Importing Terrain

Learn how to import, in just a few minutes, Terrain into your AutoCAD design, create contour lines and speed up your design process!

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Terrain models play an essential role in the planning and design phases. They help engineers to improve their project’s precision and reduce costs. Plex.Earth offers access to high-quality terrain data in a very short time and this is why it has become a necessary design tool. Below, all the required steps are presented on how to import DTMs, easily and quickly, into AutoCAD. Moreover, some more advanced settings will be explained, as well as the ability to create contour lines.

Step 1: The "Terrain" Tab

Step 2: Terrain Providers

Step 3: Customization and Quality Settings (Optional)

Step 4: Import Methods

Step 5: Terrain Types

Step 6: Creating Contours

If you don't already have Plex.Earth, download your fully-functional weekly trial from here.

Step 1: The "Terrain" Tab

In order to begin your import, go to the "Terrain" panel, from the Plex.Earth’s tab. Click on the "Import Terrain" and the "Terrain Dialog Box" will pop up.

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* Before beginning with this tutorial, make sure that you have georeferenced your drawing.

Step 2: Terrain Providers

In the "Terrain Dialog Box", you can choose between our offered providers:

  1. Google Earth
  2. Bing Maps
  3. World Terrain Dataset

Just click on the icon of the provider you are interested in.

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Step 3: Customization and Quality Settings (Optional)

After choosing the preferred provider, you may want to customize your settings and change the quality of the terrain, according to your needs.

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Clicking on "Quality" in the World Terrain Dataset, lets you choose between predefined quality levels.

Similarly, in Bing Maps, you can define numerically the desired grid space.

Finally, on Google Earth, the following window will pop up:

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When having "Automatic Mesh Calculation" activated, Plex.Earth will create a terrain based on about 4,500 points. This is recommended for fast and relatively accurate results.

However, you can also define your own resolution in the "Custom resolution" box. For example, considering the value from the picture above, points for every 100 ft (approximately 30m) will be imported for our Terrain. In order to set custom values, just untick the "Automatic Mesh Calculation".

Tip: In most areas, the underlying Google Earth terrain model is based on a sampling of about, at best, 100 ft (30m). Therefore, setting a quality less than that, will not result in a more detailed model in AutoCAD, while delaying the import process. 

The exception to the rule of thumb above is areas where Google Earth offers its vivid, photorealistic imagery. There, you can set the grid spacing even to a few feet (like 3-5ft), while also enabling the "Consider 3D Buildings elevation" option to get a quite good point cloud dataset of the surroundings. At the end of this article, you will find a ΚΜΖ showing an area including detailed 3D buildings in Google Earth.

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Keep in mind that the "Customize" option is available only for Google Earth. When clicking on it, the following window appears:

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For faster performance, it is suggested the Capturing Eye Altitude be optimized by Plex.Earth. However, a custom eye-altitude can also be set. Setting a low eye altitude can slightly increase the accuracy of points’ elevation obtained for a specific area but keep in mind that a very low eye-altitude may cause errors if it is lower than the altitude of the points obtained. 

Here, you can also choose if you want or not to restore the area you are watching in Google Earth, after finishing the import, as the Terrain Import process may move the area in Google Earth (restore is pre-selected). 

Finally, due to a memory limitation on behalf of Google Earth, for very big Terrain Imports, Google Earth may have to restart a number of times in order to fetch the necessary elevation points.. Enabling the fully automated capturing procedure automates the required restarts so that the user does not have to close and reopen the Google Earth window manually each time.

For more Options about terrain Customisation check at the end of this article

Step 4: Import Methods

In the next step, we have to define the terrain import method, so as Plex.Earth 4 to know which area to cover in our drawing. The provided options are three.

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  • By Google Earth View: The imported terrain corresponds to the area that is currently shown in Google Earth’s window
  • By Area: A polyline or a window will outline the area in which our terrain will be imported.
  • By Path: Terrain is imported alongside a specified centerline polyline and for a particular swath width that the user manually defines (you can see a case option about this import method here)

Keep in mind that Plex.Earth 4 always keeps your last settings, so you do not have to define them each time you import Terrain. So, if you don’t want to make any changes, you can skip the "Terrain Dialog Box" and directly choose your import method from the following buttons in the AutoCAD panel.

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Step 5: Terrain Types

After choosing the import method, you will then have to choose the type of terrain and whether this will be a Terrain Mesh or a Terrain with 3D Imagery. In the first option, a mesh terrain object will be created, whilst with the second option, Plex.Earth will automatically create a 3D image for the area (for more details about the 3D images, click here). 

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You can always save your choice in this step and skip it in the future, by ticking the “Remember my choice” option.

After selecting the type, the terrain import process will begin.

Remember that if you have chosen Google Earth as the provider, it may automatically restart a few times, as explained above.

Step 6: Creating Contours

In this final step, if you have selected to work with a Terrain Mesh and before the process is finished, Plex.Earth 4 will ask if you want to create contour lines.

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Again, you can select Plex.Earth 4 to remember your choice, in order to skip this step in the future. You can always change your selection in the future, as described in the next section of this tutorial.

More about creating contour lines with Plex.Earth 4, here

Conclusion

After completing the steps above, the final result, depending on the terrain type, will be one of the following: 

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You can see all the above steps, in detail, for importing a Terrain Mesh, in the video below:

Now that Plex.Earth created the surface model, the engineer can proceed to the design process with greater confidence. Actually, he will be able to analyze all the important aspects of the project’s site (bumps, dips, channels, etc) with just a few clicks and from the convenience of his own office. Of course, the terrain can also be imported in other design software, like Civil3D, thus making the preliminary design and the conceptual stage more targeted, more fast and much cheaper.

Feel free to contact us at support@plexscape.com for any questions you may have. Start your free trial today!

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* Terrain Options Dialog Box *

You can further customize the settings of the terrain imports from the Terrain Options Dialog box. Just click on the "Options" button on the down-right corner of the window, or type "PXC_OPTIONS_TERRAIN" in the command line of AutoCAD.

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This option window will pop up:

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Now, in the General tab, you will be able to define the desired mesh types. You can choose between these types: 

  • Automatic: Plex.Earth 4 automatically applies the mesh type. If you are using AutoCAD that would be a mesh object when using Civil 3D will give a Civil 3D Surface.
  • Mesh: Results in a mesh object at all case
  • Polyface: Imports a Polyface Mesh
  • Points: Imports only points
  • Contours: Imports only Contour lines
  • Civil 3D Surface: Imports surface recognizable from Civil 3D. If it is chosen in AutoCAD, it will return a mesh object

Keep in mind that the above selection applies only when you choose Terrain Mesh on Step 5. Terrain with 3D Imagery is always imported as a mesh object.

Finally, you will also be able to choose if you want automatic creation of contour lines, along with your Terrain Mesh import.

 

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