Eric D. Colburn, PLS

In today’s AutoCAD Civil 3D Surveying Quick Tips and Tricks I’ll will show you how to Create a Surface From a Point Group. There seems to be a lot of confusion as to how to create a Surface in AutoCAD Civil 3D which is a task you will no doubt use often in your professional land surveying practice.

There are many methods and types of surface data you could use to create a surface in AutoCAD Civil 3D. In this AutoCAD Civil 3D Surveying Quick Tips and Tricks I will concentrate on what I think can become your most used workflow in creating surfaces, and in the next AutoCAD Civil 3D Surveying Quick Tips and Tricks I’ll give you a few extra tips and tricks to automate surface creation, save time, and get your project out the door more quickly.

In general, what we will be doing is:

1. Creating a Point Group for project surface points.
2. Creating a Surface.
3. Using the Point Group to define the Surface.

Even though this is the order I will follow in this AutoCAD Civil 3D Surveying Quick Tips and Tricks, please note that while you do need to have all of the objects defined for this to work, in that, you need to have a Surface and Point Group (and points), the order of populating those objects with data isn’t important. Again, see the next AutoCAD Civil 3D Surveying Quick Tips and Tricks for an in-depth explanation.

And Away We Go ….

1. Create a Point Group for the project surface points. Open the Prospector Tab and expand the Point Groups (I do this just in case the Point Group already exists. If so, skip this step). Right click on Point Groups and select “New“. Name your new Point Group with a nifty descriptive name – I used “Surface Points“. Okay, not so “nifty” but this will make your Point Group very understandable. You can also enter a description if you would like to.

Create Surface Point Group

Now populate the Point Group with point data (you must have points in your AutoCAD Civil 3D drawing). You have many options and filters to choose from, like; other Point Groups, Raw Desc. Matching and Include. I’m going to select the Include Tab and then select the box at the bottom left named “Include All Points“. This will add all of the points in the current AutoCAD Civil 3D drawing to the Surface Points Point Group.

Include All Points in a Point Group

If there are points that you would like to exclude from the Surface, the Exclude Tab at the top of this dialogue box allows you to do just that. So now you have a working list of your topographic survey points in one place (click on the Point List Tab to see the points in this group).

2. Now we will create a Surface. Again, in the Prospector Tab expand Surfaces (Again, only to make sure the Surface doesn’t already exist). If you do not have a Surface defined, then right click while selecting Surfaces and select “Create Surface“. The Create Surface dialogue box opens and you can then edit, or not, the Surface Type, Layer, Name, Description, Style and Render Material. You will see in the image below that I only edited the Surface Name and Description (you will initially see different values, which you should change, if you like).

Create Surface Dialogue

Give your new Surface a handy dandy name and description. I named my new Surface “Existing Conditions” just to be very identifiable within the project and showing absolutely no imagination whatsoever – Go ahead, call your Surface whatever you would like, such as “Fred” or “Gertrude” (live your C3D life on the edge!).

3. Use the Surface Point Group to define the Surface. Now expand your new Surface and then expand Definition. Right click on “Point Group” and select “Add“. In the Points Group dialogue box that opens select your Surface Point Group.

Expanded Surface Menu

Remember that the Point Group I am using is called “Surface Points“, so that’s what I will select.

Select a Surface Point Group

Once done you may need to Update your Surface, or if Automatic Update is on for this Surface, then the Surface will be drawn and updated automatically. This last part sounded silly (imagine that, Automatic Update updates automatically!), but in fact this is a powerful tool to help you when you edit and refine your Surface.

Surface in AutoCAD Civil 3D Drawing

That’s it! Once you know where everything is, and how to setup your Surface Point Group and Surface, it’s very simple. Now, of course, like everything AutoCAD Civil 3D, there are several styles you need setup to match your company standards and represent the surface. I’ll go over them in an upcoming article.

This AutoCAD Civil 3D Surveying Quick Tips and Tricks is brought to you by the Professional Land Surveyor Source, showing you how to Create a Surface From a Point Group in AutoCAD Civil 3D 2010 (or older release) drawing.