Export CAD Formats lets you export a view or sheet of the model into a 2D or 3D CAD format. The following CAD file formats can be exported directly from Revit: .dwg, .dxf, .dgn, and .sat.

The DWFx format allows you to share your project documents with others who do not own or know how to use Revit but need to examine or review your design. DWF files are a way to share rich geometry and metadata while maintaining ownership of the intellectual property in your files. The exported DWF files are small, which makes them easy to email, something you cannot do with a large Revit file.

You can export to DWF any view/sheet in Revit, regardless of whether the containing information is 3D or orthogonal 2D views. To export your active view, simply open the Application Menu and choose Export → DWF. The DWF Export Settings dialog box (Figure 7.1) will open and let you choose which views/sheets to export. The default is your current view. After selecting what you wish to export, give your file a unique name and save it. The recipient of the DWF file can then open it with Autodesk® Design Review, free to download from www.autodesk.com, to see the result and make any further comments and markups as you review the files.

You can also publish the exported DWF files directly from Revit to Autodesk® Buzzsaw®, a free, integrated, all-digital way to view, print, mark up, and compare versions of drawings, maps, and models—an on-demand collaborative project management solution for organization of construction-related documents. To access that option, go to the Application menu and select Publish → DWF to Buzzsaw.

Figure 7.1. DWF Export Settings dialog box

Sharing a rich 3D BIM model with other professionals can prove to be problematic because of its complexity and size. Depending on the professionals you need to share BIM geometry and information with, they usually need just a subset of the rich information contained in the BIM model but have little flexibility to control this on their end.

To accommodate this, Revit 2010 has introduced a new smart way of sharing a BIM model made by architects using Revit with civil engineers using AutoCAD Civil 3D software: the BIM model is shared in a way that's simplified and relevant to civil engineers.

With the help of this new functionality, you can export the following types of information relevant to the civil engineers who work on developing the site around your project and need a certain set of information about your building as a context for their work:

The Export Building Site functionality can be found in the Application menu, under the Export Building Site option. To make a meaningful export to a building site, you will need to make some preparations in your model. At a minimum you will need to have at least one gross area defined—the one that represents the building footprint. If you initiated the export to the building site without having defined a gross area, you will be prompted to do so. You should export as little data as possible and choose what will be most meaningful for the civil engineers. For example, there will be many doors in your project, so you will need to assign to the doors a Type property that defines whether they are exterior or interior and then filter out (turn off by type) the interior doors so that you export only the exterior doors to your civil engineers. The rest of the exported information, such as the finished floor height, roof slope and area, and property line information will be reported directly from the parameters of your building elements.

Once you select Export to Building Site, the Building Site Export Settings dialog box opens and informs you about your current export settings (Figure 7.2).

Figure 7.2. Building Site Export Settings dialog box

The exported file formats are new to the industry and announce new ways in smart interoperability with applications such as AutoCAD Civil 3D:

It's possible to export any of the views within Revit to an image file. You can also create walkthrough animations and animated solar studies in Revit and save them as .avi files.

Exporting Images

To export a Revit view to an image file, open the desired view, and from the Application menu choose Export → Images and Animations → Image.

In the Export Image dialog box (Figure 7.3), many of the options are similar to the other export and printing functions. Export Range, for example, gives you the option to export either the current view or a series of views, similar to the Print dialog box.

Figure 7.3. Export Image dialog box

The Name field allows you to browse to a path in any of your folder directories to place the image. By default, the image name is the same as the view name. Similar to the options available when printing, you can choose to exclude elements such as crop boundaries, scope boxes, and work planes. This will give you nice results without having to worry about turning categories on and off every time you want to print or export an image.

Revit can export any view or sheet in several image file formats: .bmp, .tif, .tga, .png, or .jpg.

CREATING A BROWSABLE WEBSITE FROM THE REVIT MODEL

When more than one view is selected for export to image, pick Selected Views/Sheets under Export Range, and an option becomes active in the Output section of the Export Image dialog box that lets you create a browsable website with a linked HTML page for each view, as shown in Figure 7.4.

Revit exports every view as an image and links to them with an HTML file, all packaged neatly into a folder. This allows you (or someone else) to scroll through the project views quickly and easily.

Figure 7.4. Browsable website page

Note

This technique is practical when you create PowerPoint slides for a project presentation and need all views exported in image formats.

IMAGE SIZE

This section in the Export Image dialog box allows you to set the size of the exported image. You can either fit it to specific pixel dimensions or zoom the image to a proportion of its actual size. Keep in mind that this is a proportion of the view size, not the model. So, if your view dimensions are 10" × 10" (25 × 25 cm), and you're zooming to 50 percent, your exported image will be at 72 pixels per inch (ppi) and 5" × 5" (10 × 10 cm), not at 1:2 scale.

FORMAT

This section in the Export Image dialog box allows you to choose your export file type from the list shown earlier in Figure 7.3. It also gives you the option to raise the pixels per inch (ppi) exported from 72 ppi to a higher density. The more ppi, the longer the export time will be, and the larger the final image file. As a general rule of thumb, use 72 ppi for images that will be viewed only on a monitor or screen. Use 150 ppi for images that will be sent to a laser printer and 300 ppi for any image printed by an offset press or when there's a need for high-resolution imagery. Figure 7.5 shows an example of an exported image.

Figure 7.5. Exported image

To export a walkthrough, from the Application menu choose Export → Images and Animations → Walkthrough. You'll find the Walkthrough tool on the View tab, in the Create panel under 3D View.

Revit lets you make animated solar studies, and those can also be exported as .avi files. To export an animated solar study, use the same location: from the Application menu choose Export → Images and Animations → Solar Study. Creation of solar studies is covered in Chapter 8.

You can export almost all the information embedded in your Revit model to an ODBC table. Doing so creates a link between your Revit file and another external database such as Excel, Access, FileMaker Pro, or SQL Server. ODBC gives you the opportunity to download data from any of the tables in Revit directly to a database using the Microsoft ODBC connector. An example of this functionality is a cost-estimating software add-on package that gets material quantity take-offs directly from the model.

ODBC is an advanced topic that we won't cover in depth in this book. However, if you do need to export to a database, here's how to use the Microsoft ODBC connector:

Next, create the database file:

You just created a database output out of your Revit model. If you chose Microsoft Access as a driver, you can open the .mdb file you created in Microsoft Access and view the database of all Revit elements in the project.

The FBX is a widely used and supported platform-independent 3D data exchange platforms. It enables export of a 3D model and all the material definitions, so you can open the file in 3ds Max or other modeling/rendering applications and do more advanced renderings and animations. All the materials assigned in the Revit model will translate 100 percent into 3ds Max.

Green Building XML (gbXML) is an XML data type that was created to support the growing trend of sustainability and green building design. As a data type specific to the building industry, gbXML is an export function within Revit and other BIM applications that allows you to export specific data about a model for the purpose of performing energy analysis and evaluating building performance. A number of different applications are available that can read gbXML-formatted files. These applications are primarily designed around performing energy analysis using the Revit model as a basis. This saves a tremendous amount of time, allowing you to reuse your model geometry instead of re-creating it in another analysis application. Some of these energy analysis applications are Autodesk Green Building Studio (www.greenbuildingstudio.com), Autodesk Ecotect (http.//ecotect.com), and IES <VE> (www.iesve.com). You can find more information on them at www.gbxml.org. (At the time of publication, these URLs are still correct, even though Autodesk bought the products.)

Improvements to the gbXML import in this release of Revit Architecture 2010 are as follows:

To export to gbXML, go to the Application menu, choose Export, and select gbXML. The Export gbXML dialog box (Figure 7.7) will open, showing the analytical preview of your model and displaying all settings that are relevant to this export.

Figure 7.7. The Export gbXML dialog box

Industry foundation classes (IFCs) allow for exchange of intelligent data between architectural and downstream applications, based on the STEP application protocol. IFC is a nonproprietary file format that has been recently resurrected as a possible BIM interoperability standard. The goal is to allow the transfer of information between models that have been created using different BIM authoring packages. More information on IFCs and their current and future uses can be found at www.iai-international.org.

Revit Architecture 2010 supports first-stage IFC 2x-3 certification import and export. Revit also has full (second-stage) IFC Singapore Code Checking (BCA) certification, which is export only. IFC can be imported into any other BIM or CAD application that accepts IFC class files.

In the View/Sheet Set tab you can manage the sheet sets (add, remove, rename, and so on) or define what exactly will you be exporting. The latter is done in the Export drop-down list (up to this release this functionality was described as Range).

With this box checked, Revit exports each view on a sheet into a separate file and creates a cross-reference (XREF) to the files. If you're exporting a single view, using this feature won't make much difference, but if you're exporting a series of sheets with a number of views on each sheet, this feature will have a very different effect. In this case, with the box checked Revit exports each sheet as a separate file as 2D vector-type views, and then those separate files are combined via XREF within a parent file. For example, if you start with a sheet with four views on it, five DWGs will be exported. With this option unchecked, the views and parent sheet will be a single file with all of the views in the drawing as blocks. In other words, the XREFs will be "bound" on the sheet.

The second tab in the Export CAD Formats dialog box is the DWG Properties tab.

The DWG Properties tab of the Export CAD Formats dialog box, shown in Figure 7.10, gives you some advanced options for exporting to CAD formats:

In previous releases of Revit, there were some additional options and advanced settings in this dialog box that now have been moved and are accessible from the Application menu under Export, at the very bottom of the list (Options). There you will find the following settings:

Linking creates a live connection to another file stored somewhere else. This allows you to work on the linked file separately and then have the Revit model update to reflect the changes in the link. This behavior is similar to an XREF in AutoCAD.

Linking CAD Formats

The ability to link one file into another can be helpful in a collaborative environment. Perhaps someone on your team—a person working on details within your office or an external consultant—is working in an AutoCAD environment while you build up the project in Revit. Linking lets you have her latest work updated in your Revit model. If you import without linking, you get a static file that will not update. When you link, it's possible to always get the latest state of the DWG by updating the link within Revit.

Switch to the Manage tab and, in the Manage Project panel, select Manage Links. Here you can reload, unload, import, or remove a CAD link or see what is already loaded (Figure 7.14).

Figure 7.14. Managing links

To link an RVT file, go to the Insert tab and under the Link panel, choose Link Revit. The resulting dialog box looks like Figure 7.15. This dialog is a standard file-open format, with a few options specific to Revit: Open Worksets and Positioning. We'll look at each option and explain what it means.

Figure 7.15. Import/Link RVT dialog box

Positioning

The Positioning drop-down list provides options for linking the model. You can choose Auto or Manual placement methods, as shown in Figure 7.16.

Figure 7.16. Positioning options

The Auto placement options will do the following:

Center to Center

Aligns the 3D center points of both models.

Origin to Origin

Places the world origin of the linked file at the model's origin point. If the linked model was created far from the origin point, linking with this option may put the linked file far away from the main model.

By Shared Coordinates

Places the linked file geometry according to the shared coordinate system created between the two files. If no shared coordinate file has been created, Revit will alert you.

What Are Shared Coordinates?

Every Revit project has an internal origin that can be related to other projects. When a project location is moved or rotated, this information is used to create relative positioning between files. Basically, a shared parameter is a user-defined origin.

Acquire Coordinates

Allows you to take the coordinates of the linked file into the host model. There is no change to the host model's internal coordinates; however, the host model acquires the true north of the linked model and its origin point.

Publish Coordinates

Allows you to publish the origin and true north settings to your linked model. Revit understands that there may be other things in your linked file and you may not want this to be a global change to the linked file. An additional dialog box appears that gives you the option to name separate locations for each set of coordinates.

Specify Coordinates at a Point

Allows you to manually key in X, Y, and Z coordinates relative to the origin point or define where you want your 0,0,0 point to be.

Figure 7.17. Reported coordinates

Report Shared Coordinates

Shows the E/W (east–west, or X), N/S (north–south, or Y), and Elevation (Z) coordinates of any point in the model (see Figure 7.17).

The Manual placement options for links do the following:

Cursor at Origin

Puts the origin point of the linked model at your cursor location.

Cursor at Base Point

Puts the base point of the document at your cursor location. This is primarily used for files that have a base point, such as CAD files.

Cursor at Center

Puts the 3D center of the building at your cursor location.

Site plans, consultant files, and details or drawings done with CAD technologies on prior projects all are examples of information you may want to link or import into Revit from a CAD format. This isn't limited to 2D data; you can link 3D files and data as well.

The data you import or link into your model can be view specific (imported and visible in one view only, as opposed to all views), so start by opening the view into which you want to bring data. In this release of Revit, the import and link of CAD formats is separated into two commands located in the Insert tab: the Link CAD command is located under the Link panel, and the Import CAD command is located under the Import panel.

As discussed previously in this chapter, you can link or import five types of CAD files in 2D or 3D in Revit:

In every project, you'll need to import an image—be it a photograph of the site and its surroundings; background information, such as scanned hand drawings of a historic building; or images that can represent advertising or marketing material (see Figure 7.19).

Figure 7.19. Inserted image

To import an image into Revit, switch to the Insert tab and, from the Import panel, select Image. Navigate to the appropriate folder, and choose your image file. You can also drag and drop an image file directly from Windows Explorer into a Revit view. Imported images are specific to the particular view you've imported them into.

Once you've inserted the image, you have a few options to edit its size and proportion. Selecting the image highlights the corner grips and lets you resize the image dynamically. Doing so also highlights the Options bar. The Options bar allows you to push the image forward or backward or bring it all the way to the front or back. The Background/Foreground selection tells the image that you want it above or below the model geometry. You can also change the shape of the image by deselecting the Lock Proportions check box.

Once you select an imported image, you can enable the Type Selector by clicking the Change Element Type button. The Type Selector will let you toggle between different imported images just as you would for any component family.

The Instance Properties dialog box shown in Figure 7.20 controls the same element parameters that appear in the Options bar when an image is selected but provides a bit more precision. From here you can set the exact size of the image in project units. Figure 7.20 shows how the image looks when the Draw Order property is set to Background.

Figure 7.20. Image properties and an image placed in the background of the model

Once your CAD file is imported into Revit, either as a link or as an import, you can begin to manage the layers and colors of the CAD objects as they appear in Revit. To do this, use the Visibility/Graphic Overrides dialog box. You can access this dialog box in three ways:

If you import a CAD file into your view, Revit adds an Imported Categories tab to this dialog box. Selecting that tab, shown in Figure 7.21, gives you a list of all the CAD files imported into this particular view. Remember that this list is view specific; Revit changes the list as you add or remove CAD files from the model and from this view.

Selecting the check box next to the name of your CAD file displays a list of every layer present in the file. Use the check box in front of the layer name to control its visibility. Here you can also override the line color and pattern of the layer or turn it to halftone.

Figure 7.21. Visibility/Graphic Overrides dialog box

Often, you'll need to modify or delete some of the geometry in a CAD file that has been imported into Revit in order to simplify it and prepare it for use in your project. Let's review how this works and all the options available. To start, open the view your DWG is imported into, and click the DWG to select it. Let's take a look at the opened Modify demo and the Import Instance panel (shown in Figure 7.22).

Figure 7.22. DWG Import Instance panel

Delete Layers

This tool lets you delete an entire layer from the imported file. With the DWG selected, click Delete Layer, and select from the list of displayed layers those you wish to delete. A sample dialog box with its associated layers is shown in Figure 7.23. As with most Revit dialog box lists, you have the option to select all or to select none as well as to invert the order of choices.

Figure 7.23. Select Layers/Levels to Delete dialog box

Explode

PARTIAL EXPLODE

The Partial Explode option disassembles the imported file into the first and highest level of entities: blocks, attributes, unassociated lines, arcs, and circles. Blocks remain as blocks and aren't converted to individual lines. In cases where you have blocks within blocks in your inserted CAD file, a first partial explode explodes the drawing, leaving the nested blocks combined. A second partial explode explodes the nested block, leaving the block within that block intact. A third partial explode turns everything into lines.

FULL EXPLODE

The Full Explode option disassembles the entity as well as any blocks or attributes and simplifies it to the lowest level of lines, arcs, texts, and hatches (filled regions). Note that Revit doesn't allow linework or other elements smaller than 1/32" in length (0.8 mm). If you explode a CAD file with line elements shorter than these lengths, they will be deleted.

Note

Given the fact that exploding DWGs can produce a multitude of elements that pollute the database and may affect the performance of the overall application, it's strongly recommended that you consider exploding only when you need to modify the imported DWG. As an alternative, consider using Partial Explode, which may be sufficient to achieve the desired modifications.

Query

The purpose of the Query tool is to find the attributes of individual blocks and layers without having to explode the DWG. After you import a drawing into a project, you can query the inserted object for information about entities contained in the drawing. After you click Query and click an entity, Revit first highlights the lowest-level entities. To select a block within the CAD file, use the Tab key to cycle through your selection options (see Figure 7.24).

Figure 7.24. Query selection

Selecting an entity causes the following information about that block or line to be displayed:

Type

Information about the type of the entity selected (line, text)

Block Name

The name of the block that contains the entity, if applicable (N/A means "isn't available"; the entity doesn't belong to any block)

Layer

The name of the layer containing the entity

Style By

Indicates whether the entity style comes from the layer or is defined by color

These results are reflected in an Import Instance Query dialog box (Figure 7.25).

Figure 7.25. Import Instance Query dialog box

To find out the property information of the layer or instance, select the DWG, click the Query tool located on the Import Instance panel, and click the object or geometry that you want additional information about.

Once you have this information, you can do two things:

• Delete the layer on which that instance belongs

  Note

  Once you delete a layer, you can't recover it from anywhere unless you use the Undo function or re-import the DWG.

• Hide the layer in that particular view

  Note

  To turn the visibility of a layer back on after using the Hide in View command, choose Visibility/Graphics → DWG/DXF/DGN Categories.

In this exercise, you'll transfer an imported DWG data into Revit and make it into a Revit toposurface:

Now, this might be very confusing, as Figure 7.30 doesn't look much different from the DWG you started with. Switch to a 3D view, and activate the shaded view. Now you can see the topography you've created (see Figure 7.31).

The default material for the topography is Site – Earth, as defined in the Object Styles dialog box shown in Figure 7.32.

Figure 7.30. Finished toposurface in site and 3D view

Figure 7.31. Shaded toposurface

Figure 7.32. Object styles for topography

If you want to change the material of the topography, select the topography and click the Elements Properties button. In the Instance Properties dialog box, under Material, choose another material (try Site – Grass). The topography will turn green.

If you want to change the default material of the topography, switch to the Manage tab, and under Settings select Object Styles. In the Object Styles dialog box, change the default material for the Site category.

You'll notice that there are many 2D lines on your toposurface that you don't need. Those come either from the contour lines from the imported DWG or from the Revit toposurface primary and secondary contours. Revit allows you to control the visibility of those separately using the Visibility/Graphic Overrides dialog box.

Open the Visibility/Graphic Overrides dialog box, scroll to the Topography Model Category node, as shown in Figure 7.33, and uncheck all subcategories of Topography. You have thus made the primary and secondary contours of the topography invisible in this view.

Now, switch to the Imported Categories tab, and uncheck the entire imported site. To uncheck all the subcategories at once, you can deselect the parent heading, as shown in Figure 7.34. Click OK. Doing this should remove the now-unnecessary DWG line work of the site so it looks much better: You now should see a nice, smooth topography covered with grass.

Figure 7.33. Visibility/Graphic Overrides for topography

Figure 7.34. Visibility/Graphic Overrides for imported files

There are two other ways to create topography in Revit besides using an imported DWG:

Importing a Points File

You can automatically generate a toposurface based on a points file. A points file is a list of points described with their X, Y, and Z coordinates. It must contain X, Y, and Z coordinate numbers and be in a comma-delimited file format (.csv or .txt). If you receive a points file from a civil engineer, you can view it in Notepad or Microsoft Excel. Here is an example of creating a toposurface from a points file:

• To create a toposurface from a points file, follow these steps:

  1. Switch to the Massing & Site tab.

  2. From the Modeling Site panel, select the Toposurface tool.

  3. From the Tools panel, expand the Create from Import button and select Specify Points File.

  4. In the Open dialog box, select the Points.csv file from the book's companion web page under Chapter 7. (Note that only .csv and .txt file formats are recognized.)

  5. On the Format tab, set the units in which the points file needs to be imported (see Figure 7.35).

     

     Figure 7.35. Setting the unit format

  6. Click the Finish Toposurface button. Figure 7.36 represents an editable toposurface in Revit and the completed toposurface.

Note

Depending on the file you import, after the import you may not see anything on the screen. This means your site is outside of the crop region predefined for the site. To find your site, deactivate the crop region and choose Zoom to Fit All to find the site.

Figure 7.36. Left, an editable toposurface; right, the finished toposurface

Creating Topography from Scratch: Drawing Points

When you don't have any civil engineering data to import and convert to topography but you do have a paper drawing with points information, you can create your toposurface by drawing points and defining their heights. Revit will create a smooth toposurface out of them.

1. Create a new project and switch to a site view.

2. Switch to the Massing & Site tab, and from the Create Site panel, click the Toposurface button.

3. From the Tools panel, select Place Point.

4. Start drawing points that define your site contour. (Try it with four points to start with, as shown in Figure 7.37.)

5. Revit closes the points into a loop.

   If you don't change anything and just draw four points, all points have the same elevation of zero (Z coordinate = 0). You can give them a height coordinate during the drawing by typing their elevations in the Options bar (

   

   Alternatively, after you've defined the shape in plan view, you can start reselecting and defining elevation coordinates. For the moment, leave the four initial points at 0.

6. Without finishing the toposurface, draw an additional four points, select them all, and change their elevation to 20" in the Options bar (see Figure 7.38).

7. In the Surface panel, select Finish Surface. Revit will grade the distance between the elevations with contour lines, as shown in Figure 7.39. If you zoom in, you'll notice that some lines are stronger and some are lighter. Those that appear stronger are the primary contours. The lighter ones are the secondary contours.

   

   Figure 7.37. Creating your own toposurface from points

   

   Figure 7.38. Adding contours to a toposurface

8. From the Quick Access toolbar select the 3D icon to switch to 3D view, and from the View toolbar activate the shaded view or click the shortcut SD (Figure 7.40).

   

   Figure 7.39. The graded toposurface

   

   Figure 7.40. Completed toposurface

As with any other preset, you define the distance at which the secondary contours are placed: switch to the Massing & Site tab and expand the Modeling Site panel (click the little arrow on the right of the panel). You will get the Site Settings dialog box shown in Figure 7.41.

In this dialog box, you can also define or change the material that appears in section when the toposurface is cut. It's also where you can control the height in elevation where the base of the toposurface begins to show in section view—if you make a section through the site, you should see what's shown in Figure 7.42.

Figure 7.41. Site Settings

Figure 7.42. A toposurface in section

The default settings place the primary contour lines at 10' (3 m) intervals. If you change that to 5′ (1.5 m), you'll see a site similar to that shown in Figure 7.43.

Notice the placement of the secondary contour lines. Revit's default settings place them at 1′ intervals. Change that to 2′ and note the differences in the contours displayed in the model (Figure 7.44).

Figure 7.43. Toposurface with 10' primary contours

Figure 7.44. Toposurface with 2' secondary contours

Figure 7.45. Toposurface with contour labels

The contours can also be labeled to indicate their elevation. To label the contour elevations, switch back to site view, select the site and from the Massing & Site tab, under the Modify Site panel select Label Contours (

As with everything in Revit, you can edit the topography at any point later in the process. To do so, select the topography so that it becomes red, click the Edit Surface button on the Surface panel, and modify the site as needed.

All three of the methods described show you how to create a toposurface in Revit. Of course, creating the toposurface is only the beginning. You still have to position your building at the correct location and elevation, create a pad for the building to sit on, and position the parking lot, the walkways, and other contextual features (Figure 7.46). Dealing with site tools, however, is a more advanced topic that won't be covered further in this book.

Figure 7.46. There's a long way to go from toposurface creation to finished site

Most of the floor plans that you have imported as reference drawings will have gridlines. Generating Revit gridlines from imported lines is simple: in the Home tab, from the Datum panel, select the Grid tool and set the creation method to Pick Lines in the Draw panel. Next, pick any gridline from the imported DWG. Revit will create a gridline on top of the DWG gridline and number it. Revit usually starts with the number 1, but if the DWG grid uses lettered coordinates, you can change the Revit gridline on the first one you create. The remainder will number (or letter) in incremental sequence, so they should append correctly. Otherwise, you can renumber them later.

Figure 7.50 shows an imported DWG image. In the second image, the gridlines have been converted to Revit grids using the pick method. Note that the grid bubbles in Revit change dynamically with the view scale. If the bubble sizes don't match, don't panic—just check your scale factor.

Figure 7.50. The image on the top shows the view with DWG import; the bottom image shows Revit gridlines created using the import lines

If you have multiple floor plans where the gridlines aren't the same for all levels, you need to use the Scope Box tool. This tool limits the range in which datums (grids, levels, and reference lines) appear, which by default is across the entire project and throughout all levels. Imagine that you have a building with a shopping center on the first three floors and a hotel tower above. The grid systems for the lower and upper parts of the building will be different, and you do not wish to see the grid system of the lower building in the floor plans of the upper building and vice versa. You need to create two scope boxes, assign the grids from the first three levels to one scope box and the rest to the other, and control the area covered by each scope box so they show up correctly. Figure 7.51 shows how scope boxes work in a 3D view.

Scope boxes are also visible in 3D views (although not in perspective views), and you can easily manipulate their extent directly using the grips. Assigning grids or other datums to a scope box is easy: select the grids, choose Element Properties, and in the Instance Properties dialog box under Scope Box select the scope box where the datums should belong. Figure 7.52 shows the Instance Properties dialog box for the grids and the associated scope box.

Figure 7.51. Scope boxes can be seen in 3D

Figure 7.52. A scope box can be assigned to grids using the Instance Properties dialog box

Using DWG Lines as a Reference to Create Revit Floors

After you create the walls, the next step is to create floors. To create floors, select Floor from the Build panel of the Home tab and select the Pick Lines from the Draw panel. Hover your cursor over the outer edge of the floor or walls and press the Tab key until the DWG floor lines are highlighted. Click to generate sketch lines. If the shape of the floor isn't the shape you want, make corrections using the Edit tools. Remember, a sketch is a line drawing that has to form a closed loop so Revit can create an object out of it.

Figure 7.53. Beginning the conversion process – DWG linework is used as reference to create Walls

In Figure 7.54, the lines in the DWG that represent the outer wall faces have been selected, the magenta lines have been adjusted to a rectangular shape (using trim lines), and the floor has been created.

Note

If your workflow permits, draw interior walls before you create the floors so that when you create a floor, it will be attached to the walls and have a relationship with them.

Once you have your wall and floor structure, it's easy to start adding windows, doors, and other elements.

Figure 7.54. Creating floors from DWG linework

Autodesk's i-drop technology allows you to drag and drop content (drawings) from the Web directly into a Revit drawing. This corresponds to the DWG import process and utilizes Revit's default import settings. From a workflow perspective, it's practical. As you work on your project, you can quickly go to the Web and search for a detail or piece of content in DWG format. Once you find what you need, you can drag and drop it into your Revit file.

Many manufacturers now have their content in i-droppable 2D or 3D DWG format. Figure 7.55 shows some sample i-drop content.

Figure 7.55. i-drop examples

Another source of downloadable library components that can be useful in Revit is Google's 3D Warehouse, which offers files in SketchUp (.skp) format. Revit can read SKP files, and you can import SKP files into an RFA (Revit family file) to create content. These families aren't always parametric—many families don't need to be parametric—because certain manufacturer content exists only in single dimensions and shapes. Figure 7.56 shows some samples of SketchUp content.

The best way to utilize this 3D content is to create a new family (from the Application Menu, choose New → Family) and select a family type, such as furniture or plumbing fixtures. You then can import a 3D SketchUp model into this family. If needed, you can quickly create simplified orthographic projections using the Linework tool instead of using a 3D object to generate those projections. This is useful if you need to show simplified versions of the 3D object in plan, elevation, or another orthogonal view. More details about family generation are covered later in this book.

You can learn more about 3D Warehouse at http.//sketchup.google.com/3dwarehouse.

Figure 7.56. Sample SketchUp content