I have used the define target alias once so far for one of my ramps and it worked out. I am trying to replicate the process for another ramp but when I select the same tool it does not find the surface/corridor. I have my ramps in a separate model but referenced into my mainline corridor. In the picture below both my ramp and mainline are targeting existing ground. In the videos I have watched before I am supposed to use "Define Target Alias" to trim one end of the end condition and then use "Corridor Clip" for the other end.
I should be able to see Corridor - RampH, Corridor - RampA, Corridor - RampE as well.
I could be wrong, but you may need to add those corridors as "Corridor References" before they can be seen by the Target Aliasing tool.
I switched to my file that contains the ramp corridors and now I am able to see a varying number of surfaces on the ramps. I still do not completely understand what governs which surfaces will show up on a corridor when using this command but it will suffice for the time being. Thank you for the input.