@jandyman wrote:
... I'm always happy to learn more techniques ...
Before I show techniques, I feel the need to explain concepts:
First, CAD software uses two main sets of mathematical descriptions to represent geometry.
- Analytical geometry: spheres, tori, planes, boxes, prisms, pyramids, etc., and sections of such geometry.
- NURBS for arbitrarily curved surfaces.
In the case of a solid body, those are stitched into a BRep.
Analytical geometry is mathematically much simpler than NURBS! That includes calculating self-intersections.
Filleting lines and arcs with circular or constant radius fillets creates analytical geometry. In essence, cylinders or sections of tori. A variable radius fillet with 2 different radii along a straight edge can still be represented as a section
of a cone, so "simple" analytical geometry.
However, once you add a third radius somewhere in between, the resulting surface will be represented by NURBS.
When you use Splines (NURBS) to create the outline of your instrument, and then fillet those, that creates a very complex surface. Sometimes, the geometric modeling kernel of Fusion can deal with self-intersections of such surfaces, but more often than not, it cannot.
Ultimately, to create the "sculpted" or "organic" or "freeform" shapes of your instruments, you will need to move so surface modeling and , yes, that includes lofts 😉
