How to model corridor from edge toward centerline

[Neilw_05]

I brought this idea up in the not too distant past but I want to query the corridor gurus to hopefully find a way to make it work.

When a corridor has lots of variations along the outside edges of the travelway it can make corridor modeling from the centerline a cumbersome task. This is because we have to create a template and region for every scenario where the edge treatment varies from right to left.

To simplify the process I have considered creating alignments for the edges of the roadway and adding them as baselines to the corridor. This way we can create just a few assemblies for the various edge treatments and apply them independently to the left and right baselines. These assemblies would then target the centerline profile to model the crown of the roadway, just as we do for curb returns.

In my experiments it seems to work nicely, but I encountered problems when viewing cross sections and calculating quantities, since the software is designed to work from the centerline baseline. Would it make the sections work if I add an assembly to the center baseline with short segments of pavement and stretch them to the edge baselines?

Another challenge is generating the profiles for the edge of the roadway to use for the baselines. These profiles would need to follow the centerline at a given vertical offset to provide the desired crown slope. Any edits to the centerline profile would need to be reflected in the edge profiles. This could be done by creating a surface from a grading object that is built on a featureline generated from the centerline and using that surface profile for the edge of roadway baselines. Another would be to stretch the center assembly to the edge and generate a profile that way. I experimented with that idea but couldn't figure it out. I'm looking for other techniques here as well.

So my question is: can this workflow be made to work somehow? What ideas do you have?

Neil

[Neilw_05]

I've finally gotten around to testing this concept and so far it works nicely. The key to making it work is to create a seperate corridor for the lane cross slopes and use it to create a surface that can be sampled by the edge of pavement alignments. The sampled surface becomes the profile for the edge of pavement baselines. This intermediate corridor step is necessary to get around the circular reference problem.

I haven't tested super elevation yet but sections look fine in section viewer as well. I find this technique simplifies the corridor modeling process in several ways (such as fewer assemblies and regions) and makes the corridor much more adaptable to varying edge conditions.

Thanks to the enhancements to corridors in 2013 this is now possible.

[sboon]

Neil can you post a drawing or some pictures to show what you're trying to achieve?  I may already have a solution for you but I want to make sure that we're talking about the same thing first.

[sboon]

An interesting problem.  This is all one corridor with a baseline and region building the lane from the center out to the second alignment, then a second baseline with three regions for the sidewalks and a driveway.

[castled071049]

Unless I am mistaken in what you are trying to accomplish, it sounds to me like using Conditional Subassemblies is the ticket. We use the ConditionalHorizontalTarget (CHT) almost exlusively for the main corridor baseline. We attach CHTs to one main assembly for each situation: driveway, parking bay, ditch, sidewalk, normal curb & gutters, etc. Then just put targeting polylines where you need a ditch, or a driveway, etc., and the assembly puts it there for you. No messing with lots of assemblies, baselines, regions, alignments, and profiles.

In this manner, you only need one baseline and one (albeit complicated looking but simple nonetheless) assembly for your entire main corridor. If changes are made in design (e.g. a parking bay gets extended or moved) you just adjust the targeted polyline and the corridor rebuilds to suit.

Curb returns at intersections are a different matter, but at least the main corridor is simplified.

[Neilw_05]

You have the right idea Steve. I'll post a Jing Screencast to show what I'm doing when I get a little free time.

[Neilw_05]

Hi,

I understand how conditional assemblies work but I'm not real fond of using them for horizontal conditions, mainly because the targets are not dynamic to changes in the corridor alignment or profile. Using this edge to center technique everything is tied together and dynamic. If you need to move a driveway, just drag the region grips and everything stays tangent. I also think it is simpler to just change out an assembly for a region when circumstances call for it vs. adding to or manipulating a conditional subassembly.

[Neilw_05]

Here is a screencast showing how the corridor behaves when modeled from edge to center.

Note how the edges can be manipulated indpendently. Consider how many regions and targets would have to be configured if these variations had to be modeled from the centerline.

http://screencast.com/t/4c8PqwMH6kfY

[SkipBurns]

I've started having 2 baselines in my corridors (even though it's really the same baseline twice) so that all my assemblies are only for one side (Left or Right only).  All the assemblies start from the baseline and work out, but only to one side.  It helps me to have a lot fewer assemblies and makes changes much easier.

As an example I only need:

Left - Curb - Daylight

Left - Curb - Sidewalk - Daylight

Left - Driveway

Right - Curb - Daylight

RIght - Curb - Sidewalk - Daylight

RIght - Driveway

Instead of:

Left - Curb - Daylight - Right - Curb - Daylight

Left - Curb - Daylight - RIght - Curb - Sidewalk - Daylight

Left - Curb - Daylight - RIght - Driveway

Left - Curb - Sidewalk - Daylight - Right - Curb - Daylight

Left - Curb - Sidewalk - Daylight - RIght - Curb - Sidewalk - Daylight

Left - Curb - Sidewalk - Daylight - RIght - Driveway

etc.

[Neilw_05]

That is another way to do it. It can reduce the number of baselines but it may require a bit more complexity in the corridor properties since all the lane pieces that are part of the assemblies and would have be mapped to any width or elevation targets. Also if the pavement structure needed to be changed you'd have to update all the assemblies with lane pieces.