In the attached model I have used BlendSrf to join two parts, the larger of which is made from multiple surfaces joined (so I use the ChainEdges option). In the blend I get two areas of highly concentrated isocurves that appear to represent small ripples in the blend surface, as though it is made up of sections that are slightly misaligned. These originate where chained edges of the larger part meet. I believe that the joins in the larger part are clean so I don’t see an obvious reason for these discontinuities in the blend.
So is this a bug or known behaviour that wiser heads than mine can explain?
And what can I do to get rid of them (or better, avoid them)? I’ve tried trimming out the concentrations in the blend surface at the adjacent isocurves and blending the resulting edges but I’m still left with imperfections.
MergeSurfacesWrinkle.3dm (405.4 KB)
This is from Rhino 6 SR7