machine design with 3D lines for Earthworks - error

Question

I made a machine design with 3D lines and exported it for Earthworks.
If I then select one of the 3D lines in Earthworks, I get the error message that no surface can be created for this line.
I have already copied the line, offset it 1cm parallel, changed the direction, checked double points - to no avail.
I work with TBC 5.51. Can anyone give me a hint?

Accepted Answer

That's a funny one, but I found it.
It's the leader line at the northern manhole. That has no elevation and isn't selected for output as 3D line, design map or site map. But it is exported.

In the simulator I could see for a split second before the error message pops up that it tries to compute the trench including the leader line, which shouldn't be there in the first place.
If you shorten that leader line, or delete it, it isn't exported anymore and it works.

I blame manly TBC here, that line isn't selected for export, but because the gap is so small it seems consider it as "connected" to the trench line.
And Earthworks also seems to ignore the small gap between the lines and tries to connect them.

Trimble Business Center

machine design with 3D lines for Earthworks - error