Press R : begin rotation about the rotation point (center of data or 2D cursor)
Hold Ctrl : reduce angle applied by mouse movements by 10X.
Left click : confirm
Right click : cancel. Return selected to original positions
Use Meshmixer's rotation wheel. Collect common angles and visualize them on the wheel (an answer to "smart guides")
Press R : begin rotation about the rotation point (center of data or 2D cursor) Hold Ctrl : reduce angle applied by mouse movements by 10X. Left click : confirm Right click : cancel. Return selected to original positions
Use Meshmixer's rotation wheel. Collect common angles and visualize them on the wheel (an answer to "smart guides")