Civil 3D Feature Lines Not Acting as Breaklines

Applies to:
Civil 3D

Issue:
Feature lines added as breaklines to a surface have no impact—elevations and slopes remain unchanged.

Causes:
The feature line may not have elevations assigned, or it was added with the “Non-destructive” option. If the breakline supplementing distance is too large or the line is not in the correct site, it won’t affect the triangulation.

Solution:

1 – Select the feature line and use Elevation Editor to verify it has elevation data
2 – Remove and re-add it to the surface using Add Breaklines
3 – Ensure the “Non-destructive breakline” box is unchecked when adding
4 – Adjust the mid-ordinate distance to improve accuracy
5 – Confirm the feature line is in the same site as other geometry affecting the surface

Previous Article
Top 3 Insights for Manufacturers - Autodesk 2025 State of Design & Make Report
Top 3 Insights for Manufacturers - Autodesk 2025 State of Design & Make Report

Discover three most powerful insights from Autodesk’s 2025 State of Design & Make Report that manufacturers...

Next Article
Digital Twins in Manufacturing: The Power of FlexSim and IMAGINiT's Simulation Services
Digital Twins in Manufacturing: The Power of FlexSim and IMAGINiT's Simulation Services

Discover how FlexSim and IMAGINiT’s simulation expertise empower manufacturers to optimize operations, redu...

Need tech support? Let us help!

Learn More