# MACRO Challenge: Cut curve in the middle, Mirror it with Symmetry and History

Modeling vehicles requires symmetry in curvature. Complex shapes require MANY curves across the width of the vehicle that must be symmetrical.
Designers like me, that cannot sketch, need to noodle full width curves into shape for hours to get the sense of it and then make it perfectly symmetrical.
Noodling requires the full width curve even if it is not perfectly symmetrical to eyeball it properly. Sometimes a surface must be created to see how it spans from the curve.
When this is all finished, I cut the curve in the middle by creting a short line snapping to he curve somewhere hear the middle, then trim away half.
Then the problems begin. The end point must be exactly on the midline. I can grab the point and pull it to snap on the grid in an isometric view, but it will jump to the zero line in the other isometric view. I cannot use the gumball to snap to a grid by pulling on one arrow (unless I missed something) so a lengthy process begins to get it close but just to one side of the midline.
Next I turn on history and create a mirror image using SYMMETRY. This appears to join the two lines at the midsection and ensure continuity at the midline,
Finally, if needed I noodle a control point or two.

I find myself doing this a lot more often than I would like. Is there some clever way to do this with the push of an F key - looking at you Pascal ))

Try using SetPt to place the control point at the end of the curve at the desired x, y or z value. Or you could use Align.

Hi @Proterio
A couple of things that might help: If you call `Symmetry` on a curve, it will automatically pull the end point to the center axis, if the continuity is set to `Smooth`. If you want to use the gumball, you can select your end point, start dragging the appropriate axis handle and then type 0 followed by Enter on the keyboard to move it to the world center line, moving it only in the direction (X, Y or Z) of the handle - this requires “Snappy Dragging” to be on in the gumball settings.
HTH, Jakob

Aaaah yes I suspected Symmetry snapped to mid point. Thx for confirming that
Snappy dragging… must find that

I also forgot to mention that the direction of the curve MUST BE toward the center. I often have to flip the curve before doing the symmetry.
All these details and requirements and steps are VERY distracting and by the time I have completed one curve, I forgot what I was going to do next and what Ideas I wanted to try out.

Left click the Menu ball (that’s the little white circle that’s offset from the center of the Gumball) and select Snappy Dragging instead of Smooth Dragging - about 2 thirds down the list
-Jakob