Dances with Parcels – Part 6

Tags grading, breakline, parcel segment, parcel, site parcel, topology

What did we get ourselves into when we started a simple write up on Parcels?
Ah well. Inside AutoCAD Civil 3D there’s always more to the story.

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

As I said in earlier posts our expectation and tool use habits sometimes get in our own way. We need to keep asking the question, “How do the tools really work?” Next we ask, “How do we need to adapt and change our behavior to benefit?”

Model-based Software – It’s a Gas Gas Gas

In the previous posts we learned about the Site Parcel’s topology engine. The Site Parcel is node based planar topology that inhales linear data, processes that, and resolves a dynamic model. The duality of the Site Parcel allows it to produce both area creation and grading creation functionality simultaneously.
I enjoy stuff that makes one plus one produce more than two.

A Surface in 3D from Segments

The Site Parcel topology rules are reasonably simple:

  • Only specific linear types of data are allowed.
  • The Site Parcel stores all the submitted segment data separately from the resolved model.
  • Each linear data submission is projected to a model plane.
  • Nodes are generated at linear object’s geometry locations
  • Nodes are generated at all geometry intersections on the plane
  • Only one node occupies a location on the topology (model) plane
  • Only one segment of each type (tangent or curve) may connect any two nodes
  • The nodes and Parcel Segments in the model are inseparably related to one another
  • Parcels are resolved in the model when segments between nodes create a continuous loop or chain of segments.Or you can think about it the other way around -  A Parcel resolves when there is a collection of nodes  with segments between all the pairs of nodes.

Does This Matter?

These picky details matter because otherwise you may end up with a lot of closed polylines (with duplicate segments) inside your Site Parcel models. Old CAD habits can hurt. Duplicate Parcel Segments may matter because Parcel editing (and later annotation processes) becomes a lot more time consuming, confusing, and frustrating when they exist. Civil 3D simply ain’t Land Desktop.

In old CAD based software a LOT was independent from all others. In the model-based world of Civil 3D all Parcels are part of a resolved collection. They are generated, maintained, and resolved inside a Site Parcel collector by its topology engine.

Features Talk to Features and Features Talk to Models

In the same Site Parcel multiple Parcels may share the same Parcel Segments and/or Alignment Features. Feature Lines definitely affect the resultant nodal topology as well. Any and all Parcel Segment input data is potential Breakline data for any Surface(s). Parcel segment input edits maintain a dynamic interaction with that Surface data.

Even though the Site Parcel dynamic model is hidden from us in many ways (something I wish Autodesk would fix by giving the Site Parcel model its own visible components, Style, Label Styles), understanding how it works is critical to our productive use of the tools.

A couple of Parcel posts ago we took a brief peek at some edit tools in the Parcel Segment Ribbon to see the topology engine at work. We also briefly talked about The Parcel Layout toolbar along with some of its current limitations and built-in frustrations.

Parcel Layout Tools

Parcel Layout Toolbar

The basic segment create tools in the Parcel Layout toolbar will only create “Fixed” tangents and “Fixed” curved Parcel Segments at this point in Civil 3D time. No other types of Parcel Segments (rule based and/or tangency constrained segments) are fully supported for Parcel Segments at the moment. The basic tools only require that you set a Site to work in the Create Parcels box.

If you must have complex horizontal control) in your Site Parcel, employ Alignments. Alignments never become Parcel Segments, but they are employed to resolve the model.  There will be more on that later.

Advanced Parcel Tools

There are some more powerful create/edit tools in the Parcel Layout tools despite the limitations. These tools create and special class of tangent Parcel segments. These are fine for most “land chop” (subdivision) and basic grade problems.

The grading flip side of Parcel Segments isn’t so immediately obvious or intuitive at first. Frankly, it’s hard to think 2D and 3D at the same time. Without some acquired experience it’s perhaps difficult at first keep track of the potentially cascading consequences.  
There’s no doubt the AutoCAD Civil 3D Parcel Segment “grading” edit interface can be quirky as well. In fact, the old school and default ACAD edit interface setup makes some very useful things almost impossible.
The Grade and Chop duality of Parcels in AutoCAD Civil 3D is powerful.

Time and Time Again

You may create segments in another existing or even a new Site Parcel when you start any Parcel Layout tools since they each call the Create Parcels box. The Parcel Layout toolbar is dumber than the Alignment toolbar. It doesn’t know where (in what Site) you are working. It doesn’t keep track at all. You must to tell it where to go every single time you employ one of the Parcel Layout tools.

Create Parcels

Watch out! Copy or Move Before You Create

The advanced tools require you to select on screen a resolved Parcel within the selected Site Parcel in the Create Parcels box to do anything. These tools interact with the dynamic model and require a resolved Parcel to function. No resolved Parcel to select – no go on the tool. Arrrgh.

It would be really handy if the Parcel Layout tools showed you what Site Parcel you are editing and allowed you to hop between Site Parcels via a list.
It might be nice if Civil 3D allowed you to copy a selected parcel to another Site Parcel first instead of leaving you in Neverland if you decide to change Site Parcels after you start a tool.
Maybe some time…

The Timely Object Lesson

Before you use Parcel tools Copy the necessary Parcels and therefore the Parcel Segments to the new Site Parcel. That probably means you’ll need Parcel and Parcel Area Label Styles to handle more choices and more Parcels more easily. Get the Style and Label Style tools that do that in InstantOn Basic for AutoCAD Civil 3D 2013. There are even more of them set up for you in Jump Kit.

Attached Segment Power Tools

The advanced Parcel Layout tools create a special class of “attached” tangent segments. Attached segments tools have their own tools menu in the Parcel Layout tools. The attached segments tools only work inside existing resolved Parcels. Their creation process depends on a resolved Parcel.

Attached Segments Menu

Attached Segments employ a Point and Shoot metaphor. From a moveable location on an existing segment, they search outward along a provided (or default perpendicular) bearing to the intersection with another Parcel Segment within the Parcel boundary you choose to work in.
You are establishing a direction for the new segment(s) relative to the current segment at the connection location.

The attached segment will continue to dynamically pole the model for an end segment node location. In other words, the found end of segment node changes to conform to the model.

The Last Pick Shall Be First

The Free Form Create tool allows you to create a single attached segment at a time.

Attached Segments Before

Attached segments can be:

  • Relocated on the segment If the segment is a multi-segment or an Alignment, the location may be relocated anywhere along the entire span of all segments.
  • Created with locations on other attached segments Both the connection and the angular relationships between the group segments are maintained.
  • Graded with the Parcel Segment Elevation EditorThe segment grade breaks are established from the connection location and the other end segment location.
  • May become the basis for Gradings just like a Feature LineI’d suggest you employ this functionality very carefully.

Attached Segments After

In the example before and after pictures above, an arrangement of attached segments is constructed and then the key (alpha) location is moved to a different location on a multi-segment outer boundary. When you do this radical of a Parcel segment move, the Parcel model will often kill and create newly resolved Parcels.

Can you say,

Reactive Attached Grading?

Note the manually set Elevation Point on the “primary” attached segment. It was set in the Elevation Editor from the Parcel Segment Ribbon. The relative relationships to both ends of the alpha (primary) segment are adjusted after the move. The beta (secondary) attached segment location nodes remain grade “bound” to what happens in the alpha (primary) segment.

Varooom. What’s that sound? It’s the sound of speed.
It means managed power in your hands – or not.

Elevation Edit Interface Weirdings

Currently, if you initially select a attached segment the Elevation Editor tools may be greyed out in the Parcel Segment Ribbon’s Edit Elevations panel.

This is an annoying selected object Ribbon bug. There is another possibility.
Everything I’ll talk about for the next few posts (and some in the previous posts) is perhaps an undocumented feature of AutoCAD Civil 3D.
I don’t think so since there is too much useful functionality here. The Ribbon is simply built to respond to the default way AutoCAD Civil 3D is set up and delivered out of the box.

Here’s the how to fix the unable to grade and attached segment problem.
Select a regular Parcel segment and fire the now live Elevation Edit tool.
Pick back over to the attached Parcel segment.
Hit the now live tool to update the Elevation Editor in the Panorama with the current segment’s data.
Viola you are grading with connections - unless you remain old school in your CAD habits that is.

Is <Esc> The Leading Cause of Keyboard Death?

Silly me. I always forget to mention that quick and easy interactive picking from Feature to Feature in AutoCAD Civil 3D is vital to get the work done.

You can only do the steps above if you’ve checked on Shift to Add in your Selection settings. This allows you to change the current selected object in your current selection set without hitting <Esc>.  You DO do that don’t you? Please don’t tell me you still run Civil 3D like it was AutoCAD because it comes set up that way by default?

We can do more than one attached segment at a time. Let’s make our Parcels run in packs like wolves.