Site Grading Corridor Design Control in Civil 3D

Tags grading, corridor, site design, Assembly, Subassembly, Frequency, baseline, region, bowties, target

Our decisions and choices about the mission critical Design Control in Site Grading Corridors are where the rubber hits the road in a production environment in Civil 3D. Like all things in Civil 3D Site Grading Design Corridors favor the iterative development of improved and managed design control.

There are lots of potential forms of Design Control at work in a Complex Corridor – a multi-Baseline, multi-Region Corridor.

The number of Corridor Design Control choices can be overwhelming. A Separation of Powers perspective appears to be the required order of the day.

Site Grading Corridor Baseline Design Control

Every potential Corridor Baseline has an Alignment/Profile pair or a Feature Line to provide the fundamental horizontal and vertical control. This Baseline design control becomes the mission critical path the Corridor engine follows to construct and connect the other pieces in that Baseline portion of the Corridor.

Civil 3D Feature Lines are our familiar Civil 3D grading friends. We commonly tend to jump on and then depend on Feature Line design control too quickly.

The good news – we know Feature Lines. The bad news from the design control perspective - Feature Lines are individualized. They are not a project centric but drawing centric form of Civil 3D data behind. Feature Lines lack vital project DREF capabilities that are typically the more productive method to employ in Civil 3D.

We can build horizonal and vertical Baseline Design Control for Regions and design control for Targets from extracted Corridor Feature Lines with both linked dynamic and/or static Feature Line sources. We can also get the vertical control, both dynamic and static, from temporary Surfaces.

To learn how to do these tasks with the Civil 3D tools is important. Why and When to employ the various methods is worth taking the time to experiment with.

From the One the Many

If we learn how to manage, massage, and successfully convert our Feature Line friends into Alignment/Profile pairs, we gain in both that vital DREF project context and more adaptive design control. The trick is to remember to create, clean, and manage the DREF data behind.

How we go about this Feature Line to Alignment/Profile pair conversion process matters.

The Quick and Dirty

When in doubt the LandXML export trick of a Quick Profile of a Feature Line works. Hint: You probably want to rename the Alignment and Profile in the LandXML before you import the data.
Odds are you may also want to take the time to clean and manage both the new horizontal and vertical control results.
Remember probably the last place you want that LandXML import is into your current drawing.

Then again – the consideration of where that Feature Line got its horizontal and/or vertical data from in the first place might favor other Civil 3D Ribbon tool approaches. That statement should make you scratch your head and think about that a bit.

Parents with many Children

One Alignment can have many Profile children. That can include convertible and therefore editable Surface Profiles from multiple temporary design surfaces. To be clear…Can you say editable Best Fit Profile?
OK. Maybe you just want to trace over this and that? We can create From the Many a One.
When we talk about carefully crafted Region Targets methodology, we might get away with just the static or dynamic multiple Surface Profiles themselves.

One Alignment can have many Offset Alignment and Offset Profile children. The reality that you can drive the Alignment/Profile Child design control for Baselines and/or Region Targets from managed DREFs or use those Offset DREF sources themselves in Civil 3D is a not so obvious but powerful benefit.

The Children of DREFs

You can test design control Offset constructions from DREFed Parents and easily go back and recreate the finished solution in the source DREF. We just need to bother to take the time to do the DREF maintenance do.

Which might leave us with the next dangerous question –
Can we build new design control from a DREF Corridor?
Certainly. If you are willing to take the time and discipline to manage that incremental complexity in your project context.

Maybe we want to separate our more planar Sheet solutions from our detailed Structures and Slopes solutions?

Baseline Regions and Applied Assembly Sets

Every Baseline Region has cross-section design control in the form of an Assembly collection of Subassemblies and/or PKTs with their applied Properties and Parameters.

The Corridor engine builds complexity from simplicity.

We can employ improved Corridor settings like the Corridor Bow Tie Settings to reduce the repetitive manual work required to achieve a repeatable and consistent results in our Site Grading Design Corridors.

We discovered earlier in the Civil 3D Grading Multiple Baseline Mechanics and the Multiple Slope Site Corridors in Civil 3D posts that often Less Design Control Detail Becomes More in the Site Grading Corridor context.

These Region Assemblies are best seen and managed productively as interchangeable and related Sets of Assemblies in real world design projects. I try to point out that productive Civil 3D Assemblies work in managed packs. See the initial Civil 3D Assembly State Management post.

Baseline Region Design Control

Every Baseline Region has important and manageable Frequency considerations.

Region Frequencies

There is that particular perpendicular aspect to Corridor Assembly application we can maximize and employ to our advantage. We explored some of the why, when, and how effects of applied Frequencies in the Civil 3D Corridor Site Design Considerations post in this series.

When to employ special Frequencies and when not to do that, is perhaps more important than how to build special Frequencies in the first place which is not difficult.

When we better understand the Frequency relationships between our Baseline Design Control geometries and the Region’s applied Frequency Properties, we can generate far better Site Grading Corridors, collected Feature Line results, and in the deliverable end game’s automated and managed annotation of the same.

Region Frequency Feature Line Annotation

Any Civil 3D Corridor-based Feature Line can generate Point Label Style annotation by Point Code at any Frequency and location in any project drawing. Civil 3D Toolbox Corridor reports will produce the data. See the Civil 3D Corridor Label Details post and related videos.

The new Project Explorer for Civil 3D makes this process even easier than ever and PE can remember and repeat what you did the last time. More on that path to more automated annotation in another upcoming post.

Baseline Region Target Control

Choices, choices, and yet even more choices says what needs to be said about Corridor Region Targets.

Can None be Better than Some?

When we supply no Target design control to a Region the assigned Region Assembly collection of Subassemblies and/or PKTs drive the Target control. Repeat the Corridor mantra - Less can be More.

No assigned Region Target requires the least amount of manual Corridor maintenance and upkeep but requires more careful attention to the Subassembly and PKT Properties and/or Parameters themselves. One significant reason why task-based, planned, and managed Sets of Assemblies are an important Corridor design resource.

The downside to this Assembly approach is the current difficulty in Civil 3D of updating easily those Subassembly and PKT Properties and/or Parameters across many similar Assemblies. Currently, this is why pre-built Sets of Assemblies seem to make more production sense.

Target Objects and Features

These days the Civil 3D Corridor engine can employ almost anything as a Region Target if the form of the Target object includes to requisite horizontal and/or vertical control geometry. Multiple types of Targets are supported from simple AutoCAD primitives to almost all Civil 3D linear Features.

Feature Lines do both forms of design control. Does that make Feature Lines the easiest and best Target to employ?
Not necessarily. Feature Lines and ACAD primitives are drawing specific and/or create XREF dependencies in a drawing and within the Corridor Feature collection. These create behind the scenes potential complexities that can be difficult for others to see and understand if things go bad further down the Site design process.

Put another way – Civil 3D favors working project drawings that produce the managed data behind for publishing drawings. If we attempt to force Civil 3D working drawings perform both functions, it is always more problematic and can introduce performance issues that often assault us at crunch time.

Project DREF Targets produce the more consistent, more adaptive, and better managed results. This is a goal not a requirement. The more we do the work, the better the results. DREF Targets do require more project-centric Civil 3D user DREF creation, maintenance, and management skills.

Sorry. The development and application of these Civil 3D skills take practice that we cannot escape.

Site Grading Design Corridors like all things in Civil 3D favor the iterative development of improved and managed design control. We can rely on the demonstrated and proven ability of Civil 3D DREF sources and functionality within a managed Civil 3D project structure to help us get that work done and produce effective production deliverable results.

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