What does this error message mean ?

[dwc]

MISSING_SPAN_INFO: span info missing for ef_int construction
What does this error message mean ? And what can I do to eliminate it?
This is showing up after I loft a feature and then try to mirror it.
The loft does not show an error, the error message is the mirror status.
I have done very similar features to this one many times without any problems.
I have reduced my part to the minimum and attached the package (using V21).
Thanks in advance for any ideas.
Don

 

[DavidJ]

Try adding colinear constraint between the straight line and the X axis in Sketch 2

 

[dwc]

YES!
Thanks David, spent too much time looking at it and missed that the horizontal constraint is, of course, not colinear.
Don

 

[DavidJ]

Yeah, lofts tend to either work straight away or can take forever to diagnose. The fact the line wasn't fully constrained jumped out, and it's known that the ACIS kernel doesn't play well with thin slivers. Luckily the first thing I tried worked - which often isn't the case.

 

[GIOV]

Excellent advise.
Congrats DavidJ.