Sorting a List of 3d coplanar points to be clockwise or counterclockwise

Question

I have a list of 3D points. I know they are all coplanar. I have the center that I want to sort them around and the normal to the plane on which the points and the center li

Answer 1

There's no need to convert everything to 2D.

You have the center C and the normal n. To determine whether point B is clockwise or counterclockwise from point A, calculate dot(n, cross(A-C, B-C)). If the result is positive, B is counterclockwise from A; if it's negative, B is clockwise from A.