I am trying to figure out how to determine the location of points from each other using either a UV system or a coordinate system. the problem seems to be that I dont have no way of knowing the orign (0,0) of a surface that I create with any regularity? is it supposed to be at its origin? If i create a rectangular surface for example, and have 4 points on it. How do I determine what is X and what is Y, U or V? or even how do I determine where the origin UV=0,0? See below.
So I thought about using coordinate systems, bu the problem with those seems to be that I need to make all of the axes align along lines, but I dont know how that would be possible. If I use the coordiante system by plane that seems to work good in that the red axis (which I am assuming is Z? always seems to point straight up. But is that the way it is in all cases? However, the Blue axis seems to be normal to the line which is good but sometimes it is reversed on the same line. The green axis, siimilarly is sometimes reversed. Is there a way to get them all aligned and pointing the same way? Can I somehow use a vector along the polycurves, and the XY plane to straighten them out somehow?