Is there any way to lock sketch items to each other but not the sketch plane?

[GRSnyder]

I need to reproduce the profile of a real-world object. It's got some detail areas that I want to trace from a photograph and some larger rectilinear regions that are better measured with calipers. Here's an abstract version that shows the desired final result:

The elements in the circled area are the traced parts. They're traced at scale. I don't know or want to know the detailed dimensions or the many parameters needed to reproduce the spline curve. The other parts are dimensions that I want to enter and have the sketch adapt to. (Dimensions here show no values. This is a macOS Catalina issue; just assume these are normal dimensions with values entered by me.)

Ideally, I could group or lock the traced parts of the sketch so that they preserve their form relative to each other but are free to move about as a unit in response to changes in the dimensions. But this doesn't seem to be possible in Fusion 360 at the moment. Is there something I'm missing or is there just no way to achieve this effect?

I could fix the traced elements, but in addition to preserving their form, that locks them in place on the sketch canvas. I could also add lots of spurious dimensions to achieve the fixation, but this clutters up the sketch and obscures the fact that these dimensions are outputs of tracing rather than inputs to the sketch.

I also tried isolating the traced elements in a separate sketch and then projecting those elements into a composite sketch. It's possible to move the projected curves around with the Move/Copy command, but they cannot adapt to changes in dimensions. Nevertheless, this is the best workaround I've found so far. I just leave out the traced portion and complete the rest of the sketch as best I can, then move the traced region into place as a final step with a point-to-point move.

(Not really relevant, but I vaguely remember Inventor having a feature (symbols?) that served this function. I don't think this was the main goal of Inventor symbols, but it did seem to solve the problem.)

[jeff_strater · Accepted solution]

@GRSnyder - unfortunately, there is no easy way to do this today.  The only way to do that would be to fully dimension/constrain those lines/arcs/curves with respect to each other.  Then, that group would all move together.

The feature in Inventor I think you are thinking of is "sketch block", which does exactly this.  Fusion does not have sketch blocks today.

[etfrench]

Extrude the spline area as a separate component.  Do the same for the rest of the profile.  Use a joint to keep each component together. You should now be able to change dimensions without affecting the spline area. 

You could also experiment with a dimensioned control point spline.