As a surface and grading geek I must say I love the Corridor engine in AutoCAD Civil 3D. Yes. I still employ a Feature Line or two (and even some Parcel Segments and Figures in design grading). I attack almost everything grading with a corridor model. Inside the Corridor Feature you get better horizontal, vertical, and cross section control, more output, better roundtrips, and more options. All of that often makes the small extra work that’s required worth the effort.
Here’s the Good News - This is not rocket science. It’s a learnable skill.
Complex Corridors from Intersections
I tend to employ Intersections as often as possible. You can employ an Intersection where you might never expect an intersection to work. You may not want the whole intersection anyway. I use Intersection wizard in a step by step fashion because I’m lazy. I hate creating related horizontal and vertical control the hard way. The Intersection wizard can save you time and energy when carefully and thoughtfully employed. That’s a subject for some other posts.
I bring up Complex Corridors from Intersections here because the process of creating these dishes makes you think about corridor modeling in a different way. When you employ Intersections, you must learn to create and manage multiple Baselines with multiple Regions with an entirely new level of skill.
How Many Baselines Do You Need?
This is like the infamous question about Existing Surfaces,
“How many existing surfaces are there in a project?”
Most people answer, “One.”
I say, “As many as you need.”
Civil 3D seems to get demoed and taught all the time employing “salmon steak” Regions. Take the big ole red fillet of fish and chop it cross wise into steaks. We could also call them “pork chop” or “tenderloin” Regions if you prefer the “other white meat” or a “beef cake” analogy instead.
Sorry. I was hungry when I started this post. The ole chef skills never truly die. If you wack up a few big swordfish, a ton of fish, and more than a few butts, the picture and the skills stick with you.
Let’s Cook It Up
I suggest that we tend think about corridor Regions as breaks in the horizontal structure of the corridor. That’s what a Region does in part, so that makes sense. However, we do tend to get focused on overly complex (across the entire grain) Assemblies. The approach works to solve many classic civil engineering problems. Complex Assemblies, however, may also serve to make the management of all the intricate details of many design problems more difficult. It misses the true depth of possibility at our finger tips from right inside the Civil 3D Corridor.
The Civil 3D Corridor Feature is a design management tool. A Corridor can be easily adapted to a number of diverse divide and conquer strategies. The Corridor functionality allows us to temporarily reduce the design complexity to test and perform “better” design and easier quality assurance and control.
Are you still working at your design with all the Baselines, Regions, and corridor surfaces “on’ all the time?
Dude. Use the checkboxes.
What about Linear Ribbons?
Who said we can’t separate the roadway, levee, or channel design itself from the side conditions? Instead of steaks we get ribbons or strips when we employ multiple Baselines in this fashion. True, the Civil 3D corridor engine is not quite as adept or easy to use this way at first. You are going to have a bit more manual maintenance of the corridor output to maintain the relationships in the Alignment | Profile control. The tools are there – Alignment from Corridor.
How to use and manage the control well takes practice.
Yes. Where you keep the referenced control you create matters.
If you practice the technique, you’ll get better at it quickly.
The Baseline ribbon technique often makes a lot of sense as a way to manage the more complex details that come along in many real world projects. Here a ditch, here a wall, here a guardrail, here a pond, etc. Our new Baseline ribbons can be easily carved into manageable strip steak Regions.
You can extend the strip steak (Baseline ribbon) approach. You can do shish kebob Regions once you get the hang of the idea multiple linear Baseline concept and technique.
I should put that another way. No one said you cannot employ the exact same horizontal and/or vertical control in multiple Regions down a Baseline ribbon. First, you want a piece of meat from this Baseline Region; next an onion from that Baseline Region; then a tomato from that Baseline.
Look carefully at your grading problem. Are you switching between a number of standard partial cross sections with a few exceptions? Might not even those exceptions also benefit from some systematic isolation by a secondary Baseline and Regions? You betcha!
Many Assemblies use Subassembly tools that include “stacks” of links. But Corridors can produce and manage multiple Baselines with “stacks” of Assemblies too. You could call this the lasagna or cordon blue Baseline approach. I tend to build and test these parts in a temporary corridor(s) and include the results in a more managed corridor model when they’re done. We do have to bake and cool the cake before we decorate it. Don’t we?
A simple Stripping Assembly is easier to deal with and to QAQC this way. Hey even those staged earthwork surfaces or those intermediate surfaces you will probably also need to construct them are only a new Baseline and Region away.
Presentation Matters so Preparation Matters
We need better Style tools to be able to visualize this sort of detail.
Just how many Code Set Styles, Alignment, Profile Styles, etc. are you going to want to have available to do this sort of work?
Maybe a standardized approach to Civil 3D Style and some user friendly management of all of that is something to consider?
Frankly, very few people have the time, money, and experience to build this sort of integrated detail from scratch unless it’s what you do.
There’s a reason we make a Jump Kit that includes the largest collection of fully integrated and tested Civil 3D Styles you can get anywhere – It’s about production, visualization, and publication flexibility.
Feast and Enjoy!