# Object Rotation Direction vs Compass / Cardinal Directions

Is it just me or does it seem counterintuitive that Object Rotation Directions are reversed vs Compass / Cardinal Directions? Is there some logic to this that I’m missing?
Best, Bill

Yes, mathematical logic… In a mathematical right handed Cartesian coordinate system, 0 degrees is along the positive X axis, and positive rotation is counter clockwise… Since construction of 3d geometry is based on this kind of mathematics, it is logical that Rhino should use it…

–Mitch

Rotation is based on the unit circle where 0 degrees is at ‘3 o’clock’ or the X axis, and pi/2 or 90 at ‘12 o’clock’, or the Y axis, etc. That is, ‘+’ is counter clockwise if the axis is pointing towards you.

-Pascal

Ahhh Yes, I have vague recollections of this from 8th grade geometry!
It also slipped my pea brain that Cartesian Coordinate System was invented by Descarte.
Here is the relevant Wiki that I used to RTFM: http://en.wikipedia.org/wiki/Cartesian_coordinate_system
Thanks for the clear & concise explanation Mitch & Pascal

Best, Bill

You, of course, meant to say "…’+’ is counter clockwise if the Z axis is pointed toward you. We all knew that.

Hmm- well, I should have specified ‘rotation axis’- is that more like it?

-Pascal

It’s a right PITA for us sailors who have to re-boot our brains every time we get back on the boat after being in CAD land.
But, you get used to it

Just like sea-legs, right?

-Pascal