Extractions not unifying

Hi,

We are having re-occuring problems with a project not unifying extractions. It generally occurs after editing a linear form, but is pretty random as to when it actually becomes corrupt.

If you run the extraction using 2 Points & Direction or Distance and Orientation it fails to unify (also line weights are lost), but if extracting using a shape it can correct the problem. Having said that, we have used extractions using a shape getting increasingly larger to cover more of the model each time. This helped to locate particular elements that might be corrupt and cause the extraction not to unify. Re-modelling these specific elements can also fix the problem, but it does then come back when the models next get amended. There doesn't really seem to be a set pattern as to what is causing this problem. I also have a file where extracting using a shape over the full contents of the model works fine, but an extraction using Distance and Orientation doesn't...

I know of others that have also come across this problem, but have been unable to find a decent fix. The project in question does have curved slab edges and curved linear elements, this appears to be a common thing with others having the same problem.

Correct extraction using a shape:

 

Failed extraction using Distance and Orientation:

 

We are running AECOsim Building Designer V8i (SELECTseries 3) - Version 08.11.09.225, although I know people having similar problems on Bentley Structural V8i.

 

Has anyone got any suggestions?

 

Many Thanks,

Nick