CHAPTER 18
Site and Topography

You might be asking yourself if there is a fourth Revit. No. It would be nice if there was a “Revit Civil,” but there isn’t such a thing. So, we’re left to our own devices when it comes to adding a site to a model. This is fine, because in many cases, Revit is well equipped to take on the challenge. Unfortunately, also in many cases Revit is dependent on AutoCAD or MicroStation to provide a real-case scenario for a site that can be imported (similar to importing a plan or a detail). Fortunately, Revit provides tools to add a topographic surface to an imported CAD site.

Adding a site within Revit
Splitting the surface
Creating subregions
Adding site components
Adding building pads to displace earth
Adding a property line
Creating a toposurface by instance
Creating a graded region

Adding a Site within Revit

To get started, let’s do something easy, and then migrate into the more difficult areas such as importing a CAD file. The first item you’ll tackle will be to start a site using datum points that you’ll manually pick using the Toposurface function on the Ribbon’s Massing & Site tab.

Let’s get cracking. To get started, open the model you’ve been working on. If you missed the previous chapter, go to the book’s web page at www.sybex.com/go/revit2012ner. From there, you can browse to Chapter 18 and find the file called NER-29.rvt.

The objective of the next procedure is to add a topographical surface by choosing datum points and elevations. Follow along:

1. In the Project Browser, find the floor plan called Site, and open it.
2. Type VG for Visibility Graphics.
3. On the Annotation Categories tab, deselect Callouts, Elevations, Grids, Matchlines, and Sections, and click OK.
4. On the Massing & Site tab, click the Toposurface button, as shown in Figure 18.1.

FIGURE 18.1 Click the Toposurface button on the Massing & Site tab of the Ribbon.
5. On the Options bar, set the elevation to -2´–6˝ (-750mm) (that’s negative 2´–6˝ (-750mm)).
6. Pick points in a pattern to the right half of the building, as shown in Figure 18.2.

NOTE

Notice that after you click the Toposurface button, Revit launches Sketch Mode. The Place Point button is selected by default in Toposurface Sketch Mode.

FIGURE 18.2 Adding the first contours
7. With the Place Point command still running, set Elevation on the Options bar to -1´–0˝ (-300mm).
8. Pick five or six points in a line, similar to Figure 18.3.
9. With the Place Point command still running, set Elevation on the Options bar to 2´ (600mm).
10. Add a third contour line to the left of the second, as shown in Figure 18.4.
11. Click Finish Surface (the green checkmark).
12. Select the topographical surface; then, in the Properties dialog, click into the Material field, and click the […] button.
13. Choose Site – Grass from the Materials list, and click OK.
14. Go to a 3D view and check out your site, as shown in Figure 18.5.

Next, let’s see how you can modify a site after you create it. You’ll have to deal with the fact that the ramps at the west entry are buried in your site now.

f1803.eps — **FIGURE 18.3** Adding the second contour to the site

f1804.eps — **FIGURE 18.4** Adding the third set of contours

f1805.tif — **FIGURE 18.5** The toposurface

Modifying a Toposurface

Because you must always make modifications to a toposurface, you need to learn how to do so. The method is basic. Select the site, click Edit, and away you go!

The objective of the next procedure is to modify the Toposurface to allow for the ramps to land on earth. Follow these steps:

1. Go back to the Site plan.
2. Set Visual Style to Wireframe.
3. Zoom in on the west wing area where the slanted curtain wall resides, as shown in Figure 18.6.
4. Select the site (you may have to find an edge).
5. On the Modify | Topography tab, click Edit Surface.
6. On the Tools panel, click the Place Point button.
7. On the Options bar, set Elevation to 0.
8. Pick five points (see Figure 18.6).

FIGURE 18.6 Adding the 0 elevation points
9. Click Finish Surface on the Surface panel.
10. Change Visual Style to Shaded.
11. Go to a 3D view to make sure it looks correct.
12. Save the model.

Excellent! You’re getting the hang of this. Next, you need to create some raised areas (small hills) where you can eventually add some plantings and different materials. The problem is, to create a small hill, you need the site to sharply rise to the new elevation. To achieve this, you have to physically split the surface.

Splitting the Surface

When you need to make a drastic change to the surface’s elevation without influencing the rest of the site, you must split the surface. Just to warn you up front, be deliberate about when and where you do this, because you’re physically cutting a hole in the surface and adding a secondary toposurface to the void. Although you can merge these surfaces back together, in some situations it can be difficult to merge cleanly.

The objective of the next procedure is to split the toposurface and create smaller toposurfaces. Follow along:

1. In the Project Browser, go back to the Site plan.

2. On the Massing & Site tab, click the Split Surface button, as shown in Figure 18.7.

FIGURE 18.7 The Split Surface button
3. Select the toposurface.
4. Zoom in on the corridor area that links the east and the west wings, as shown in Figure 18.8.

FIGURE 18.8 The split surface sketch
5. On the Draw panel, click the Start – End – Radius Arc button.
6. Sketch a perimeter similar to the one in Figure 18.8.
7. Click Finish Edit Mode. You now have a new toposurface.

Now you can manipulate this surface without influencing the main topography. This is the ideal situation for creating bumps and berms.

The objective of the next procedure is to raise this toposurface to an elevation of 4´–0˝ (1200mm). You do this by using a point and placing the datum in the middle of the berm. Follow these steps:

1. Select the newly formed toposurface, as shown in Figure 18.9.
2. Click the Edit Surface button on the Modify | Topography tab.
3. On the Tools panel, click the Place Point button.
4. On the Options bar, enter a value of 4´–0˝ (1200mm) in the Elevation field.
5. Pick four points near the center of the hill (see Figure 18.9).

FIGURE 18.9 Adding a new datum elevation
6. Click Finish Surface.

After you place the points in the model, you can still pick the points and drag them left and right, as well as up and down. Also, if you look at the site in section or elevation, you can pick the points and drag them up and down, too.
7. Go to a 3D view, and orbit around so the hill is visible.
8. If your hill isn’t brown, select the hill.
9. In the Properties dialog, in the Material field, click the […] button.
10. In the Materials dialog, select Site – Earth.
11. Click OK.
12. Deselect the topography. Your site should resemble Figure 18.10.

f1810.tif — **FIGURE 18.10** The raised area of the site

Well, I think you can see where this is going. When you work with sites, just good to have some kind of procedure. This takes us to our next perplexing situation. Suppose you want to keep the contours and the dips and hills intact, and you only want to specify a new material in a subregion of the main topography. Is this possible? Yes, it is!

Creating Subregions

The purpose of a subregion is to match two surface materials so any change in elevation or lateral movement is reflected in both regions. You need this ability for walks and most roadways. When you divide the toposurface into subregions, you give yourself the freedom to manipulate two different materials within the same datum. Another benefit of subregions is that the file size remains as if there was still one toposurface. If you were to split the surface every time you needed a path or a roadway, your file size would bloat.

The objective of the following procedure is to create a walkway path using the subregion command. Follow along:

1. Go to the Site plan.

2. Zoom in on the east entry.

3. On the Massing & Site tab, click the Subregion button, as shown in Figure 18.11.

FIGURE 18.11 The Subregion button
4. Change the view to Wireframe again, and start sketching away.
5. Draw a region similar to the one shown in Figure 18.12. (It doesn’t have to be exact.) This image shows a parking area with some pedestrian access. The inside of the parking area simply follows the building footprint.
6. In the Material row in the Properties, change the material to Site – Asphalt.
7. Change the view back to Shaded.
8. Go to a 3D view, and compare yours with Figure 18.13.

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Aug 3, 2021 | Posted by admin in Building and Construction | Comments Off