Best practices for breakline development

Last updated: 2025-04-18

Review project development standards

1. Review FDM 15-5 Plan Preparation-Methods

   1. FDM 15-5-3 CADDS Directory and File Name Convention
   2. FDM 15-5-7 Design Models

Review project deliverables

1. Plan

   1. FDM Chapter 15: Plan Preparation
   2. C3DKB Plan production
2. Construction Data Packet
   1. FDM 19-10-43 Digital Data Exchange
   2. C3DKB - Data for Construction

Review constraints and construction methods

1. Review constraints (Right-of-Way, Environment, Utilities, etc.)
2. Review earthwork materials involved with the project
3. Determine staging/paving widths/jointing early in design
   1. Will there be multiple staged “existing” ground surfaces?
   2. Is there a need for temporary drainage accommodations?

General

1. Keep Civil 3D object data single source
2. Keep the data flowing down stream. (Follow the Civil 3D Project Data Map)
3. Keep files organized and data clearly labeled.
   1. Will I or another coworker be able to pick this up in a few months and understand the design model?
4. Use standard naming conventions to take advantage of WisDOT custom targeting tools
5. Try not to rename objects once they have been consumed in other drawings
6. Don’t permanently store design files on your C: drive
7. Utilize training materials and opportunities, co-worker experiences, CAE Support
8. View designs in 3D!
9. Keep it simple (or at least as much as possible)

Breakline Modeling

WisDOT Subassemblies

1. Use subassemblies that allow you to be flexible as design progresses.
2. Use unique point codes for better breakline continuity.
3. WisDOT subassemblies allow for multiple parameters to be targeted.
4. For subassemblies that require targeting, name them so you know what the target should be.
5. Don’t forget about WisDOT General and Autodesk Generic subassemblies.
6. Create corridor assemblies accounting for all typical section variability.

Corridors

1. The purpose of the corridor in our design workflow is to create the longitudinal breaklines of our proposed work surface models.
2. Determine critical baselines and alignments for modeling and cross sections early
   1. Corridors always run perpendicular to the baseline used so regions should be developed to maximize perpendicular efficiency within the design
      1. May need to adjust alignment location (example roundabout)
      2. Set up to match proposed jointing and paving operations
      3. Allows for perpendicular sample lines and accommodate dynamic labeling from frequency lines
      4. Can sample multiple corridors
3. Create a storyboard/plan of the design model progression to:
   1. help develop a clear understanding of the elements required
   2. the timeline in which the elements need to be developed
   3. the relationship between the elements of the design.
4. Corridor layout affects the use of boundaries and the hierarchy of pasting surfaces together to define the refinement surface.

5. There is no single modeling tool or workflow that will work for every design scenario. The focus should be on finding ways to develop the feature lines or breaklines that best define the geometry and cross slopes.

6. Keys to dynamic corridor development

   1. Use a target oriented philosophy in corridor design

      1. Alignments, Survey Figures
      2. Control profiles (VPI profiles, slopes, offset widths)

   2. Conditional subassemblies

      1. Look for potential areas of change in cross section geometry

   3. Use of Setup surfaces if needed to establish proposed profile elevations

   4. Intersection objects, Connected alignments

   5. Target Dynamic Feature Lines from adjacent corridors

      1. Separate corridors for the median and mainline roadways

7. Build out incrementally, turn off baselines, regions or corridors to help trouble shooting, make sure each piece works before moving on.

8. Include additional frequencies at the following locations:

   1. Begin and end transitions to horizontal and vertical geometry changes to proposed work.

      1. Begin and end of lanes and shoulders and their slope transitions
      2. Begin and end of subgrade, side slope, and pavement transitions
      3. The beginning of the 15:1 taper, and posts 1, 5, and 9 of Midwest Guardrail System (MGS) Energy Absorbing Terminal

   2. Spot location features that impact roadway geometry. Examples of this include:

      1. Entrances (driveway may be half-section)
      2. Culverts crossing the cross-sectioned roadway

   3. Significant changes in the existing terrain between regular cross section intervals

9. Using code set styles like "Color by Link - Point and Link Codes" can be helpful to review corridor designs

Surfaces

1. Create Corridor and Refinement Surfaces right after creating corridor

2. Do Not create corridor surfaces entirely from links, supplemental lateral breaklines are ok

3. View in 3D!

4. Evaluate and adjust

5. Avoid use of surface editing tools. It is better to make changes through corridor tools, adding breaklines from feature lines and 3D linework, and the Civil 3D grading tools.

   1. The use of surface edit tools will make changes to the surface model. However, those changes may not be reflected in the surface breakline delivery and will not correctly convey design intent to the contractor.

6. Using a small contour interval is helpful when checking for surface quality.

Breaklines/Cross-Sections

1. Cross sections are a by-product of the design process.
2. Compare breaklines to pavement file
3. Cross sections are based on surfaces
4. Check surface against corridor sections
5. Evaluate and adjust
6. Run the Design Surface Data Extractor periodically throughout the design to review breaklines (this means not just before PS&E)
7. Use the Create Verification Surface tool to make sure surfaces created from extracted breaklines match the design surface.
8. Run the Assign CDP Breakline Layers tool to place breaklines on layers that make sense to the contractor.