Better Best Fit Alignments in 2012

Tags alignment, best fit, horizontal control

AutoCAD Civil 3D allows us to make new and More useful data out of nearly nothing.

This is what better and functional civil engineering design software should do.

The Common "I Need Control" Problem

We need to create some basic and MANAGABLE horizontal and vertical control for a roadway repavement, widening, or pipeline project. All we've got at the moment is some survey collected data or some "data stuff" we can deal with like it was. This fundamental problem isn't confined to classic corridor problems either, but we'll use one here to keep it simple. Here's what we've got.

 Some Survey Data

Normally, I might NEVER produce all this stuff in ONE drawing in a Civil 3D project.
But you've now got a small picture of what a tiny bit of the survey data looks like for couple of miles of roadway.
Typically it's a bunch of collected points and figure data.
All this stuff happened to come in a csv file imported into a Survey Db and represented (barfed) into this drawing from the Db. Ah! The joy of Civil 3D's collectors!
That drawing was created from an InstantOn Basic Survey template. If you own a Jump 2012 product, you got "example data stuff" exactly like the file that did this in the Jump project to play with. Yeah. The "figures" did come from a PNEZD file.

Waaay back in the dark ages (Civil 3D 2011) I posted on the "new" Best Fit Profile tool. The post is worth a read. In AutoCAD Civil 3D 2012, the contents still apply, but now we have More.

We can couple in some of the improved 2012 Survey tools to speed up the control creation and edit process. 

We Want Control

We could use our basic ACAD skills and wing in a fast and dirty pline and convert that to an Alignment Feature. Create Alignment from Objects does that.

Civil 3D 2012 Alignment Creation Tools

Better yet we could employ the Alignment Layout Toolbar tools and the C3D Transparent commands to create a more editable and (in 2012) a more flexible Alignment Feature. Alignment Creation Tools does that.

"Missed By That Much"

Max Smart (of Get Smart fame) knew the drill. Both of these methods rely a lot on our personal judgment about what is important in the data. The methods rely on what we SEE and what we EXPECT to find.

The real world isn't always so cooperative. Here's an Alignment tweaked for the first mile. It looks simple (and in some ways it is), but there some subtle twists, turns and curves even in this pretty straightforward roadway. It wasn't built all at once. Sections of the road weren't even constructed the same way or to the same "standards" either. Sounds like my home town.

A Mile Down the Road

The Create Best Fit Alignment command allows us to assess and peer into selected parts of potential "Control" data via a Standard Engineering Practice methodology called "Best Fit".

For more complex control data problems that can save us time and considerable effort. We can iteratively employ the tool to find a "better" answer faster and in a consistent way.

Best Fit Alignment Data Sources

Potential Best Fit Alignment Data Sources

You should pay attention to ALL of the potential data sources available here. Maybe you are picking up a project where some of the other ACAD sources are available for you to mine for your control. Maybe it's an older LDT/ACAD project that's come back to life; work partially completed by others; or just data you have to work with that came in a "different" CAD form.

What Does Best Fit Want?

Remember the Civil 3D Best Fit is mining all the "data" in anything on the list for point locations.

We'll use a group(s) of Civil 3D Point Features to create an Alignment. As you can see from the list we can't directly employ Survey Figure Features to create a Best Fit Alignment in 2012. 

Beware Your ACAD Think

We could EXPLODE the Figure(s) and create dumb CAD entities to use, but what's the point. By the way, the EXPLODE method can also cause you issues because the interpreted Figure in the Survey Db is NOT the SAME as the ACAD 3Dpolyline that an EXPLODE produces in a drawing. In practice if you use this dumber CAD object approach, you may still have More pline cleanup WORK to perform. Boring and Dumber.

Use The Survey Db Collector

We can get directly to the Survey Db point data connected to any of the Figures anyway.

First, we need to find the Figures with the good stuff. We don't need ANYTHING in a drawing to do this. You can cruise through the Figures in the Survey Db in the Toolspace. A simple Double Click on the Figure in the list does the trick of Zoom to and display it. Way Cool. 

For context's sake here's a selected Figure in the Survey Db (that is NOT in the drawing) displayed over the Best Fit results.

A Figure display but not In the drawing

We DO need to get the Points related to the Figure(s) into the drawing - We need Civil 3D Point Features. 
Technically, we REALLY need one or two Point Groups for Best Fit to process. 
Best Fit tells us this right at the top of the list. So, what's wrong with this picture?

COGO Points are processed by Point Group

How do we get ONLY the Points related to the Figure(s) we want in the Point Groups into the drawing?

Right Click is Your Friend 

This isn't all that obvious because you might not notice that for all things Survey the Right Click menu of any Survey Feature (even individual ones) has a Points>>Insert into Drawing pick. For Figures in AutoCAD Civil 3D 2012 the Right Click menu looks like this.

Figure Right Click menu Insert Into Drawing
Maybe you want an Alignment constructed from the flowline shots made on both sides of the street. No problem. Maybe you want crown shots, roadway paint shots, and selected found monuments. No problem. All you need is to collect them into appropriate Point Groups and feed them to the Best Fit engine.

Always visually review the Regression Analysis for wild hairs. Did you know you can sort the results? Look at the displayed results. Civil 3D has ALREADY built an alignment if it can. Too bad we cannot yet visualize on screen the wild hares.
Read the previous post and or the Help link reference above to find out more about why.

A healthy set of Civil 3D Styles with stable Alignment Label Styles and Sets also significantly reduces your evaluation, editing, and QA time. Good annotation is instantly More informative. Work the Same pays long before you Publish on Demand.

Your Results Should Vary

Civil 3D Best Fit can produce tangent only solutions - Maximum radius for curve detection set to 0. This is a good way to test the tangent based "frame" of the Best Fit solution. It's often worth a testing "view" before you go after more complex solutions.

Without looking for spiral solutions Best Fit will produce simple tangent "Free" curves. These are now much easier to adjust with the new tangency editing tools in 2012.
These new Alignment Feature editing tools made Best Fit much more useful in 2012.
Again one better thing builds yet More on another.    

A Massaged Best Fit Result

More than One

In practice you should probably NEVER run Best Fit just once. Tweaking the Best Fit values around (and/or the point data around) for a 2-3 different runs may produce a result that may reduce your Alignment editing and tuning work significantly.

Isn't That What Best Fit is There For?

I don't know about you? I also use reference tools like Google Earth (a reference images) to keep a big picture view in mind while I focus on creating the Alignment Feature details. Healthy changes of Perspective matters in a good Quality Assurance Process.

A Final Project Alignment Management Tip

Maybe you did or didn't know that Civil 3D 2012 will let you WBLOCK out a Centerline Alignment Feature to a separate drawing so you can have a nice sharable Data reference to work from - almost Right Now. Remember to change the Alignment Feature Style to "Standard" and get the Feature Name "right" too before you do it.

Why would I do that?