Join Josh Modglin for an in-depth discussion in this video Creating surfaces: Point group definition, part of AutoCAD Civil 3D Essential Training.
- [Instructor] Now that we've learned what a surface is in Civil 3D, the points, and then the triangles that connect the points, let's go ahead and create a surface using Civil 3D points. We're going to go to our drawing, and our exercises, 0402, Surface Points, and you see within this drawing, we have many Civil 3D points already in the drawing. So what we're going to do, we're going to create a surface and use those points. You can create a surface from the Home ribbon, Create Ground, Add a Panel, Choose Surfaces, and select Create Surface.
We're going to create a surface of the existing ground, so we're going to name our surface Existing Ground. It's always good to put a good description in here as well. Information of where the surface came from, and maybe even the date of where that information came from. But notice that the surface layer is already set for us, as well as the style. The surface layer is being set from our object layer settings, and then our style is coming from our feature settings, Default Styles. So it's good again to remind ourselves that having those settings in place speeds up the work quickly by only having to just enter a name.
Everything else is ready to go. We click OK. We go to Prospector here, under Surfaces, we see our new surface has been created. Now it doesn't show up in the drawing because we haven't provided any points. Without any points there's no triangles, without triangles you have no mall. So let's add those points to our surface. So Existing Ground, I expand that out. I expand out Definition. Here's a list of all the items that really play into defining our triangles.
So what points and the information we can get those points from is connected with our point files, point groups, even getting information from the survey data base, or survey figures. We can even provide drawing objects, and it will read the objects and the coordinates of start points and end points and so forth, of AutoCAD objects to derive those points for the surface. Additionally, we'll provide information that will impact the triangles as well.
Now to begin with, let's go ahead and add our point group to create our surface. I'm going to right-click and choose Add, and there's only one point group in the drawing, AllPoints. This is a good reminder as well. This is another example where point groups would be very powerful. We could create a point group that has nothing to do with visual control of our points, but contains all of the points that have vertical data. Data that would be useful for creating a surface. Now we could name that point group just along that line of surface data.
That way, we're not containing or grabbing all of the points, we're just grabbing the points that are specific to creating the surface. So we see the power point groups in many different ways. But we're going to go ahead and use AllPoints point group. Click OK. Now because it had the points, it was able to create the triangles, The triangles of course, give us the ability to display contours. So we have a good start here. We do have a bit of a spike, and we see why. We have elevations of 773 on one side, 779 on another, and 700s, 770s really, seem to be the general elevation of the area.
And right in the middle, we have an elevation of zero on the point. We're not going to assume it's a bad shot, it could be a point that's just connected with a property boundary or something similar, where vertical data wasn't important. So we can't delete the point. So we could create a point group, and not have that point included in that point group. Another approach is by making some adjustments to the surface properties. I'm going to right-click on my surface in Prospector, and choose Surface Properties.
Now from the Surface Properties, we're going to go to the Definition tab. In the Definition tab are the abilities to control options to define the surface. Some options are, Exclude elevations less than, Exclude elevations greater than, Control the maximum angle of your triangles, and so forth. We're going to chose Exclude elevations that are less than, and then we're going to send an elevation in here of 10. We have elevations in the 770s. If there's any elevations that are included that are 10 or below, chances are they're arbitrary elevations and don't belong.
So we're pretty comfortable with that. We click OK, it asks us to Rebuild the surface, and now this point is completely ignored. Although it's in the point group that we've entered, it has chosen to ignore that because of some build options in our surface properties. Now here's a good start, but there's more to it than just adding the points, we have to now also control the direction of the triangles.
This course gets you up and running with AutoCAD Civil 3D. First, instructor Josh Modglin shows how to model a surface, lay out parcels, and design geometry, including the making of horizontal alignments and vertical profiles. Next, Josh demonstrates how to create corridors, cross sections, pipe networks, and pressure networks. Then, he covers working with feature lines and grading objects, and how to share your data. He wraps up by providing an overview of plan production tools.
- Navigating the Civil 3D interface
- Using point groups and description keys
- Importing survey data
- Managing figures
- Creating and analyzing surfaces
- Creating parcels
- Working with alignments
- Working with profiles and profile views
- Working with assemblies and subassemblies
- Creating Basic and Advanced Corridors
- Using an Intersection Object
- Making sample lines, cross sections, and section views
- Creating a pipe network
- Understanding pressure parts
- Creating and editing feature lines
- Creating and editing grading objects
- Sharing and referencing data
Skill Level Beginner
Some of the exercise files do not properly function.
This course was built to work with the latest release of AutoCAD Civil 3D. If you are not running AutoCAD Civil 3D 2018 there are some exercise files that will not work for you.