[quote user="John Drsek"]How to tell if your cursor is to the left or right of a point?[/quote]
I've written a VBA project that shows how to do that...
The macro works in dynamics. Start by identifying a cell. Move the cursor, and it draws the yellow line from the cell origin to the cursor location. At the same time, it draws the green line 'north' from the cell origin. 'North' depends on the view rotation. As you move the cursor, it informs you whether you are left or right of 'north'.
The macro makes use of VBA linear algebra objects: Vector3d, Matrix3d and operations on those data. It avoids trigonometry entirely, leading to a concise implementation..