Despite colinearity of the curve at both points of contact, I am left with a naked edge after trimming. However, the naked edge is not an issue, when I build surface 4. When matching its short edge to surface 1, however, the naked edge not surprisingly raises its ugly head again.
In Alias, one would build surface 4 to the short curve, without trimming surface 1, and then simply “align project normal/vector”, which pulls the surface edge onto surface 1 with a G2 alignment, and at the same time creates the correct trimming curve. Match does not have these options, so what is the “Rhino way” to get the trimming/matching right?
I think I figured it out how to do this in Rhino. One should not match surface edges and curves when collinearity occurs, but rather use only curves and trim surface 1 at once, not in steps. Still, it is odd that there’s a visible gap, but the value is 0.004, while supposedly larger gaps do not show. The model joins anyway and successfully opens in Creo.
Also, in Rhino one has to match the simpler opposing sides (Match target isocurve direction), and only then the short trimmed edge with far more curvature (Match edges by closest points & Preserve isocurve direction), and then again match the opposing sides, because matching to the short trimmed edge wrecks G2 on the previously matched edges. So, it’s a bit of matching ping-pong.
