There will be times when the drawing necessary for a project has already been created and you need to import it. In this case you will be using an AutoCAD DWG file that consists of contour lines needed to create the terrain. The drawing and aerial photograph of the site have been provided by the Marin County Department of Public Works.
Note: The drawing used here is a simplified version of the real topographic file. It is a “lightweight” file so it is easier to learn from. In the real world, these type of files will take a longer time to open and navigate.
Import the AutoCAD file:
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In the Select File to Import dialog, change the Files of Type to All formats and navigate to the \tutorials\land directory on your local hard disk.
You could also change the Files of Type to DWG rather than All formats, either method will work in this case.
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Highlight 3hills.dwg and click Open.
The AutoCAD DWG/DXF Import Options dialog appears. Here you can make adjustments and set options for the file you are importing. In this case you don't need to make any changes, so just click OK.
Navigate the viewport:
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In the viewport navigation controls, click the Zoom button. Try to zoom into the viewport.
You can also zoom with the wheel of your mouse, if you have a middle wheel. If you don't have a wheel, hold down Ctrl+Alt+middle-mouse button to zoom instantly.
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In the viewport navigation controls, click Arc Rotate Selected.
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Position the mouse cursor inside the yellow circle and then drag to rotate the viewport.
In the illustration, you can see the three hills that compose the building site and a yellow object indicating north. You can also see the "blank spots" in the contour where the buildings are today.
The topographic survey information comes from after the building was built.
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Zoom and rotate so you can see the hills from ground level. This will give you an idea of the profiles of the hills.
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Press Shift+Z on the keyboard to undo the viewport rotation.
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Repeatedly press Shift+Z to undo viewport changes until you are back to a three-quarters view from above the three hills.
Create the contour lines:
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When you do your own projects, you might not have access to a DWG contour line file, like this one. It's not too hard to make your own. You can load an aerial photo of the site into the Top viewport as a viewport background, then draw contour lines using the Autodesk VIZ Line tool. After you have drawn the contour lines you can raise them up off the ground by typing the elevation into the Z field of the Coordinate display. You can get this elevation information from survey data. This is a long and tedious process, so we're not asking you to do this as part of this tutorial. Instead we provide you with a file of contour lines at the correct elevations.