You can use just about any existing 2D contour drawing to build a 3D contoured site model in DesignWorkshop. This tutorial shows how to build a contoured site model working from a pixel image of a contour drawing.
If your starting point is a drawing on paper, you would start by scanning the drawing, which will give you a pixel image of the drawing. Save this in PICT format so it can be opened in DesignWorkshop as a background image. Any background image can be traced accurately in the plan or elevation views.
Alternatively, if your starting point is a computer drawing in DXF, object PICT, or PowerCADD Scaled PICT format, you can import the drawing into the 3D modeling space directly, instead of scanning first. As a result, you can work with the drawing directly in perspective as well as in plan view.
1. To follow along with this tutorial exactly, you can use the file name Contours.pict on the DesignWorkshop CD-ROM. It can be found in the Accessories:Backgrounds folder.
2. Once you have a PICT file of the contour drawing of your site go to plan view in DesignWorkshop. In the File menu go to Background > Open.... Select the PICT you are going to use and it shows up as a background image. Every 20 pixels in the PICT will be scaled to one working unit in DesignWorkshop, by default this means there will be 20 pixels per feet. With this knowledge you can scale your PICT before opening it as a background. In this tutorial we did not scale the PICT, we will scale the entire model towards the end. Either method is OK.
3. Now you'll want to zoom in so you see the background in its entirety and not much else. Use to 2D zoom tool in the lower left corner of the tool pallette to do this. You'll probably want a finer grid snap than 0.5 feet, so set this to 0.25 feet by selecting Preferences > Snap Grid from the Layout menu.
4. Now you want to find the corner of the contour drawing with the highest elevation. In our case, this is the upper right corner. Most of the contour lines we make will begin from this corner. Now with the polyline tool, start at the highest corner and trace around the nearest contour line making a closed loop around the highest corner. You are making polyline "pancakes" which will later be extruded upwards so you'll end up with a series of layers forming your contour model. When this polyline is finished continue to the next contour line. Again starting at the highest corner and tracing the contour. Continue the process for each contour line.
5. Some of the contours on the drawing are likely to be different than they are drawn. For example we are making a flat area for the footprint of the building. So when a contour reaches the edge of the building location we are wrapping it around where the building will go and continuing it on the other side. To clarify this we have used the pencil tool to show where the contour lines are going in our model.
6. Just continue tracing the contours as polylines, always starting and finishing each polyline at the highest corner.
7. Now we'll make a polyline tracing the building footprint.
8. In this contour drawing we know the size of the lot, and the property lines are drawn on the map, so for scaling later, we'll make a polyline which traces the property line.
9. Now we'll go back and trace a couple contours that we missed. In each of the lower corners is a contour that we couldn't trace from the highest corner because their "pancake" never meets with that corner.