From the course: Autodesk Civil 3D 2021 Essential Training

Understand grading - AutoCAD Civil 3D Tutorial

From the course: Autodesk Civil 3D 2021 Essential Training

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Understand grading

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- [Instructor] In this chapter, we're going to talk about redesigning the terrain of our project, also known as grading. Before we dig in, pun totally intended, let's discuss the basic concepts of grading. You might be thinking that we've already modified the terrain in our project using the corridor. And if you are thinking that, that's totally true. I guess, technically that is a form of grading, but we simply don't refer to it that way. When we talk about grading, we're not referring to the long linear terrain shaping, typically done with corridors. Instead, we're talking about isolated areas like a residential lot, a pond, or a parking lot. In fact, we've got a residential lot, or two of them here represented as well as a pond in 2D and 3D. These are all examples of areas where we perform grading in Civil 3D. Now the key object at play with grading is the surface, which you learned about in chapter four. And in that chapter, you learn how to use surfaces to define the existing conditions of the project. In this chapter, we're going to use surfaces to define the proposed conditions. How we want the project to look when it's done. You may also recall that breaklines are a key contributor to the definition of a surface. In chapter four, breaklines were drawn through points collected in the field. In this chapter, when you're doing grading, you're going to draw those feature lines based on how you want the design to be. And as you'll learn, Civil 3D has some powerful tools to make that easier for you. So that's what grading is. Coming up with the proposed ground surface, which defines the changes that you're going to make to the existing ground surface, before and after, if you will. Okay. So that's some of the basic philosophy behind grading. With that, you're now ready to go to the next video and talk about the first key Civil 3D object that will help you get grading done, the feature line.

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