This question came in last week and had us scratching our heads a bit - turns out that there is a bug in TBC relating to conditional instructions and reference lines (in this case).
The issue is as follows
- The user had created a Corridor Model that had Reference Lines added to the model.
- They were using one of the Reference Lines in a conditional instruction and it was the first time that the reference line was used in the template.
- TBC currently does some checks on which nodes are defined but are not being used in the template and it ignores them in the calculations, they were not checking reference lines use in conditional instructions - so the lines are effectively being ignored from the creation of the corridor surface perspective.
The way to solve the problem is to use the reference line in an instruction prior to its use in the conditional instruction - just to create a dummy node - so I used an Offset Elevation instruction to create a point called Dummy at 0.01 offset and 0 elevation delta from the reference line node. I did not include that dummy node in a Material Layer. This causes the Corridor surface to create correctly thereby eliminating the problem.
The issue has been addressed for a future release of TBC - if you have this issue the symptoms showed up in the Template Editor was doing the right thing - the corridor model was correct, however the corridor surface model was not reflecting what the template editor was showing. Add the above fix and the surface output is fixed and you are good to go again.
In this case the conditional instruction is using the vertical distance between a node that gets created by the template and the node of the reference line, and if the distance is between 0 and 0.3 then create a set of instructions that form a ditch - the ditch showed up in the template but not in the surface model.
Video shows you how.
Hope this is useful
Alan