As a model builder for furniture I often want to make full parametric models with curves and the such like, this is nearly impossible in Revit.
Mostly I create a reference line and then create a sweep picking those lines as they are about the most predictable geometry feature when it comes to curves.
I notice many modelers simply create multiple size families and nest them making the appropriate one visible with parameters, this seems to me to not only be inefficient but also adds a load of dead weight to a project.
Being able to constrain model lines (and reference lines/planes) with tangent, parallel, concentric and similar constrints, and also being able to add a dimension between two concentric lines (without having to create a parameter, formula and two radius dimensions) would be a very valuable addition.
