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Autodesk Civil 3D Corridor Creation Management is a learnable and valuable Civil 3D production skill in the marketplace.

The nuance and detail of the construction, design, and maintenance of Complex Corridors is worthy of pursuit. In the varieties of civil engineering and survey projects, we come face to face with these beasts. The Multiple Dynamic Baseline Corridor can become the monster of our own making.

Out here in Civil 3D Land we might say we, “Manage Complex Corridors or Die Trying.”

The Corridor is a Design Manager

The Civil 3D Corridor is a design management tool. A Corridor can be easily adapted to a number of diverse divide and conquer strategies as we shall see. Managed Corridors provide the robust optionality that many civil engineering projects require.

Civil 3D Corridor solutions are, by definition, more complex and manageable than other Civil 3D design and surface building methodologies.

The Corridor is a managed output and published results collector in Civil 3D.

Corridor Baseline and Region creation attack plans deserve a video…


Plan and Manage Civil 3D Corridor Creation

How we plan to create our Corridor Baselines and Regions can affect our workloads dramatically. These topics demand considerable attention and some detailed discussion.

We need to be proactive and systematic about the order we add (create) Baselines and Regions in a Multiple Dynamic Baseline Corridor. We have both strategies and tactics to consider for our practical Corridor design heuristics and workflows.

The Corridor Design State Principles

The Corridor Design State principles and practices should help Civil 3D users accomplish the similar and related Corridor design work that is applicable to many more types civil engineering projects.

We must learn to employ classic Power of Names and Separation of Powers methodologies to create, edit, and manage all the interrelated data complexities of a Complex Corridor.

To review and summarize some of the Complex Corridor Best Practices:

  • Project Data Reference (DREF) management of the design control is essential
  • Plan and Manage the creation of the Baselines and the Regions
  • Know Thy Subassemblies and their codes
  • Employ Sets of Assemblies to manage the cross section design control and Property details
  • Master the Region Create and Edit Tools and the Master the Corridor Targeting Tools
  • Corridor Surfaces are and are not generic Civil 3D Surfaces

 Manage Baseline and Region Creation

Some form of structured Baseline and Region creation plan is essential in Complex Corridor designs. The Corridor Parameters box is currently Baseline creation order based.

We might all wish for a modal, sortable, and filtered version of the Corridor Parameters box in the future. Please, take the time to ask Autodesk for what you need in writing.

Here’s the classic example of Corridor Baseline order - The Civil 3D Intersection Wizard currently adds Curb Return Baselines and their Regions with Assemblies before the other automatically created Baselines and Regions.
Might a different order of Baseline Creation simplify the downstream Corridor editing and maintenance?
You bet.

Our Corridor Baseline and Region creation plan execution effects the conjoined Corridor design control, Set of Assemblies, and Targeting challenges discussed elsewhere and in-depth in this series of Complex Corridor posts.

Plan for the Parallel and Partial

We initially tend to expect that a Corridor Baseline collects sequential Regions of full cross section Assemblies. A simple single Baseline Corridor for a new roadway does exactly that. Nice project work if we can get it.

The single Baseline and sequential Region conditions may exist for many feet of a linear or even a non-linear Corridor design. Common civil engineering design problems usually involve further Corridor geometric complexity. Why we end up with Complex Corridors so often.

In Complex Corridor design scenarios, we often end up with parallel Baselines and partial section Assembly Regions that solve those complicated geometries of the design problem.

Parallel Baselines and Sequential Regions conditions are commonplace for roadway, rail, pipe, and site design Corridor solutions. See the Cook with Civil 3D Corridors post for clarifications.

Plan In and/or Plan Out

Out of training and/or habit we may initially tend to think of Corridor construction from the inside center Baseline out. This makes some sense. Afterall, we must construct Corridor Assemblies from the center out?

We can construct Parallel Baselines with their partial section Assembly Sequential Regions from the outside in.

Site design projects that will include parallel roadway improvements are a classic example where the outside in approach may benefit from an outside in Corridor Baseline and Region attack plan.

Inside, Outside, and Stuck in the Middle

At times, the mesh grading interface between two parallel Corridors and/or design Surfaces is the challenge. It is no surprise that Corridor Ditches and other middle and not centered Baselines remain an all to common Civil 3D user struggle.

We Edit More Than We Create

The capabilities of the Corridor Parameters tab interface means that we can easily spend an inordinate amount of time getting to and then editing the many Corridor Region Property details in there.

Recall that the Civil 3D Toolspace interface and Right Click menus for a Corridor Baseline will get us directly to a selected Baseline in the Corridor Parameters tab. In Complex Corridors, this method of edit access to the Corridor Parameters tab can be quicker than other interface approaches to Region edits.

There is currently no screen driven Corridor edit tool to edit all the properties and parameters of a selected Region. If the Corridor Parameters tab is already open, it is easy to select and locate a selected Region in the tab via the Select Region Tool at the bottom of the tab.

Currently, Civil 3D effectively also denies us access to the detailed Corridor Parameters tab information for Data Referenced Corridors. Now that is annoying. An established Baseline and Region plan helps us employ the powerful project-based tools available for DREF Corridors in our production process.

It should be noted that the create and edit critical path Start Station and End Station properties of a Region are often determined by the geometry of horizontal design control apart from the original Baseline. This fact speaks to the artful need to employ project-based DREF design control; multiple Civil 3D Styles to visualize the design control and the current Corridor output; and the practical employment of the many useful Civil 3D Transparent commands - most often Station Offset (‘SO).

The One and the Many

Sometimes it is worth the management, creation, and naming time to recreate a second Corridor with a different order of Baselines. Sadly, it is most often most helpful to recreate a Complex Corridor when the Corridor has lots of Baselines.

More than one Corridor - another Divide and Conquer approach - is a practical and tactical solution. Consider that the number of Baselines and/or the need for separate Surface, Feature Line production, or exported 3D Solids from a Corridor all may be reasonable decision points or benchmarks.

Corridor Annotation

Corridor Feature Line results can and do drive automated and consistent annotative Point Labels from Corridors. The annotative Point Labels from Corridor Feature Line results are determined by Region Frequencies. See the Intersections and Corridors page for videos and links to posts.

Often, we need the annotative Corridor Frequencies properties to differ from the Corridor Surface or Region resolution properties. The Corridor model that produces this managed project-based annotation is a useful production tool.

Perhaps we prefer to annotate the Corridor Surface(s) instead?
Visit the Cook with Civil 3D Corridors post and watch the Label Style Expression Set video that is included there. The post also includes another video perspective on Corridor based pond design in Civil 3D.

Note again that if the Corridor design control is in project-shared DREF sources, different Corridor creation plans or even Corridor recreation in other working project drawings is much easier to perform and maintain.

The Powers of Names and Complex Corridors

The many and related Civil 3D naming conventions we employ greatly affects our Corridor creation, edit, and maintenance behaviors and daily production performance. Inconsistent conventions we may employ in simple Corridors can become a significant problem as the number of Civil 3D design control Features employed in a Complex Corridor increases.

Corridors are subject to nonlinear growth and/or the growth of powers effect.
Doubling the number of Baselines or Regions in a Corridor can easily more than double the number of named Features employed. See the Manage Sets of Assemblies in Civil 3D post and video for some examples.

The nuance, detail, and Civil 3D user time dedicated to the Corridor Region Targeting process is the classic production problem that Autodesk partially addresses in the Civil 3D 2022.1 Update Targeting interface improvements. See the recent Corridor Targeting Best Practices post and video.

Corridor Baseline and Region Names

The default Corridor Name Templates are set and edited in the Feature Settings for the Corridor in the Toolspace>>Settings tab. Civil 3D currently employs some basic editable strings (e.g. BL) in some of the default name templates that we may want to change. Some of these important Name Templates also supply name defaults to the Corridor Feature Line conversion to Alignment and Profile tools.

The renaming the Baselines, particularly when the same Baseline is employed multiple times in the Corridor, can be helpful to explain why a specific Baseline (an Alignment and Profile pair or et al) is employed in the Corridor.

Baseline Names

By default, Civil 3D automatically creates and updates Baseline Names if the assigned horizontal and vertical design control properties change.

  • Rename Baselines after the proper design control is established and/or repeat the process
  • Civil 3D adds automatic counters to the names
  • We can employ manually adjusted counters in Baseline names to help identify priority order.
    This does not currently affect the displayed order in the Corridor Parameters tab.

Feature Line Baseline Names

Civil 3D requires that all Feature Line-based Baselines must be built from named Feature Lines.

The Static or Dynamic status of Feature Line Baselines is usually important to identify in some fashion.

Region Names

By default, Civil 3D automatically updates the Region Names with a unique counter version of the currently applied Assembly name. For most common design purposes Region names based the assigned Assembly appears to be an acceptable convention. Your needs may differ.

The Assembled Names

Obviously, the naming conventions employed for our Sets of Assemblies, Assemblies, Assembly Groups, and collected Subassemblies have a significant Civil 3D user productivity impact.

Our Baseline and Region attack plan can dramatically effect required design control and significantly the number of Sets of Assemblies, Assemblies, and/or the number of collected Subassemblies required to produce all the many Corridor design output results our project demands.

Baseline and Region Generation

Turning On and Off Baselines and/or Regions in the Parameters tab can and does change the Corridor engine output results.

Be aware that the Show All Regions tool will turn On all Baselines and Regions that were previously manually turned Off.
The Isolate Region tool, although useful, may not always be friendly to our purposes.

We can employ this Baseline and Region On and Off functionality in an Complex Corridor to:

  • Reduce Corridor processing time
  • Identify and inspect specific Corridor Baseline and Region resolution issues
  • Employ near duplicate Baselines and Regions and/or near duplicate Corridors to produce design options and or alternatives
  • Develop and test different Corridor Baseline and Region creation attack plans

Baselines and Regions we employ to embrace these design option advantages should probably be removed from finalized Corridors that produce published Corridor DREFs and/or documentation so as not to confuse ourselves and/or other users downstream in the project.

When a Corridor becomes a publishing project Data Reference, may be an appropriate benchmark.

In all Corridor design scenarios, we must remain conscious of the current Corridor’s Design State and the Baseline and Region creation plan employed.

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