bool TrimExtendCurves( RebarTrimExtendData trimExtendData )
This function is called in the regeneration context when at least one data in trimExtendData parameter was changed. It is called immediately after GenerateCurves() and only if GenerateCurves() returns true.
If new constraints were created for start or end handle, a new regeneration will take place and the new constraints will become the rebar's actual constraints.
If new curves will be added by calling TrimExtendData.AddBarGeometry(), the existing curves in Rebar element will be replaced with these curves. It will not add curves to the existing ones.