3d curve

I think you can use UV scan method, or maybe even the grid method. I have lots of trouble understanding the UV method personally. Grid method you just click then drag a box over the surface you want to scan. Just select your cad features you want included, then just draw a box over the entire part. It won't include cad elements not selected.

Normal top down view of scan in first image to show how it is created. Picture 2 showing side profile to show scan following curve contour of part.

Perimeter scan is probably what you're after, can you provide an image of what you're trying to scan?

it could be due to the way you are creating the scan.  if it is a flat scan you are needing, then YOU need to do some typing after you click on the cad model.  You need to set the 'height' to all the same value and you need to check (and correct, if needed) the cut plane so that it is flat & square to the path you want, otherwise it will drift away from the model/part.

Its like the rim of a top hat... looking at it in the y mius workplane.... its all curvature. Used could do this with a 3d curve with Zeiss and then adjust the whole curves Z value... i need a closed scan that will follow the curve.. 

thanks for the help

What Ninjabadger suggested above will do, a perimeter scan, then if it isn't centered enough or positioned where you want, adjust your offset from the generated points