When using rail sweep function how do you get the white center line to be the center of the carve project? I am trying to make a pine wood derby car similar to the blog posted on CW blogs, for my grandson, not real handy with the 3-D software yet. I have followed the blog instructions. Did the sketch of curve on one side of center then mirrored it to other side, but when hit ok the curve goes from one side to the other and does not have the sharp point in center of car. Probably something simple but has me stumped Thanks for the help in advance. Mike