CHAPTER 20
Importing and Coordinating Revit Models

It’s amazing that we’re Up to Chapter 20 and yet I’m sure many readers are still unclear about how BIM fits in here. Yes, most of the previous chapters showed how you benefit from BIM when you change an item in one place and it changes in another, yada, yada, yada. But you were probably sold on the whole “coordinating with your consultants” thing back when you were considering purchasing Revit. Well, here we are. It’s time to tackle that mystical ideology that has put our industry in a loose headlock.

Linking a Revit structure model
Activating Copy/Monitor
Running interference detection
Importing and exporting AutoCAD

Linking a Revit Structure Model

The first section of this chapter will focus on the actual event of importing a Revit Structure model. As you start the process, you’ll see that this procedure isn’t unfamiliar if you have any CAD background whatsoever. If you don’t have a CAD background, I think you’ll find these procedures to be intuitive enough to get through importing Revit models with no experience.

As you proceed into design development, you must get your structural engineer on board. This consultant may be an external or an in-house resource. Either way, this individual will have a different model that you need to coordinate with.

This section will focus on the procedures involved with importing a Revit Structure model. We’ll also cover the concept of creating a live monitoring system with the structure as well as interference detection.

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 20 and find the file called NER-31.rvt. You’ll also need to locate the model called NER-31_STRUCTURAL.rvt. Save this file in a location where you can retrieve it.

The objective of the following procedure is to import and link a Revit Structure model. Follow along:

1. In the Project Browser, go to the Level 1 floor plan.
2. Delete every structural grid and column. (Keep the canopy framing intact. Don’t delete the beams and columns in these two areas.)

NOTE

Why are you deleting these structural members you worked so hard to add? Because the structural consultant laid out their grid based on yours. You’ll copy their grid back in and monitor any movement that may occur throughout the life of the project. As far as the columns, you’re going to use the structural engineer’s columns for your elevations, plans, and sections from this point on.
3. On the Link panel of the Insert tab, click the Link Revit button, as shown in Figure 20.1.
4. Browse to the NER-31_STRUCTURAL.rvt file, but don’t click Open just yet.
5. Select the file.

FIGURE 20.1 The Link Revit button on the Link panel of the Insert tab
6. At the bottom of the dialog, you have a choice of positioning. Select Auto – Origin To Origin, as shown in Figure 20.2.

FIGURE 20.2 Pay attention to the choices provided before you click Open.
7. Click Open. Your structural model is now linked.
8. Open the 3D view East Entry from Corridor.

You can now see the wood framing the structural engineer added to support the cantilevered slab, as shown in Figure 20.3.

Already you’re seeing the benefits of a collaborative model, and you’ve done nothing more than insert one model into another. This isn’t new technology, and you’re certainly not doing anything profound. The real benefit comes from how you can keep track of what the structural model is doing underneath your model. You can copy items from the structural model and then monitor any changes made from the linked model. This is the definition of BIM.

f2003.tif — **FIGURE 20.3** The supporting framing under the cantilevered slab at the east link

Activating Copy/Monitor

I can almost sum BIM up in one command: Copy/Monitor. I hate to break down the most import acronym in our industry since CAD into such simple terms, but building information modeling is the process of monitoring and tracking change, and that process starts right here.

The objective of the following procedure is to copy the structural grids and apply a monitoring system that will alert you when the grids have moved. Although this book will focus solely on copying and monitoring the grids, your takeaway will be the experience required to recognize the procedure and the importance of this function.

To create a copying and monitoring system, follow these steps:

1. Go to the Level 1 floor plan.

2. On the Coordinate panel of the Collaborate tab, click the Copy/Monitor button. On the fly-out, click Select Link, as shown in Figure 20.4.

FIGURE 20.4 The Copy/Monitor button on the Coordinate panel of the Collaborate tab
3. Hover your pointer over one of the grids. You see an outline of the Revit Structure model that you’ve linked in. When you see the outline, pick the grid (see Figure 20.5).

FIGURE 20.5 Selecting the link to Copy/Monitor
4. On the Copy/Monitor tab, click the Copy button, as shown in Figure 20.6.

FIGURE 20.6 Clicking the Copy button
5. On the Options bar, select the Multiple option.
6. While pressing the Ctrl key, select all the grids in the linked model.
7. When you’re finished, click Finish on the Options bar, as shown in Figure 20.7.

FIGURE 20.7 The Finish button on the Options bar
8. You may get a warning saying, “The following types already exist but are different.” Close the warning. Your grids should look like Figure 20.8.

It’s often overlooked, but you must click Finish on the Options bar, or the copying and monitoring process won’t take effect.
9. Close out of any warnings stating that new items have been renamed. This is inconsequential information.

Now that the grids are being monitored, it’s time to look at what you can copy and monitor from your consultant’s models by configuring the Copy/Monitor settings.

Adjusting the Copy/Monitor Options

By copying the grids into the architectural model, you’re proceeding with the most common, and by far the safest, function of this command. If you do choose to copy and monitor items such as foundations and columns, you can automatically replace the items being copied with an alternate component. For example, you can use Copy/Monitor on a foundation wall that is 12˝ thick but automatically replace it with a foundation wall that is 10˝ thick. Note that this example emphasizes something you would not want to do; be careful while replacing components you get from the structural model.

f2008.tif — **FIGURE 20.8** The copied grids

The objective of the next procedure is to look at the Copy/Monitor settings. Follow along:

1. On the Copy/Monitor tab, click the Options button on the Tools panel, as shown in Figure 20.9.

FIGURE 20.9 The Options button on the Tools panel of the Copy/Monitor tab
2. Notice that Revit will replace any column indiscriminately with a 24˝-square concrete column. Click into the first column category, and replace the entry with Copy Original Type (see Figure 20.10).

FIGURE 20.10 Changing to Copy Original Type
3. Change the rest of the columns to Copy Original Type, and click OK.
4. On the Copy/Monitor panel of the Copy/Monitor tab, click Finish, as shown in Figure 20.11.
5. Save the model.

f2011.tif — **FIGURE 20.11** Clicking Finish

You now have a relationship with the structural model. Next, you’ll put this relationship to the test and generate a coordination alert. I suppose you could say that the honeymoon is over!

Coordination Alert

Suddenly you’ve been thrust into a completely different way of working. You have a structural model inserted into your architectural model that will bark at you every time something changes. There’s nothing wrong with that. Sure, occasionally there will be some annoyances, but these occasional irritations are a small concession for being truly tied in with the structure.

When something changes in the structural model that is involved with an active monitor, you’ll be alerted. This alert will occur either when you open your model or when you reload the linked Revit file.

To review the coordination alert, follow this procedure:

1. Save and close your model.
2. Open the NER-31_STRUCTURAL.rvt model.
3. In the NER-31_STRUCTURAL.rvt model, open the Level 2 structural view; rename grid 2.1 to 2.2, and rotate it 5° as shown in Figure 20.12.
4. Save the model, and close it.

FIGURE 20.12 Moving grid 2.2
5. Open the architectural model. You may see the warning shown in Figure 20.13.

FIGURE 20.13 Coordination alert
6. Click OK to continue opening the model.
7. Go to Level 1.
8. Select the link (you may have to hover your mouse over one of the grids and press the Tab key).
9. On the Monitor panel of the Modify | RVT Links tab, click the Coordination Review button, as shown in Figure 20.14.

FIGURE 20.14 The Coordination Review button on the Monitor panel of the Modify | RVT Links tab
10. In the Coordination Review dialog, expand the category for the Grids (under the New/Unresolved category), as shown in Figure 20.15.
11. Expand the Grid Moved category.

TIP

The category that says Grid Moved is the actual alteration that occurred in the structural model. Finally! Somebody is telling us what they changed without fear of us getting mad at them.

FIGURE 20.15 Telling Revit to automatically move and rename the grid
12. To the right of the Grid Moved category is the Action column. Click into the cell that says Postpone, and look at the list. You’ll see four categories:
1. Reject Reject postpones the change. Each time you run a coordination review, this instance will be listed as rejected. You’ll still have a chance to modify the instance at a later date.
2. Accept Difference Accept Difference basically skips the error. You can still change it at a later date.
3. Modify Grid ‘2.1’ Modify Grid ‘2.1’ takes action. If the difference is the name (which it is in this case), Revit renames the grid. If the grid moves, Revit moves the grid for you. (Basically, any necessary modification can be made automatically right here.)
4. Postpone This will allow you to wait until later to make a decision.
13. Select Rename Element 2.1.
14. Select Modify Grid 2.1.

NOTE

You can also add a comment pertaining to the change. Typically it’s a note to yourself; but in some situations, you’ll need such a comment when you’re involved in friendly discussions about who started a chain of events.
15. Click the Create Report button at the bottom of the dialog.
16. Save the HTML file to a location where you can find it.
17. Click OK in the Coordination Review dialog. (Notice that grid A moved.)
18. Open Windows Explorer, find the HTML report, and open it. It’s an un-editable report about the coordination effort that just occurred.
19. Close the report.
20. Save the model.
21. To check whether there are any more issues, select the structural link and pick the Coordination Review button on the on the Modify | RVT Links tab as shown in Figure 20.16.

FIGURE 20.16 The Coordination Review button
22. Select the linked structural model. The report should be empty.

A coordination report is an excellent way to track changes, but you’re alerted to these changes only if you have the elements copied and monitored. How are you supposed to know if other elements are colliding with one another? This question is answered by using the Interference Detection function built into Revit.

Running Interference Detection

What came first, the chicken or the egg? That’s a tough call. Another tough call is whether the beam comes before the duct or wall. Ask a structural engineer, and they will answer that the beam does in fact come before the wall, the door, or any other architectural appointment. On the other hand, an architect will ask to move or eliminate a structural component. But the fact is, if the architect and the structural engineer are having this argument, that means they know there is an interference, and their disagreement about the chicken and the egg is actually a good thing.

You can use interference detection in Revit to keep the contractor from asking such questions. If the contractor is asking questions, then you have a problem, don’t you? It means a collision has occurred that nobody caught. Don’t worry—you can still have the chicken argument, only now it’s called litigation.

To use interference detection, you don’t have to do anything more than open a single dialog. There, you can select specific elements that you’re worried about colliding. And in true Revit form, you can create a report and even zoom in on the issue.

The objective of the following activity is to find some clashes between the architectural model and the structural model:

1. On the Coordinate panel of the Collaborate tab, click the Interference Check Run Interference Check button, as shown in Figure 20.17.

FIGURE 20.17 The Run Interference Check button on the Coordinate panel of the Collaborate tab
2. In the panel to the left of the Interference Check dialog that opens, select Current Project as the Categories From setting.
3. Select Doors and Stairs from the list, as shown in Figure 20.18.
4. In the Categories From menu to the right, select the NER-31_STRUCTURAL.rvt file.
5. Select Structural Framing and Structural Columns (see Figure 20.18).
6. Click OK.
7. The Interference Report dialog shows that you have a stair issue. Expand the first Structural Framing category, and click where it says Stairs: Stair: Corridor Entry Stairs.
8. At the bottom of the dialog, click the Show button (see Figure 20.19). You may have to go through a couple of good views to find the interference (by clicking the Show button). Get used to this.

FIGURE 20.18 Selecting the components to find in the interference report
9. You can set the visual style any way you want it, but you may have to hide some items (as I did) to see the collision.

FIGURE 20.19 The offending items are discovered!
10. Revit zooms right in on the issue. Click the Export button.
11. Save the report in the same directory as the coordination report.
12. Click Close.

That is some good stuff. Lucky for you, your consultants are all up and running on Revit. Oh, they aren’t? What kind of world are you living in?

It’s true. Your consultants won’t all be on Revit. If you’re lucky, 1 in 10 uses Revit in the capacity that they’re ready to share a model with you. This is okay—don’t panic. You’re still in a great position. You can easily import from AutoCAD (or MicroStation), and you can export your model just as easily.

Importing and Exporting CAD Formats

The first process we’ll delve into is importing an AutoCAD structural floor plan. Although you’ve imported CAD in this book numerous times, you have yet to do so in the context of a coordinated floor plan. The mindset is a little different. And why is that? Because you now care about where this AutoCAD drawing lands in relationship to your model, and you care also about maintaining that relationship.

For the CAD file used in the following procedure, go to the book’s web page at www.sybex.com/go/revit2012ner. From there, you can browse to Chapter 20 and find the file called NER-32_STRUCTURAL.dwg. Save this file in a location where you can retrieve it.

The objective of the following procedure is to import an AutoCAD 2D floor plan, and pin down its coordinates. Follow these steps:

1. Go to the Level 1 floor plan.
2. Right-click the Level 1 view in the Project Browser, and click Duplicate View Duplicate With Detailing, as shown in Figure 20.20.

FIGURE 20.20 Duplicating the view

If you have View References, Revit won’t paste them into the new view. Click Delete Element(s), and Revit will let you proceed.
3. Rename the new view Level 1 CAD Coordination.
4. Open the new view.
5. Type VG (for Visibility Graphics).
6. Click the Revit Links tab.
7. Uncheck the NER-31_STRUCTURAL.rvt model.
8. Click OK.
9. On the Link panel of the Insert tab, click the Link CAD button.
10. At the bottom of the Link CAD Formats dialog, select the Current View Only check box.
11. Set Colors to Black And White.
12. Set Layers to All.
13. Set Import Units to Auto-Detect.
14. Set Positioning to Auto – Origin To Origin (see Figure 20.21).
15. Click Open.
16. On the View Control bar, click the Wireframe button so you can see the AutoCAD structure, as shown in Figure 20.22.
17. As you can see, the underlay isn’t positioned correctly. Select the linked CAD, and unpin it.
18. Go ahead and align column lines A and 1 as shown in Figure 20.22.

f2021.eps — **FIGURE 20.21** Configuring the link

f2022.tif — **FIGURE 20.22** Unpinning and aligning the reference

The next step is to make sure the coordinates in the Revit model stay true in the DWG file. With one simple procedure, you can publish the coordinates of the Revit model to the DWG file to ensure accuracy while importing because you had to move the link. Follow along:

1. On the Project Location panel of the Manage tab, click Coordinates Publish Coordinates, as shown in Figure 20.23.

FIGURE 20.23 Publishing the coordinates
2. Select the AutoCAD link by left-clicking it in the view.
3. On the Site tab of the Location Weather And Site dialog, click the Duplicate button.
4. Call the new location Revit Position, and click OK.
5. Click Make Current.
6. Click OK.
7. Press Esc, and then select the AutoCAD link.
8. In the Properties dialog, verify that Shared Site is now Revit Position.
9. Save the Revit model.
10. After you save the Revit model, you’re prompted to save the new coordinates in the DWG file. Click the Save button, as shown in Figure 20.24.

So, that’s importing. Now, suppose you need to send your model to clients and consultants who don’t have Revit. This can be taken care of quickly and deliberately.

f2024.tif — **FIGURE 20.24** Saving the coordinates to the AutoCAD file

Exporting a Model to CAD

For some of you, this is a nice-to-know subject. But for most of you, this is a need-to-know subject. Taking the plunge into Revit may be something you’re doing alone. Even if you’re using Revit, you may still need the ability to provide CAD drawings based on your models.

This section will focus on the process of exporting your Revit model to both 2D and 3D CAD.

Exporting a 2D Model

Most of the time, your deliverable to your clients will be a 2D model. If your consultants aren’t on Revit, usually they aren’t using 3D CAD either. The 2D CAD format is the lowest common denominator. Not that a 2D model is bad—it means you need to export your model in a way that the client can pick it up and run with it.

The objective of the next procedure is to export your model to a 2D AutoCAD drawing file. Follow these steps:

1. In the Project Browser, open the Level 1 floor plan.
2. Click the Application button, and select Export CAD Formats DWG Files, as shown in Figure 20.25.
3. On the View/Sheet Set panel, select In Session View/Sheet Set from the Export drop-down list.

FIGURE 20.25 Exporting the model to CAD
4. For the Show In List option, select All Views And Sheets In The Model.
5. Scroll down to the bottom of the list, and make sure your Level 1 floor plan is selected (see Figure 20.26). You may select any others as you please.
6. Click the DWG Properties tab.
7. At the bottom, click Export Rooms And Areas As Polylines.
8. Click the Next button.
9. Browse to the directory of your choosing, and click OK.

Now that you can export to a flat 2D file, it’s time to export your model as a full 3D entity. The process is similar to exporting as 2D.

f2026.tif — **FIGURE 20.26** Choosing the items to export

Exporting the Model to 3D CAD

It’s a shame to dumb down a 3D model to flat 2D CAD. It feels as though you’re taking a step backward each time you do it. When you find yourself in a situation where your consultants are using CAD but are using 3D modeling, you can give them the gift of 3D.

The objective of the next procedure is to export a model to 3D CAD. Follow along:

1. Go to the Default 3D view.

The most important step in exporting to a 3D CAD format is to be in a 3D view.
2. Select Export CAD Formats DWG Files.
3. Set the Export option to Current View/Sheet Only.
4. Click the Next button.
5. Find a place to save the 3D model, and click OK.
6. Save the model.

As you can see, it’s not a difficult process, but it’s important to know. You’ll often find yourself exporting all your hard work and data to a lesser CAD format as you wait for the rest of the industry to catch up to you!

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20: Importing and Coordinating Revit Models

CHAPTER 20
Importing and Coordinating Revit Models

Linking a Revit Structure Model