In a Sketch, I know that if you dimension to a construction line to a solid line, you can "double dim" it by pulling the dimension across the construction line - thereby creating a diameter dimension for a revolved feature.

I'm modeling a belt sheave and I want to set the thickness of the grooves relative to the belt thickness and a distance from the center of the pulley. I do this by creating all the groove geometry, then placing a construction line between the slanted walls of the groove, setting it's thickness to the top width of the belt, and then setting the distance to the center... but SWX will only let me give a straight line to line, it won't "double dim" the dimension, giving me the diameter.

I know that simple math will accomplish the same goal (and I've defaulted to that) but it doesn't mesh with the design intent of the model. This seems elementary to me...

Basically, I can't seem to make this work between two construction lines.... is this possible? or is this a case where our CAD manager's procrastination in upgrading (despite subscription service and prodding from the designers) from SWX2008 has me dealing with issues that have been solved in a new release?