- When deciding something linear like a road or a bike path or a utility, you will most likely use an Alignment. An Alignment is a lot like a measuring tape that runs the full length of a design. As an example, when designing a proposed road, the Alignment may represent the Centerline of the pavement. Just like a measuring tape, Alignment distances are labeled at specified increments called Stations. Using these Stations, an engineer can reference any point along a linear design. Many times, Alignments are defined from geometry that was drawn using bearings and tangential arcs, much like what we see onscreen.
Fortunately, Civil 3D includes several tools that make it easy to create this type of line work. In this lesson, we'll explore some of Civil 3D's Line and Curve tools. On my screen is some geometry that could be used as the basis of an Alignment. Our goal is to replicate this geometry. Before we get started, I'm going to make sure that my Dynamic Input is turned On. The toggle is right here in the Status Bar. You can also toggle this On by pressing the F12 key. This will ensure that Command prompts display at the cursor.
To recreate this geometry, I'm going to start by using the Line command. Line can be found in the Draw panel. Now unlike AutoCAD, when I launch Line, it opens up a menu, and you can see all the different ways we can create Lines in Civil 3D. I'm going to use the traditional Create Line method. This is the same tool found in AutoCAD. I will then click to specify the first point onscreen. Now, I would really like to specify this bearing. Using a traditional Line command, that's not an option. I can access a Transparent Tool to give this command more functionality.
I'm going to come over to the Transparent Tools toolbar, and I'll select the second icon down. It represents Bearing Distance. I can now follow the prompts. What Quadrant am I drawing in? Northeast? Southeast? Southwest? I'm drawing the northeast Quadrant, so I will click in this Quadrant to specify it. Next, we'll enter the Bearing. We can see that 79°32'45". Here's how we're going to enter it. I'll type 79.3245. That's considered decimal, degree, minutes, seconds entry.
It's not that I converted the Bearing to a decimal, I just used the decimal to represent the degrees symbol, the next two digits represent the minutes, and then the next two represent the seconds. When finished, I'll press Enter. This locks me to that Bearing, and then I can enter the Distance. I'll type 150, and I'll press Enter. As you can see, I'm still in the command, and I can start working on my next segment. This is a great tool to use if you're working your way around a property boundary from a legal description. For right now, I'm going to cancel out of the command. I'll press the Esc key one time to cancel out of the Transparent Tool.
I'll press it again to cancel out of the Line command. Next, we'll add this curve. If we come up to the Draw panel, you'll find that Civil 3D includes a collection of specialized Curve tools. I'm going to use this one, Create Curve from End of Object. This allows us to draw a tangential arc from the end of a Line or another arc. I'll select my object closest to the end point I want to connect to. In this case, I know the Radius, so I'll press Enter to accept that as the default. We would use the Point option to select the end point of the chord.
I will then enter the Radius, I'm going to type 200, and I'll press Enter. Now, what else do I know about this Curve? You can see there are several options. Length happens to be the default. I'm going to press Enter to accept that, and I'll type in a curve length of 100, and I'll press Enter. The trick to using this tool is the way you enter the Radius. Since I entered a positive Radius, my Curve travels in a clockwise direction. If I entered a negative Radius, the arc will be drawn counterclockwise. Let's create the next Curve.
I'm going to go back to the Curve menu and while I could use the "from End of Object" method, let's take a look at this one, Create Reverse or Compound Curve. I will then click nearest the end I want to connect to. This is a Reverse Curve. What's my Radius? 300. I don't have to worry about positive or negative here. It knows it's a Reverse Curve. What else do I know about the Curve? Length happens to be the default so I'll press Enter to accept it, and the curve length is 175. Finally, we'll add this remaining straight segment.
Knowing what we know now, I could launch the Line command and snap to the end point here, and then I could use the Bearing Distance Transparent Tool to enter these values. Let's try something else. I'm going to come back to the Line menu, and then I'll come down and choose Create Line from End of Object. I have to apologize, my screen resolution isn't tall enough to allow us to see that option here in the menu. That's all right, you go ahead and select that one, Create Line from End of Object. I'm going to click on screen and I'll come down to the Command line, and I'll launch the Command manually.
I'll just type linefrom, and then I'll grab it from the menu here. I will then select nearest the end point I want to connect to, and I don't have to enter the Bearing, it's going to construct the line tangent to that arc. All I have to do is enter the distance. I'll type 65. Now that I'm finished, let's test this geometry to see how well we did. I'll do that by adding some dimensions. To dimension a geometry, I'm going to come up to the Annotate tab, and then down at the far left side, I'll click this large price tag icon. This brings up the Add Labels dialog box.
From here I can select the type of Feature that I'm labeling. I'll choose Line and Curve. Next, I can choose the Label type. We're labeling these objects one at a time so Single Segment is perfect. For Line label style, I'll make sure this is set to Bearing over Distance, and for Curve label style, we'll use Distance over Radius. I will then click Add, and I'll click this segment, and this one, this one, and this one. When I'm finished, I'll press Esc, we'll close the Add Labels dialog box, and then I'll return to the Home tab.
Using Civil 3D's Line and Curve tools, we can quickly and accurately create the geometry to be used as an Alignment. If you have some time, try exploring some of the other tools in the Line and Curve menus. I'm sure you'll find several you can use in your daily workflow.
- Exploring the design data in drawings
- Creating, connecting, and grouping points
- Customizing label styles
- Defining existing ground surfaces
- Designing horizontal alignments
- Controlling alignment properties
- Creating profiles and profile views
- Sharing design data
- Creating and managing parcels
- Building assemblies
- Modeling advanced roadways
- Defining gravity-based pipe and pressure pipe networks
- Creating sections and section views
- Analyzing designs
- Generating plan sheets
Skill Level Intermediate
AutoCAD Tips, Tricks, & Industry Secretswith Jeff Bartels3h 48m Intermediate
AutoCAD 2015 Essential Trainingwith Scott Onstott8h 35m Beginner
1. Laying the Foundation
2. Creating and Managing Points
3. Defining Existing Ground Surfaces
4. Designing Horizontal Alignments
5. Creating Profiles and Profile Views
6. Sharing Design Data between Drawings
7. Creating and Managing Parcels
8. Creating Basic Roadway Models
9. Exploring Advanced Roadway Modeling Concepts
10. Modeling Gravity-Based Pipe Networks
11. Modeling Pressure Pipe Networks
12. Managing Sample Lines
13. Creating Sections and Section Views
14. Exploring Grading Tools
15. Analyzing Designs
Using the Inquiry Tool6m 7s
16. Generating Plan Sheets
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