I am having a problem with ProjecttoCplane. I model boats and often need to project to the c-plane. When I do the command, it puts the new curve not on the actual c-plan but offset from it slightly, by about 5/32". It does not project ALL THE WAY to the plane. I have to make a centerline on 0,0,0 (cut plane) and use it to pull the chosen 3D curve to get it to lay down on the c-plane.
Correct I like to project to the c-plane to make sure everything is lying flat. In this file, I also just discover that a line is snapping to different places when I start it at 0…in 4-views I can start a line in the front view at 0, but in the right view it appears just above 0.