Pack Dances with Parcels – Part 7

Tags parcel, site parcel, slide, swing, free form, frontage, grading, attached segment, parcel segment

Some say AutoCAD Civil 3D Parcels are a bitch. Parcels can run in packs like wolves. Last time we learned that the attached Parcel segment can perform the functions of the Alpha bitch in a wolf pack. She’ll try to keep the puppies in order.
These days we have “dog whisperers”.
As far as I know there have been few wolf whisperers in history since the bros Romulus and Remus.
We know how that turned out? But Rome wasn’t built in a day.

Is it Time to Become a Parcel Whisperer?

The Parcel Posts - a study guide to Read and Test in AutoCAD Civil 3D
Site Parcel Essentials – Part 1 | It’s Not Yo’ Daddy’s Parcel – Part 2 | To Edit Parcels is to Create? – Part 3 | Parcels Have Priorities - Part 4 | A Strange Universe of Parcel Inverses and Mapchecks – Part 5 | Dances with Parcels – Part 6 | Pack Dances with Parcels – Part 7 | Cycle Manipulations of Segments – Part 8 | Select Manipulations of Segments – Part 9 | Visual Manipulations and Many Segments – Part 10

Create By Area and By Frontage

The Parcel Slide and Swing tools in the menu are driven by additional interactive Parcel Sizing Parameters which, in effect, act like rules to define some of the specifics of the attached tangent Parcel Segments they create. See the previous post to understand the essentials of the “attached” Parcel segment.

Parcel Layout Tools Expanded

The Slide and Swing tools work from the establishment of a temporary Frontage. A user defined Frontage kindly ignores the differences between single segment and multi-segment Parcel segment input data.  Thankfully because of Frontage you do not have to manually pick each Parcel segment individually.

I do whine about the Frontage definition process and the fact you have to bail and restart to change it if you initially blow it. It’s too easy to blow the Frontage definition. If you employ useful tools like the Extension OSNAP to create a tricky Frontage, Civil 3D currently seems to have issues finding and constructing the next Frontage. Don’t forget to Refresh the Parcels collector in the Toolspace, reload the Parcel Layout tools, and restart the tool.

Based on the Frontage you define the Parcel Sizing Parameters will allow you to search through a variety of potential parcel solutions.

If a solution result is possible with the current parameters, Civil 3D will display you an on-screen potential solution that meets the current parameter specifics. Nothing on screen is real at this point. Change the parameters – get a new displayed and still interactive result.

Parcels By Swing

Nothing From Nothing Means Something

No displayed solution means that for your current parameters nothing works. This is good visual QAQC, but that assumes you know nothing to see on the screen means something and that not a failure in the software. Does the command line tell you?

It is important to Read the help about the meaning of the Parcel Sizing Parameters. How the values practically interact is another challenge made easier by understanding what you are telling the tools. There’s no way around practicing with the tools either. No reps – no results or worse… bad results.

What may not be so obvious here is that the specifics of the Frontage definition (direction and distance) combined with the current parameters allow you considerable design leeway.
For example: Is it possible to start your Frontage 100’ down from the endpoint on a segment?
Do you want Automatic Mode to get multiple Parcels at a time or create a Parcel?
Do the current Parcel Sizing Parameters make what you want impossible?
In effect, you can work down to smaller parcels in a step by step fashion or attempt to do a lot of lots all at once.

Parcels By Slide

Want to Dance? Do you Slide or Swing ?

  • A Slide solution creates attached segments from the Frontage.A Parcel Segments created by Slide continue to reference the input segment at the connection location. The search is outward along the defined relative Bearing for the first Parcel Segment found in the current resolved Parcel.
  • A Swing solution creates attached segment to the Frontage.A Swing segment works from the defined Swing point (on and attached to a segment on the resolved Parcel boundary). The searches are for the locations on the Frontage within the current resolved Parcel.

Subtle Dance Steps

It helps to have a plan of attack. It helps to consider that the Frontage definition relative to the choice of tool is important to the potential reactive grading you can establish at the same time. Would beta attached segments based on an alpha attached segment from the inside be easier to build and maintain than an outside in approach?

Edit Attached Parcel Segments

Currently Civil 3D doesn’t include the functionality to flip an attached segment so the key connection location could relocated from end to end.
You cannot readjust the relative angle of an attached segment either. Arrgh.

Will these tools find Parcel Segments “inside” the Parcel that are not on the Parcel boundary?
Yes, but you’ll also probably not always get what is temporarily displayed and what you may expect as a result. In other words, the Slide and Swing tools were not built with internal Parcel Segment alternatives in mind.

A Segment Disconnect

It is also not really obvious that Copying attached Parcel Segments creates unattached Parcel Segments. In other words, you can remove the Slide or Swing point attachment to a segment if you need to. That act of violence has consequences.

Are you paying attention? Did you forget about the Grade and Chop Duality we keep seeing in the Site Parcel?
Did you recognize that the Free Form, Slide, and Swing tool tangent segments hook up to the derived elevations of the selected Parcel’s perimeter.
You can grade the outside and affect these internals. The elevation matchup on the other side of the Parcel is always relative. Therefore, get the primary alpha segments close to grade before you chop up the areas.

Remember the Elevation Editor will slam selected or all grade breaks in either a Parcel Segment or a Feature Line to any Surface – an intermediate surface for example.

Connections Matter

It is also not obvious that the type (single segment or multi-segment) of the underlying geometry that your new segments attach to affects what you can do afterwards by Grip edit and with the Elevation Editor.
In other words, after the temporary Frontage of the Slide and Swing tools is gone you are stuck with the “nature” of the input segments unless you edit them.
Hey that’s another reason why we have those join, trim and break tools in the Horizontal Geometry edit panels.
The nature of the input segments may make a big difference in your total edit time. Multi-segment (polyline) or (better yet) referenced Alignment input allows you more flexibility.

Elevation Editor tweaks to attached alpha segments drive cascading grade changes to the beta (secondary attached) segments. Toss in a few key Elevation points and massage to grade both the attached segment and the grade breaks at the ends of the attached segments.

Add Segments As Breaklines

This interactive edit capability is maintained when the Parcel Segments are added as Breaklines to a Surface. You can Supplement interpolated points when you Add as Breaklines. The Supplemented data updates dynamically too- this is derived dynamically from the Parcel segment input data.

Currently, Civil 3D seems to ignore the Mid ordinate distance specification for Supplemented curved Parcel segment input. Not Good. You can employ different Supplement values for separated curve segment input or employ additional Feature Line inputs (from a separate Site) to correct the issue.

A Surface From Attached Parcel Segments

Feature Lines May Interact with Attached Segments

Back in the first post it was stated the Feature Lines don’t interact with the other potential Site Parcel Features to create resolved Parcels. If multiple attached segments interact with a Feature Line this is NOT true.
Remember that Feature Lines will create nodes in the Site Parcel model no matter what.
Simply put - suddenly a Feature Line that crosses multiple attached segments will start affecting the resolved Parcels by affecting the found end locations. Ouch!

I consider this a bug. The first segment of the Feature Line is apparently marked in the Parcel model as a Feature Line and exempt from resolution. Apparently the subsequent segments in a multi-segment Feature Line are not so marked. The dynamic Parcel model responds in kind. Attached Segments see the other segments as valid resolved Parcel contributors and find their new end locations.

What’s the fix or work around?

This is easy. Recognize the Site Parcel duality. The Parcel duality requires separate management containers – different Sites.

Keep your inter-parcel Feature Lines and their related Gradings in a separate Site Parcel from the subdivision Parcel Segment work and their Gradings. This is where the Feature Line Style Priority property comes into play. Always employ Feature Line Style Priority to manage the many things to produce a dynamic and consistent desired result.

Features from multiple Site Parcels will happily both interact with any surface model(s) you choose.

Sorry. I know you had to ask,

“If both Feature Lines and Parcel segments can contribute to a surface, are the Parcel Segments more significant than Feature Lines?

No rocket science here. For Surface Breaklines everything is equal by entry order until you solve the issues with the Resolve Crossing Breaklines tool found in the Surface Ribbon Analyze panel. That’s a post for a different day.

A Friendly Reminder

Hey? Let me remind you again. Did you think to create copies of the start Site so you can keep your options and alternatives open in the future? We all change our minds. We have to go back and check against something.

Has this onslaught of Parcel posts changed your mind a bit about those stupid and annoying Civil 3D Parcels? I hope so.

Next time we’ll chat about the Manual Manipulations of Parcels.