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Michael Kinnear/4 min read

Creating and Organizing Grading Groups in Civil 3D

Grading Group Concepts

Group Definition

Bundles related grading objects for collective control.

Quantity Reporting

Calculate total cut/fill across all members of a group.

Surface Generation

Create a single surface from all grading in the group.

Naming

Names like 'Pad A Grading' or 'Detention Pond' for clarity.

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This Civil 3D tutorial walks through creating and organizing grading groups in civil 3d, covering essential tools and techniques for your projects.

Now that we've prepped our parcels with their specific pads, we're ready to start talking about grading, grading objects, and grading groups. Inside of Civil 3D, grading has its own dropdown.

It's up here in the Home tab of the Ribbon bar, right under Grading. So there are three options inside of Grading. We have the option for Grading Creation Tools, Create Grading Infill, and Create Grading Groups.

All of your Grading entities inside of Civil 3D need to be organized inside of Grading Groups. And so even though you can click on Create Grade or Grading Creation Tools, and then if you don't have a Grading Group, Civil 3D will prompt you to create one, I think it's good practice.

If you intend to start working on a Grading Group that hasn't been created yet, you should go ahead and create the Grading Group before you start working in the Grading Creation Tools. So I'm gonna go ahead and select Create Grading Group. From here, I'm gonna be given the option of what I want the name for the Grading Group to be.

All of these Grading entities are gonna be associated with my Dev Main corridor. So I'm gonna go ahead and call this DevMainGrad. From here, I could give it a description.

I'm not gonna go ahead and do that. I'm gonna move on to the next option, which is automatic surface creation. Whether or not you check this box, Civil 3D can or won't create an automatic surface based on your Grading Groups.

I'm gonna go ahead and check it to have it create an automatic surface. I'm gonna go ahead and use the group name, DevMainGrad, as my surface name. I'm gonna specify the surface style as Design Topo.

And then we have these options of tessellation spacing and tessellation angle. Tessellation spacing and tessellation angle are basically how Civil 3D will interpret your Grading Group into a surface. Tessellation spacing sets how many breaklines are placed into your surface based on your Grading Group, or how few of them are placed in it, or how far apart they’re spaced.

The important thing to note is that the smaller the number you choose for tessellation spacing and tessellation angle, the more detailed your surface will be. And the larger the spacing or the larger the angle, the less detailed your surface will be. I am fine with 10 feet for the tessellation spacing and three degrees for the tessellation angle.

So I'm gonna go ahead and leave these as they are. I am not going to check this volume-based surface option. Civil 3D can create a volume-based surface for you.

If you select this option, you would set the base surface for your volume-based surface. I am not going to create that. So I'm gonna go ahead and leave it unchecked and click OK.

Civil 3D is now going to prompt me to create my surface. Because I already prompted it to automatically create this surface, it has now filled in the name of DevMainGrad. It has also set the style as Design Topo, as I indicated in the previous window.

So I'm gonna go ahead and click OK. What Civil 3D has now done is it has created my DevMainGrad surface. It has also created my DevMainGrad Grading Group.

If you don't have these expanded out, Grading Groups are found under Sites. They're found under the specific sites, so under our DevMain, and then under Grading Groups. Same thing with the surface.

It's under Surfaces, and then here’s our DevMainGrad surface that’s being built from our DevMainGrad Grading Group. So what I'm gonna go ahead and do now is save this drawing, and then I'll meet you in the next video.