Although you can’t see it, there is a tiny extra edge at the top where the surfaces are joined. I’m not sure why Check doesn’t report it, As Pascal suggests, retrimming fixes the problem. It would be great to know how the edge got there. I can’t recreate the problem using sweep. Can you remake this and get the same problem? If so, please let us know exactly how to do it.
There is a new test command called testRemoveAllNakedMicroLoops in the sr8 release candidate. It may have made it into sr7, I don’t have a copy of sr7t handy to check… You can also fix you model by calling that. Since it is a test command, you have to type it out completely.
Chuck Welsh
Robert McNeel and Associates