Section 4 - Corridor Modeling

The Corridor Modeling toolset is a group of commands used to create 3D designs that represent a new roadway or other types of surfaces. Designers work primarily in 2D files and OpenRoads tools automatically generate the 3D model. Tools for the design, creation, modification, management, and report functions are provided. The tools are accessed by choosing the Corridors tab as shown below.

The 3D model will be generated from the 2D base model design file for CTDOT projects. It is recommended that users take a federated approach to store each corridor model in its own design file for large projects that have several alignments and sites. Small projects may have the data in a few files while larger projects will use multiple files for the geometry, terrain, superelevation, and the 3D model. All these files can reference one another to present a complete model of the project.

Each road within the project is used to define a 3D corridor model representing the proposed design. A corridor consists of an alignment, profile, and a template defining the initial roadway typical section. Multiple templates may be applied within a corridor to better define the roadway. Additionally, transitions and other modifications to the template can be defined using various modification tools. As changes are made, the 3D corridor model is automatically updated.

 

» Corridor Model 3D Graphics

When a corridor is processed, the 3D model is generated in a separate MicroStation model named “Default-3D”. The corridor graphics consist of 3D line strings and 3D surfaces for each design component. The example below shows a portion of the pavement for a corridor with the individual pavement layers that were generated for the 3D model as well as a portion of the side slope.

 

 

When the template is processed, the template points are connected between template “drop” locations to form the longitudinal break lines that are used to create the proposed surface. An example of the longitudinal break lines plotted from a 3-dimensional design surface is shown below.

 

 

Only the top template points are used to create the proposed surface mesh. Points below the surface are excluded from the proposed design surface.

The sub-surfaces can be included in the proposed cross sections as “components” or alternate surfaces. These components can be used for volume calculations. Corridor 2D Graphics In addition to the 3D graphics, the corridor modeling process draws 2D plan view graphics. These graphics can be used to generate the plan sheets for the project. An example of the 2D plan-view graphics drawn as part of the corridor modeling process for the curbing, shoulders, snow shelves, and fill limits is shown below.

 

 

» Corridor Modeling Workflow

The workflow for corridor modeling is summarized below.

1. Create Civil horizontal and vertical geometry element(s).
2. Define templates for the project.
3. Set the active terrain (existing ground).
4. Create a corridor based on the horizontal and vertical elements.
5. Add template drop(s).
6. Add horizontal and/or vertical controls for template points (optional).
7. Define any transitions and connections.
8. Associate superelevation information.
9. Review the results and adjust as necessary using additional controls, such as end condition exceptions, secondary alignments, parametric constraints, or target aliasing.
10. Continue the process/review/modify until results are what you want.