Hi NightCabbage,

> Ok, so that makes sense, but still, shouldn't I then be able to
> adjust the trimming edges?

Well, no - not to reshape the surface.

The trimming edges are things that are contained within the surface, marking which parts of the surface are active or inactive.

The trimming curves themselves do not define the shape of the surface geometry - the surface's control points are what do that.

This may give you a better idea of what I was describing earlier, about why you can't just pull any edge curve around to reshape a surface with NURBS - if it is a trim curve it is not defining the shape but instead marking active/inactive regions on the surface.

- Michael