Allow the tool to auto-orient the axis of rotation to a face.

Methods 1 & 2 require just a single click to establish the axis of rotation. [Shift] locks the orientation.
Note the location and orientation of the Drawing Axes may be set any way you choose.

Establish the axis of rotation by hovering the Rotate tool over a meaningful point.
Then, press and hold (not click) then drag the cursor to hover over another meaningful point, then release.
You can rotate geometry about any axis at any point you choose by this method …regardless of the orientation of the Drawing Axes.

Tweaking Tool Tips — SketchUp Sage Site

Thank you pro your patience!
Must be frustrating to answer always the same well documented questions :wink:
Certainly the hint “press and drag along the edge and release” was opening a new field of ease.