AutoCAD Civil 3D

[#1]

Hi, everybody.

I work with railway designs and we have many rock cuts along the corridor. I've already tried many solutions for this (even SAC) and it didn't come as expected.

The assembly we should use would be something like this:

EG SURFACE

ROCK SURFACE

The blue line represents the cut area I need and the red line just the 'projection' the dayligthining of the blue line should follow after targeting the Rock Surface. 

I tried to create some assemblies using the default C3D subassemblies and the best result I could get was doing a auxiliar corridor first targeting the rock surface so I have the points (daylights) where the 1:1 slope should begin. 

Then I created another corridor using this assembly:

I have a generic link to Rock Surface (0.20:1 Slope) then the LinkWidthandSlope to target the daylights of the first corridor and the DaylightBench targeting to EG (1:1 Slope).

Of course when I create the corridor it shows a bunch of errors although if I generate the corridor surface using Top Links it works like I want...

except for some points where the surface doesn't follow the top links...

It's not a big deal as I can edit these wrong points and have the correct surface but as we have many rock cuts it would take a long time to correct it and also any change in the rail profile would regen the corridor surface and we would have to edit it again.

So... anyone knows a better solution to create a corridor like this (and with no errors)?

Thank you, and sorry about my English mistakes.

[#2 · Accepted solution]

I think that your best option here is to use two corridors to solve this.  The first one would be to build the red lines, and you would have to use a series of conditional subs and generic links to establish a point at the interface with the rock surface as you build up to the EG surface.  Extract the featurelines at the intersection of the red links and the rock surface.

The second corridor would be building the blue lines.  Start with a slope to surface up to the rock, then use a stripping sub to follow the rock surface out to the feature line that you extracted earlier.  Finish it off with another stripping sub which follows the surface created from the previous corridor up the blue links to EG.

The hardest part is going to be working out the logic of the conditional tests,

[#3]

Thanks a lot, sboon.

The stripping subassembly was the solution!

I needed two auxiliar corridors to get the final corridor and surface...

This is the blue line assembly...

I also had to use a final DaylightBench to be able to create Datum surface 

The final surface

and the best part.. with no errors in the corridor!

Thanks!