Join Eric Chappell for an in-depth discussion in this video Use the line and curve commands, part of Cert Prep: AutoCAD Civil 3D Certified Professional.
- [Narrator] Civil Engineers and surveyors have unique ways of drawing things in certain instances. In this video, let's take a look at some of the specialized Line and Curve commands that are offered up by Civil 3D. Now we're not talking about AutoCAD Line and Curve commands. In fact, if we go to the Home tab of the ribbon, we see this Draw panel and on the Draw panel we see a lot of different drawing commands. And we're interested in this first column which are commands that are specialized for Civil engineers and surveyors.
If we look at the middle column for example, we just see your standard AutoCAD Arch commands. And Circle commands and so on. Here's the Poly Line command Rectangle and so on. But in this column we see some line commands that may look a bit odd if you're new to Civil 3D. Things like Draw Line by Point # Range or by Azimuth and we see the list goes on. And also with Curves, we'll see some unique ways to approach Curves.
Create Curves Between Two Lines. Well, isn't that just a Fill It command? Not really, we'll see how it works in just a moment. And some other specialized commands as well. And then in the middle, we see this Best Fit concept where we're creating a line based on regression or a curve as well, a curve or an arch based on a best fit solution between a bunch of points. And we see this commonly in surveying especially because we're using field located points which aren't perfect in accuracy to maybe represent what should be a straight line, like a property line, a fence line, center line of a road, which in the case of a road center line may include archs as well.
And again, we're out in the field locating points along these objects and that introduces some error and these commands help Civil 3D to approximate the best fit, line or arch through the points. So let's go to the basics first. Just some line commands, now I can't demonstrate all of these to you because the video would be too long. But let's take a look at some of the simple ones or common ones. First of all, we just have Create Line at the top which is your standard AutoCAD Line command.
You simply pick points and a line is created. Each segment being an individual line object. So what's the deal with these point oriented line commands? Here we see a Line by Point # Range. Well, let's see, if I launch this command, notice I have points one through five on the screen, and if I just enter 1-5, it will draw a series of line segments using all of the points between one and five. And it'll even prompt me for the next set of points, I can just press Escape a few times to exit the command.
And here we see we've got individual line segments and all five of the points have been used. I'll just go ahead and undo that. Now maybe I want to draw my line by picking the points graphically. And that's the Create Line by Point Object. And maybe I only want to use points one, three and five. So the range idea doesn't work very well. And if I'm zoomed way back, I don't want to have to worry about snapping to the exact node of the points. So with this command, I can click way out here in the letter E and here I can click on the number three.
And here I can click on the red x. And as long as I click somewhere on the point object, it will snap to the correct location for the point. So you can see how these commands, you're starting to get a sense of how these commands are specifically designed for surveyors and Civil engineers. Let's take a look at a few more. Line by Bearing, let's say I've got a legal description of a parcel boundary and I need to draw by bearing and distance, that's what this command is all about. When I launch the command, it asks me for a start point and I pick one, next it asks me for a quadrant.
What could that be, if I look at the command line, we see that Northeast is one, Southeast is two, Southwest is three and Northwest is four. It allows me to define a bearing in two parts, kind of the outside first, the beginning letter and the ending letter and then the angle in between. So let's say I want to specify a bearing of North 45 degrees east, well, first I do the Northeast part. And type in a one and then I provide the bearing which I said was 45 degrees.
Notice I can enter in degrees, minutes and seconds. Let's say I wanted to do 45 degrees, 15 minutes, 12 seconds. That would just be 45.1512 and I know that looks like a decimal degree but it actually is a way of specifying a bearing in Civil 3D to make it easy. But still allowing you to express your bearings in degrees, minutes and seconds which is the common way, again, for a civil engineer or surveyor to do it. So I'll press enter, now it asks me for a distance or length of my line, let's type in 500 and press enter.
So now I've got a line on the screen that is 500 feet long in this case because I'm in imperial units and the bearing was 45 degrees, 15 minutes, 12 seconds Northeast. So North 45 degrees, 15 minutes, 12 seconds east. That's a Line by Bearing and that's a very commonly used command. We see Line by Deflection, Station Offset, of course you'll need an Alignment to do that. We can create a line from the end of an object which is handy if we have an arch.
We can create a line that's tangent from a point and so on. So these again, are variations on the different line and arch, or the different line drafting tools in AutoCAD that have a spin put on them for civil engineers and surveyors. Let's look at the Curve commands. Let's see, Create Curve between Two Lines. How is this different than a Fill It? Well, I'll launch the command and let's select these two white lines in the drawing. And this is where you see the difference. There are many more options here than you would see with the Fill It command and they include options like Cord and Mid-Ordinate and Tangent which aren't necessarily options that you would see with the Fill It command.
So I can specify a curve based on it's length, the length of the curve itself which is a common way to do it. I'll type L for length and 200 and that gives me a 200 length curve, not radius, which is typically what we do with Fill It. But other than that, it behaves like a Fill It. Let's undo that command and let's take a look at Create Curve on Two Lines. I'll pick the first line, the second line. I'll do length, once again and 200, once again.
And what it does is it places the curve but it does it without modifying the Tangents. So now I have three separate objects. And there are ways to do this with the Fill It command but these tend to be more straightforward and oriented in a way that a civil engineer or surveyor would expect them to be. So again, not enough time to go through every single command here but another handy one here, Create Curve From End of Object, if I launch this command, pick a line for instance and I'll define my curve by radius and I'll say 250 feet.
And then I'll give it a Cord length of 500 feet. There you can see the arch or the curve was created tangent to the line before it using the parameters that I specified. And going back a bit, we can go to Line again and do a similar thing, Line From End of Object. And I find this very handy and I'll just give it a distance of 100 feet, it'll automatically make that little segment tangent to the curve before it and drawn from the end of it. I'm going to erase all of this just to kind of clear the screen a bit so that we can talk about Best Fit.
I'm gonna create a Best Fit Line using all five of these COGO points. I'll click okay and simply select the points. And as I pick each point, Civil 3D is on the fly, in real time, calculating the Best Fit Line through those five points. If I press Enter, it even gives me a regression analysis with the ability to actually modify the results in this panorama view here. And you can see that Regression Data is the name of the tab.
So I can even do that, similarly I could do something with a Best Fit Arch or even a Paradala. So working with survey points, typically we're trying to find the best solution through a series of points that are typically field located. And because of that there's an error involved and we have to find the best fit. So there you have it, that's how Civil 3D provides specialized ways for civil engineers and surveyors to draw lines and curves. My advice is to study and practice each of these commands in preparation for the certification exam.
This course isn't designed to teach you the basics, but to help you refresh your Civil 3D skills and prepare for the exam topics and format. Once you're finished with the course, you can feel confident taking the AutoCAD Civil 3D Certified Professional exam.
- Creating and using styles
- Using line, curve, and point creation commands
- Creating and editing surfaces
- Annotating parcels
- Creating alignments
- Designing profiles and profile views
- Creating sections and section views
- Managing and sharing data
- Producing plan documentation such as sheet sets