Hi ed, a way that may be potentially easier but doesn't give you the exact same result is to do an extrusion of your pattern instead of making a tube out of it, then flow the extruded piece onto your ring, then fillet the final result to produce some rounding.

I've attached an example of that kind of process.


The tubular method is going to be problematic currently because you can't just make a long tube that criss-crosses over itself and then use that directly as a cutting object - the cutting object for a boolean can't intersect itself so that base piece needs quite a bit of work on it to clean it up before it would be ready to use as a cutter. You'd need to build it in several sections that can be intersected with one another and like you mentioned before, you probably need to have the pieces hit each other with slightly different radius values where they cross each other since the surface/surface intersector in the geometry library that MoI uses has problems with that particular case of dealing with 2 tubes of the exact same radius that cross each other.

I'll try to think about how that crossing tube problem can be improved.

- Michael