Bug? Cap not closing

In the attached I have an open polysrf created a a loft from 3 closed, planar, polycrvs, leaving planar openings at the top and bottom.

CAP creates a surface at each of the openings but does not create a closed polysrf.


  1. DupBorder, planarsrf, join all; or
  2. Planarsrf at each end, join all

creates a closed polysrf.

Maybe there is some underlying weirdness I am not seeing.

Problem Cap.3dm.zip (84.7 KB)

Hello- only two curves are in the file, but if you SimplifyCrv then loft, the result is cleaner, and closes.