Bad object... but not sure where is the problem here?

Here is a closed polysurface [2 parts union-ed] and Rhino say it’s a bad object…
But it is closed.
My guess is that the edge tolerance was stretched during the union to exceeds the file tolerance

if so, is there then a way to check/find the location of the bad spots ?
it is not at the edges of the bottom side is checked that with extractSrf, would this be the way to find the problem by a process of elimination? or is there a better way?

*unfortunately I can’t publicly share the file.

with many thanks
akash

Hi Akash - use ExtractBadSrf to get at the bad surfaces in the object.

-Pascal

Hi Pascal
I overlooked/forgot that command.
some filets that were good before turned bad some how,
in the end the only fix that I found to work was to slice in half and mirror the good half.

thanks a lot
akash

Hi Akash - more often than not, extracting the surface, Untrimming it and then re-trimming with the surrounding surface edge curves, (or use DupBorder before untrimming and retrim with the curves) will fix things.

-Pascal