Thanks! Your macro did the job perfectly!
Let me explain the issue with using default tolerance setting for trim/split. The attached file below (which I also had in the other thread from the link in my last post above) consists a surface and a curve. If you try to split or trim the upper left corner of surface with the curve while at the default absolute tolerance of 0,01 mm, the trim/split will fail, because Rhino ignores the fact that the curve intersects with the surface by 0,008268 mm. However, if I temporarily set the absolute tolerance to 0,0001 mm (or if I run your custom macro), the split/trim works as expected and the resulting split surface is accurate.
Tolerance test.3dm (158.7 KB)
This is why I proposed to add an optional separate setting for the “Trim”, “Split” and “Project” commands in the Rhino options panel, which allows the user to set a finer tolerance just for these 3 specific commands, while the rest Rhino commands stick to the absolute tolerance.
I can’t try Rhino 7 WIP since it’s not available for users of Evaluation Rhino 6, but on your screen-shot I see one improvement in “Blend surface” that I pointed out recently - the inability of the end handles to align to the same direction as the edges of the target surface. It’s even shown on my screen-shot in my post above where the split surface caused irregular flow of the blend surface as the latter tried to be perpendicular to the split edge. Is it really possible to align the handles in Rhino 7? That would be a huge benefit in many situations. Recently I also faced similar case while I created a blend surface between two surfaces created by the people behind the XNurbs plug-in. Their 3d model was posted in another thread as an example where they claimed XNurbs achieves better result than any other Rhino tools. Then I proved that several Rhino tools achieve considerably better result than XNurbs in that particular example, but in order to align the sides of the blend surface I had to use some tricks such like “Match surface” with the “Match target isocurve direction”, as well as two blend curves as a guide for the blend surface. The other workaround was by using “Sweep 2 rails” instead of “Blend surface”. I wonder how Rhino 7’s “Blend surface” will behave there. Rhino 6’s “Blend surface” showed quite messy result while G1 or G2 is used. However, if G0 is used, followed by “Rebuild surface UV” and then “Match surface”, it works properly. This is the file:
Rhino tools are superior in this scenario.3dm (1.4 MB)
P.S.: Alias has refit setting for blend surface and match surface for years, so I’m happy to see that this very important option is being implemented in Rhino 7!