These questions come up all the time - but worth capturing the troubleshooting approach so that you see what we look for when things don’t appear to be working right.
In this example the user has a centerline, some edge of pavement lines, a flow line, a curb line etc. and they add the lines to a vertical design but then the first -2% cross slope rule fails and they cannot get any further - so why does that happen?
The issue traces back to how the Cross Slope rule works and how it is defined. The cross slope rule applies to the entire length of the target line, so if the target line happens to be longer (in projected offset from the source line (draw a perpendicular from source to target at the start and end of the source line) - then the target line cannot be computed over its full length without either extending the source line or cutting back the target line. That was the case in this example. The alignment was too short or the target line too long for the computations to work.
As soon as we selected the full length alignment and trimmed back the target lines to the correct length everything started to work as it should.
Video shows you how