I am experimenting with 3D constraints. I have created an axle from two cylinders, with different diameters, and a cone for the transition. I want to create a DmDistance3d constraint between the circular edge at the top of what is now a conical transition, and the top face of the axle. Somehow this is not possible. The only way to achieve what I want is to introduce an additional 'helper' solid. See the attached file.
I don't like the 'helper' solid and wonder if there is another way to accomplish this.