Why is that when I build the clean surface without flags but when exported to TTM and then imported to another TBC then flags appears?
Could be one of several things Eric
1) The tolerance that you have set in Project Settings, Computation, Surface for Minimum Warning DIstance is set differently in the new project to the source project - and as a result a flag in one would not show up in the other
2) Could be that there are more than the maximum number of flags in your project (we only display like the first 200 flags and those are chosen in order of error magnitude), and if your flag is lower in error than the 200 displayed then it would not show up in the source project, but when it is the only data in the new project the Flags would show up
3) Could be that the surface has a very close to margin error and through export and reimport a number gets rounded and makes the error big enough to be shown as a flag
4) Could be also that Flags are turned off on the Surface (in Properties) in the Source Project, so you dont see them - but when you export and import into a new project they become visible
These are the reasons that I can think of quickly - there may be other reasons - if these are not the answer, send me the Project and the output file so I can test it and I can give you a more definitive answer
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