Best Workflow for Segmenting Linear Design into 1km Surfaces (LandXML / Volumes)

[komahony]

I am currently developing a linear design (50 km in length) where elevations are specified at 1 km intervals, with each kilometer having a distinct elevation value provided in tabular form.

My goal is to generate surfaces for each kilometer segment and export them as a combined LandXML for volume calculations in external software (either per km or for the full extent).

At present, my workflow is as follows:

• Create polylines representing the north and south extents of each segment
• Convert these into feature lines and assign elevations
• Add them as breaklines to a surface
• Apply a boundary and then create cropped surfaces for each kilometer in separate drawings

However, because each kilometer has a different elevation at its start/end, the resulting surfaces introduce slight slopes between segments. My current workaround is to offset the start/end lines by 1 mm to prevent adjacent surfaces from interacting.

This approach is quite cumbersome, particularly when working at very small tolerances (e.g zooming in to join polylines accurately).

Is there a more efficient or robust method within Civil 3D to:

1. Maintain discrete, flat surfaces for each kilometer segment with differing elevations, and
2. Export them cleanly for LandXML based volume calculations?

Any guidance or alternative workflows would be greatly appreciated. 

Processor Intel(R) Core(TM) i7-14700HX (2.10 GHz)
Installed RAM 64.0 GB (63.7 GB usable)
System type 64-bit operating system, x64-based processor

[ecfernandez · Accepted solution]

Hi @komahony, are those surfaces you are talking about corridor surfaces? If so, split your corridor every 1KM and then turn off the regions you don't need. Export one by one turning off/on regions accordingly. 

[navya_gelli]

Hi @komahony ,

I wanted to check in and see if @ecfernandez response was helpful, or you still needed assistance, or you found a solution to your question already? Let us know if you need further assistance by providing an update or if you have found a solution, please share it with the community so other members who may have the same question could learn from your experience.

All the best,

Navya | Community Manager

[komahony]

Thanks for the reply, much appreciated.

I haven’t used corridors much before and have been working primarily with surfaces, are regions similar to boundaries?

I’ve completed my task, but it was quite time consuming. I created a surface for each 1 km segment at its design elevation and added a 1 mm gap in between so the elevations don’t interact. I exported a LandXML for each KM as individual surfaces, and also one large LandXML containing all the KMs pasted into a new surface. I plan to use these for conformance models and volume calculations for specific KMs as well as for the full 50 km.

I’m still learning Civil 3D, so I was just wondering if there’s a faster or more efficient way to do this?