UGRID File Format
 

I am debugging a UGRID file from an external source that is rejected by my code during import because it is using zero and negative face_id values.

Comments in my UGRID import/export code suggest that patch face_ids must be >= 1 (non-zero, positive).

I have a comment in my code referencing this MS State Sim Center UGRID format spec. Unfortunately, that link is now broken. :(

So far, I have not been able to find any other UGRID format spec docs on the "interwebs".

Can someone direct me to a UGRID file format spec?

or

Can someone provide details on the allowed range for face_id values?

thanks!