I know the issue of having an associative copy for curves and surfaces has come up before, but as someone who does almost exclusively free-form surface modeling, I would like to see a rush put on this.

I work mostly on aircraft models which are symmetric, so I generally create half of the aircraft and then mirror those surfaces to create the other half. Aside from the issue of the mirrored half not updating with the original, a major problem is that the mirrored surfaces are explicitly defined NURBS surfaces. For complex surfaces such as fuselages, the mirrored surfaces can have hundreds of control points, driving up the file size. With one model, the full airplane was 32 MB, but when I deleted the mirrored surfaces it dropped to 4 MB.

Another issue is that a similar thing happens when trimming surfaces. A lot, if not most, of the time the trimmed surface loses its associativity with the trimming object and is changed into an NURBS surfaces with lots of control points.

With these two issues, it is very easy to get a model with relatively few surfaces up to 150 MB or more. Having a way of defining mirrored surfaces and trimmed surfaces without having so many control points would GREATLY reduce file sizes and improve the usability of the software.

Yes Please !