If I have a 3D surface in AutoCAD, I can apply a UCS to any point on the surface by selecting it, and it automatically creates the UCS with the Z-axis as normal to the surface. This is perfect.
The issue that I am having, is that I am going to be programming a LISP to apply many small features (100k) that each must be normal to the surface at the individual point, and the surface is constantly changing. When I try using point inputs (via keyboard in manual trials), I am unable to easily place a UCS that is normal to the surface. If I put a point on the surface, and float over with my mouse, it finds the point and the surface and places is properly as well. It will also work with a line on the surface, finding a "nearest" with the mouse and applying the UCS properly to the surface.
The main thing is that I need to automate this, so that it does not require user input. If there is another way to find the normal to a conformal surface at a point in autocad, I assume I would also be able to get that to work.