Whether you work on large or small projects—residential, commercial, or industrial building types—collaboration is an almost certain aspect of the workflow you will encounter when implementing BIM. This chapter discusses important considerations for interdisciplinary coordination as well as the tools within Autodesk® Revit® software to help you manage the process. This chapter covers aspects of collaboration solely utilizing the Revit platform, and Chapter 7, “Interoperability: Working Multiplatform,” focuses on collaborating with other software programs.
In this chapter, you’ll learn to:
Working alone in the Revit environment will deliver measurable increases in productivity, quality, and consistency; however, the true benefit of building information modeling (BIM) is the ability to effectively collaborate between design disciplines, share model data with contractors, and deliver useful information to facility operators.
The difference between these working paradigms has been described as lonely BIM versus social BIM. Lonely BIM can be thought of as the use of isolated BIM techniques for targeted tasks such as architectural design or structural analysis. Social BIM is the act of sharing model data between project stakeholders in order to enhance collaboration while developing a building design. The importance of increased efficiency in collaboration is the underpinning for the goals set forth by organizations such as buildingSMART International (www.buildingsmart.org) or the UK’s BIM Task Group (www.bimtaskgroup.org).
The ability to support high-quality information exchanges necessitates the proper use of 3D models and nongraphic data in a highly collaborative environment. Although we will be discussing collaboration solely within the Revit platform in this chapter, the buildingSMART Alliance and the National BIM Standard (NBIMS-US) stress the need for open interoperability between BIM applications.
Once a project team decides to participate in social BIM—either through desire or the requirements of a client—they must decide how to collaborate with BIM in a manner that is useful to all constituents throughout the project life cycle. Whether or not your client requires it, you should develop a BIM execution plan in order to set clear expectations related to the use of BIM.
The buildingSMART Alliance (www.buildingsmartalliance.org), in an effort sponsored by the Charles Pankow Foundation, the Construction Industry Institute, the Penn State Office of Physical Plant, and the Partnership for Achieving Construction Excellence (PACE), has created a “BIM Project Execution Planning Guide” and template for a BIM execution plan. You can find this information at the Penn State Computer Integrated Construction (CIC) website: http://bim.psu.edu.
One of the most critical parts of a BIM execution plan is the definition of the project goals and uses of BIM to achieve the stated goals. If you are just beginning your implementation of Revit software, you may be using it to create 3D visualizations, or perhaps you are attempting to increase your drafting productivity. Defining clear and concise reasons for implementing BIM on each project will help you define where to concentrate your modeling efforts. According to the buildingSMART Alliance, “[A] current challenge and opportunity faced by the early project planning team is to identify the most appropriate uses for Building Information Modeling on a project given the project characteristics, participants’ goals and capabilities, and the desired risk allocations.” A listing of the common uses of BIM along with potential value opportunities and required resources is also available on the Penn State CIC website. For our European counterparts, you can find another list here: aecuk.wordpress.com/documents.
According to the American Institute of Architects’ “Integrated Project Delivery: A Guide,” a BIM execution plan “should define the scope of BIM implementation on the project, identify the process flow for BIM tasks, define the information exchanges between parties, and describe the required project and company infrastructure needed to support the implementation.” To be clear, the development of such a plan does not imply the application of integrated project delivery (IPD). IPD is “a project delivery approach that integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to optimize project results, increase value to the owner, reduce waste, and maximize efficiency through all phases of design, fabrication, and construction.” For the purposes of this chapter, we will consider only the collaboration and coordination between members of a project design team, not the interactions with a client or contractor.
For additional reading on IPD, refer to these sources:
The coordination process in a Revit environment begins with linking multiple files together to form a composite view of your building project. Even though smaller projects might be coordinated within a single Revit project file, most moderate to large projects will be designed by multiple disciplines or trades working in different offices. A project can be divided in many different ways to meet a variety of workflow requirements. Most often, each discipline will develop at least one separate Revit project file, and many of these project files will be linked into each other for reference. Because there are several workflow possibilities, this chapter will focus on the coordination among a traditional design team consisting of the following:
The workflow within a traditional design team is more complex than you might assume. If you were to graph the dependencies and coordination between these parties (Figure 6.1), you would see a web of primary relationships (architect to/from structure, architect to MEP) and secondary relationships (structure to/from mechanical and piping).
These relationships can be further parsed into physical and logical relationships. If we use mechanical and electrical as an example, you can see that a physical relationship means making sure a light fixture is not hitting the bottom of a duct, whereas a logical relationship means making sure the electrical design properly accounts for the load of the heating coil in a variable air volume (VAV) box (being designed by the mechanical engineer).
It is the complexity of these possible workflow scenarios that makes this process prone to errors and illustrates the importance of proper coordination between the different disciplines of a design team. So, what are the tools that can be used for collaboration between Revit products? Three distinct tools are typically used in a collaboration scenario:
Linked Models Linking models together using the Link Revit tool provides full visual fidelity of the referenced content, showing the complete context of the other disciplines’ data, fostering a complete understanding of their geometry. The data can also be controlled and shown in any manner appropriate to the use. You can turn it on or off, half-tone the data, or enhance it with color or line pattern overrides. Linking also provides support for the Interference Check, Copy/Monitor, and Coordination Review tools.
Copy/Monitor Copy/Monitor is a powerful tool available in all products built on the Revit platform and is considered the most intelligent of the coordination tools. It offers several benefits. It lets you link Revit files from other team members (structural engineers or MEP engineers) and copy key elements from their model into yours. Once that link is created, you can monitor that relationship and know if the element has moved or changed when you receive updated models from your team members. A basic example of using this tool would be copying the structural grid into your architectural file. If the grid moves or changes with subsequent updated models, you will be instantly alerted to the change.
Interference Check In many cases, the only workflow requirement is to verify that items from another discipline are not interfering with your items. The Interference Check tool can be used to check between categories within a single model or between linked models.
Given the range of available Revit tools for collaboration, they are not necessarily applicable to all interdisciplinary relationships. As shown in Figure 6.2, only the most appropriate tools should be applied to each collaborative situation. These situations are merely suggestions based on the experience of the authors. The needs for your collaborative workflows may vary.
Architect to Structural Engineer The relationship between the architect and the structural engineer is becoming closer as we strive for lighter structures and more innovative design. In many respects, structural engineers may be affecting the building aesthetic as much as the architects. Thus, this workflow may be considered the most crucial and should be bidirectional.
Architect to Structural Engineer: Copy/Monitor and Coordination Review By using Copy/Monitor, structural engineers are able to create a strong, intelligent link between the structural and architectural models. In doing so, they can easily track the changes in the architect’s model that will affect the structural design. They are also able to create geometry in their model using these tools, which can be directly or indirectly related to architectural elements such as walls and floors.
Remember that coordination of relationships for datum (grids and/or levels) should be established at the beginning of a project. For example, does the architect “own” the levels and the grids—or will the structural engineer? Conflicts due to a lack of proper planning will negatively impact the effective use of the Copy/Monitor tools on your projects.
Structural Engineer to Architect: Interference Check The architect’s primary requirement for the structural model is to include the structure in context and to know if the structure is interfering with any architectural elements. For this workflow, it is recommended that the architect link in the structural model and use interference checking. The rules governing what clashes are considered critical may be established by a client’s BIM standards and protocols.
Architect to MEP Engineer The relationship between architecture and MEP is not quite as dynamic as that between architecture and structure but represents specific opportunities to benefit from collaboration.
Architect to MEP Engineer: Copy/Monitor and Coordination Review The MEP engineer needs to link in the architect’s model to have the architectural model for context and positional relationships for ceiling-based items and the avoidance of clashes. Copy/Monitor is used to copy and monitor the architect’s levels and rooms. These room objects take on the additional properties, such as light levels and airflow. Levels are required to copy or monitor the rooms.
MEP Engineer to Architect: Linked Models The architect’s primary benefit from linking in the MEP model(s) is the ability to reference this geometry within the context of the architectural model and drawings. There is usually no compelling reason to use the Copy/Monitor and Coordination Review tools from the MEP on the architectural project, although interference checking may be required under certain circumstances.
Structural Engineer to MEP Engineer This relationship is almost always best served by cross-linked models using interference checking. The most important aspect of collaboration between these disciplines is the early detection and correction of clashes.
The first rule governing all Revit-to-Revit coordination situations is that all linked project files must be generated with the same Revit platform version, such as Autodesk Revit 2017. In a worksharing environment with other disciplines, it is important to ensure that the computers of all team members working on a project have the same Revit build installed. As discussed previously in this chapter, a BIM execution plan should include an agreement on all modeling and coordination software to be used on a project, including the version of each listed program.
You can find the build information for your Revit product by clicking the Help drop-down button in the InfoCenter and selecting About Autodesk Revit 2017 (Figure 6.3). The build appears at the upper right of the About Autodesk Revit 2017 dialog box.
In the collaborative process of sharing information via linked models, the coordinated positioning of each model is of paramount importance. To ensure accuracy, every project’s BIM execution plan must include agreement on a common coordinate system and origin. This section will help you develop a fundamental understanding of the coordinate systems within Revit so you can configure and manage them in your projects.
We will begin our description with a simple statement: There are two coordinate systems in a Revit project, project internal and shared. Each system has essential features and limitations.
Project Internal Every Revit project has an internal coordinate system referred to in several places as project internal. The origin of this coordinate system is at first marked by a project base point; however, this reference point can be moved away from the internal origin. We discuss the project base point in greater detail later in this chapter.
The project internal coordinate system cannot be changed, and your model should be constructed within a one-mile radius of the internal origin. The true origin in Revit is referred to as the Project Start Up Point, and the project base point can be reset to this point by setting it to Unclipped, right-clicking the icon, and selecting Move To Startup Location.
A complementary component of the project internal coordinate system is the view orientation of Project North. This setting is the default and can be found in the View Properties of any plan. We strongly recommend that your model be created in an orthogonal relationship to the project or as you expect the plans to be oriented on a typical sheet. Your project’s actual relation to true north will be established via shared coordinates.
Shared Coordinates In simple terms, shared coordinates are just a way for the project team to use the same work point. In other words, the shared coordinate system consists of a single origin and true north orientation that can be synchronized between models and even Autodesk® AutoCAD® drawings. In the diagram shown in Figure 6.4, you can see an architectural model and structural model linked together. Each model was created using a different project internal origin (not the recommended method), but their shared coordinates were synchronized.
When you attempt to synchronize shared coordinates between linked projects, there are two tools to achieve this: Acquire Coordinates and Publish Coordinates. A simple way to understand the difference between these tools is to think of them in terms of pulling versus pushing:
It is important to understand the situations in which you would pull or push coordinates between linked files. A typical workflow for establishing a synchronized, shared coordinate system on a single building project is as follows:
For a campus-style project in which you might be creating multiple instances of a linked building model, you would most likely use Publish Coordinates to push information from a site model into the linked building model. Here is how that would work in a hypothetical scenario:
Revit provides two graphic objects to identify the project base point and the survey point. In the default templates, these points are visible in the floor plan named Site; however, they can also be displayed in any other plan view by opening the Visibility/Graphic Overrides dialog box, selecting the Model Categories tab, and expanding the Site category, as shown in Figure 6.6. You can also use the Reveal Hidden Elements command in the view control bar to temporarily display these points.
Project Base Point The project base point (PBP) is a reference point that is usually located at the origin of the internal project origin. The PBP is used to define a common reference for project-specific annotation such as spot coordinates. The PBP cannot be used for exporting your project to CAD or Navisworks® formats. The only choices you have for exporting are Internal or Shared. Remember, the internal project coordinates cannot be modified, but you can move the PBP. Let us review what the paper clip icon means when you need to relocate the base point.
The unclipped PBP can be moved in relation to the internal origin, thus creating a secondary reference point for spot coordinates, spot elevations, and levels—as long as the measuring parameter (either Coordinate Origin or Elevation Base) is set to Project Base Point in the respective type properties of such annotation elements. Moving the clipped PBP icon is the equivalent of using the Relocate Project tool, moving the project relative to the shared coordinates system.
Unless your project requires the use of a secondary point of reference other than the survey point, we recommend that you do not adjust the PBP and that you make sure your building model lies within a close reference of this point, such as the corner of a property line or intersection of column grids A and 1.
Survey Point The survey point (SP) is the equivalent of a station pin or geodetic survey marker in a civil engineering drawing (Figure 6.7). This is the point that will be coordinated to real geospatial coordinates. For coordination with Autodesk® Civil 3D® software, the SP is used when a Revit project is exported to the ADSK file format.
Specifying a particular location for the SP based on civil engineering data is not a requirement. For smaller projects, the SP and shared coordinates may never be used at all; however, they are critical in the use of analytical tools for daylighting and solar analysis.
To further expand your understanding of these points and what happens when they are modified, we created a sample file for your reference. Open the file c06-Shared-Points.rvt
from this book’s web page (www.sybex.com/go/masteringrevit2017). In this file you will find three copies of the Level 1 floor plan. One view is configured to display the project coordinates, another view displays the shared coordinates, and the third view displays a combination of the two. There are also two types of spot coordinates: one indicating project coordinates in which the values are prefixed with the letter p and the other indicating shared coordinates with the prefix of s. You can open these three floor plans and tile the windows (click the View tab, select the Window panel, and choose Tile, or type the keyboard shortcut WT) to get a better sense of how these points affect one another (Figure 6.8).
In this sample file, you can explore the effects on your model’s coordinates of moving the project base point and survey point. When selected, the project base point and survey point have paperclip icons that determine the behavior of the points when you move them. Clicking the paperclip icon changes the state from clipped to unclipped and back to clipped.
The following list shows the possible point modifications and how they affect the project. In most cases you should not have to move the project base point or survey point if you are using a linked Civil 2D or 3D file and acquiring the coordinates from the linked file.
Model elements “move” relative to shared coordinates.
Moving a clipped PBP is the same as using Relocate Project—that is, the model elements maintain their relationship to the PBP, but the relationship of the PBP to the survey point is changed.
Model elements do not move.
Unclipping the PBP essentially detaches it from the internal project origin. Moving the unclipped PBP is only used to affect the values reported in spot coordinates set to the project origin base. It does not have any effect on exported files.
Model elements do not move.
The clipped SP represents the origin of the shared coordinate system. Moving it is the equivalent of setting a new origin point. Use caution if you must move the shared coordinates origin if linked models already exist in which the shared coordinates have already been synchronized. In such a case, each linked model must be opened and manually reconciled with the model in which the origin has changed.
Model elements do not move.
Moving an unclipped SP essentially does not do anything. It does not affect spot coordinates, and it does not affect the origin of exported files.
Linked Revit models use what we will call a portability setting that is similar to the way Xrefs are handled in AutoCAD. Although this setting is not exposed when you initially link a Revit model, you can modify the setting by switching to the Insert tab and selecting Manage Links. Change the setting in the Reference Type column as desired (Figure 6.9). If you are using linked Revit models where one or more of the project files have worksharing enabled, there are a few guidelines to follow as well as some tangible benefits, such as linked visibility control between worksets. Be sure to read more about worksharing in Chapter 5, “Working in a Team,” before continuing with this section. When you are linking worksharing-enabled files from consultants, you will first need to decide if you need to maintain the worksets in the linked files. Even though you may not have direct access to your consultants’ servers, the software will attempt to reconcile the location of each project model’s central file location. We recommend handling each received project file using one of the following options: If your team decides to disable worksets in linked files received from consultants, you will avoid any problems related to the central file not being found; however, you will not be able to extend workset visibility settings into the linked files or use worksets to selectively load content from the linked model into your host project. If you preserve worksets, you can continue to use worksets in the linked model to your advantage. For example, when you first link a worksharing-enabled model into your project, you can use the Specify option associated with the Open button in the Import/Link RVT dialog box, as shown in Figure 6.11. At any time throughout the development of the project, you can adjust the loaded worksets from linked files very easily. From the Manage tab or the Insert tab in the ribbon, click the Manage Links button. In the Manage Links dialog box (Figure 6.12), select one of the linked RVT files, and if it is a worksharing-enabled file, click the Manage Worksets button to open the Worksets dialog box. We describe this process in greater detail in the next section of this chapter. In addition to the workset-loading control, you can apply visibility settings automatically to linked models—as long as the worksets in any linked files are named exactly as they are in the host file. For example, if you linked a model that had the default workset named Shared Levels and Grids, and your host model also had that same workset, you can hide the workset in both the host and linked model in one step. Open the Visibility/Graphic Overrides dialog box, select the Worksets tab, and then set Shared Levels and Grids to Hide. You will see that any datum objects assigned to that workset—in either the host or linked model—are hidden. You do not need to perform a separate visibility override on the linked file. Although the automated visibility linking of worksets can be beneficial, it can also be problematic when you need to coordinate content between the host and linked models. In the same scenario described previously, what if you wanted the Shared Levels and Grids workset to be visible in the host model but hidden in the linked model? This is common when you are coordinating datum objects between architectural and engineering models. The grids and levels from a linked model should be visible for use with the Coordination Monitor tools described in this chapter, but then the linked references might need to be hidden. In this case, you might choose to access the Manage Worksets button discussed earlier and close the Shared Levels and Grids workset in the linked file. You could also adjust the linked view; however, this would require you to adjust every view in which the linked model appears. We discuss linked views in greater detail in Chapter 17, “Documenting Your Design.”COMPARING ATTACHMENT TO OVERLAY
LINKING WITH WORKSHARING FILES
As we discussed in Chapter 5, we recommend that you create and reserve a workset for each linked Revit model, such as Link-RVT-Structure or Link-RVT-HVAC. This simple step will allow your team members to choose whether they would like any, all, or none of the linked models to be loaded when working on a host model. To enable this functionality, use the Specify setting in the drop-down options next to the Open button.
When the Worksets dialog box appears, select the worksets reserved for the linked models and set their Open/Closed status as you desire. The benefit of using worksets to manage linked Revit models is the flexibility it offers a project team. When a team member closes a workset containing a linked model, the linked model is unloaded only for that person—it does not unload for the entire team.
Additional flexibility can be leveraged with the Workset parameter in both the instance and type properties of a linked model. In a large and complex project that consists of multiple building elements where some of the elements are identical, each may consist of multiple linked models: architecture, structure, and MEP. Figure 6.13 shows a simplified representation of such a design where the Podium has one set of models and Tower A and Annex are identical to one another, as are Tower B and the Penthouse.
In Figure 6.13, there are three Revit models that represent the podium and the two towers (A and B) for each discipline (Arch1, Arch2, and so on). There are multiple instances of several of the linked models. For each instance of a linked model, you can specify the Workset parameter so that the workset instance property represents the building element, and the type property reflects either the entire discipline or one of the discipline models, as in this example:
Using this example, you can choose to open the Tower A workset, which would load all the discipline models but only for Tower A, or you could choose to open the Link-Architecture workset, which would load only the architectural models but for all the building elements. You can modify the workset-type properties only after placing a linked model in your project. Access this setting by selecting an instance of a linked model and opening the Properties palette, and then click Edit Type. Although this functionality can offer a variety of benefits to your project team, it should be used with care and proper planning because it can adversely affect model visibility if you are using worksets for visibility manipulation.
Worksharing-enabled linked models also afford you the flexibility to adjust the visibility of project elements for the entire project, without relying on individual settings per view or maintenance of view templates. For example, grids and levels are not usually displayed from linked models because their extents are not editable in the host model and the graphics may not match those in the host model. Without worksets, the owner of the host model would have to establish visibility settings for the linked model within all views and hopefully manage those settings in view templates. Assuming the owner of the linked model maintains the levels and grids on an agreed-upon workset such as Shared Levels and Grids, you will be able to close that workset in one place, thus affecting the entire host project. To modify the workset options for linked Revit models, follow these steps:
Let us review some of the benefits and limitations of using linked Revit models. You should carefully consider these aspects not only when preparing for interdisciplinary coordination but also when managing large, complex projects with linked files.
The following list highlights some of the benefits and limitations:
The following list highlights some of the limitations:
Before you begin the exercises in this chapter, download the related files from this book’s web page. The project files in each section’s exercise should be saved because the lessons will build on the data. In this first exercise, you will do the following:
The structural model is essentially a blank project with a few element types specifically built for this chapter’s lessons. Let us get started working with shared coordinates:
c06-1-Structure.rvt
or c06-1-Structure-Metric.rvt
and activate the Level 1 floor plan.Switch to the Insert tab and select Link Revit.
On the Revit tab of the Manage Links dialog box, click the Add button to add a new linked model. To make the steps easier to follow, the rest of this chapter will use the Link Revit button on the Insert tab, but both buttons will give you the same result.
c06-2-Architecture.rvt
or c06-2-Architecture-Metric.rvt
.Activate the South elevation view and use the Align tool to bring the linked model’s Level 1 down to align with Level 1 in the host model if necessary.
Remember, linked models should be aligned to the geometry in the host model. The modeled elements in the host model should be as close to the internal project origin as possible.
Switch to the Manage tab, and from the Project Location panel, select Coordinates ➢ Acquire Coordinates. Pick the linked model.
The elevation value displayed in the level within the host file has changed to match the shared elevation in the linked file. This is because the Elevation Base parameter of the level’s type properties has been set to Survey Point.
Once you have linked one or more Revit files into your source project file, you may want to adjust the visibility of elements within the linked files. By default, the display settings in the Visibility/Graphic Overrides dialog box are set to By Host View for linked files, which means model objects in the linked files will adopt the same appearance as the host file. In the following exercise, we will show you how to customize these settings to turn the furniture off in the linked file and then display the room tags:
Go to the View tab in the ribbon, locate the Graphics panel, and select Visibility/Graphics. In the Visibility/Graphic Overrides dialog box, select the Revit Links tab.
You will see the linked architectural model listed as an expandable tree. Click the plus sign next to the name of the linked file, and you will see a numbered instance of the link. This allows you to customize the visibility for each instance of a linked file if you have multiple copies of the link in the host file.
In the row displaying the name of the linked file, click the button in the Display Settings column that is labeled By Host View.
Doing so opens the RVT Link Display Settings dialog box.
You should observe that all the furniture and casework from the linked architecture file are no longer visible in the Level 1 floor plan. In a standard architecture-to-structure collaboration scenario, the structural engineer is likely to have a view template in which typical architectural elements are already hidden. In such a case, the default By Host View settings would be sufficient. The previous exercise illustrates a scenario where additional visual control is required.
Whereas the previous exercise focused on the display of model elements, a slightly different approach is required to use annotation elements from a linked file. In the following exercise, we will show you how to display the room tags from the linked architectural model. Many other tags can be applied to linked model elements. Here are the steps:
After completing these steps, you should see the room tags from the linked architectural file in the host file. Remember that you can tag other model elements in linked files. Try using the Tag By Category tool to place some door tags on the linked architectural model.
Once you have established the configuration of linked Revit models for your project, the next step is to create intelligently bound references between specific elements within the models. In the past, CAD users might have referenced files containing grid lines or level lines to establish a level of coordination between one user’s data and another’s. These elements in CAD are merely lines—not datum objects as they are in a Revit model. If these referenced elements were modified in a CAD setting, the graphic appearance of the referenced lines would update, but there would be no additional automated response to the geometry. It would be the responsibility of the recipient to update any referring geometry in their host files.
The coordination tools in Revit—Copy/Monitor and Coordination Review—allow a project team to ensure a high degree of quality control while achieving it at an increased level of productivity. These tools can function on datum (levels and grids) as well as model elements such as columns, walls, floors, and fixtures. The Copy/Monitor command is used first to establish the intelligent bonds between linked elements and host elements, whereas the Coordination Review command automatically monitors differences between host and linked elements that were previously bound with the Copy/Monitor command.
Although these tools are indeed powerful and have no similarities to CAD workflows of the past, it is important to employ proper planning and coordination with your design team. The familiar adage of “quality over quantity” holds true for the implementation of coordination tools. It may not be necessary to create monitored copies of all structural elements within the architectural model. How would these affect project-wide quantity takeoffs for the sake of minor improvements in graphic quality?
We reiterate the necessity of developing a BIM execution plan to determine important aspects of the collaboration process. When using specific coordination tools such as those in Revit, teams might plan on issues such as these:
A seemingly powerful BIM tool will not replace the need for professional supervision and the standard of care implicit to respective disciplines in the building industry. Thus, there is no substitution for the most important part of effective collaboration: communication. Without open and honest communication, the coordination tools will discover conflicts, but the results may be ignored, dismissed, or overwritten, to the detriment of the team’s progress.
The Copy/Monitor command allows you to create copies of linked elements for better graphic control of the elements while maintaining an intelligent bond to the linked elements. If the linked element changes in a subsequent iteration of the project file, the changes are detected in the Coordination Review tool, which we will discuss next.
With the structural model saved from the “Using Linked Models” exercises, switch to the Collaborate tab and select Copy/Monitor ➢ Select Link. Pick the linked architectural model, and the ribbon will change to Copy/Monitor mode. Click the Options icon to open the dialog box shown in Figure 6.16.
As shown in Figure 6.16, the Copy/Monitor Options dialog box in Revit is divided into five tabs representing the elements available to be copied and/or monitored. For each element tab, there is a list called Categories And Types To Copy. As shown in Figure 6.17, the Floors tab lists the available floor types in the linked model in the left column and host model floor types in the right column. Notice that any of the linked types can be specified with the option Don’t Copy This Type. This feature can be used for quality control if your project’s BIM execution plan states that certain elements are not to be copied. For example, if walls are not to be copied, switch to the Walls tab and set all linked wall types to Don’t Copy This Type. You can also use the option Copy Original Type if the element type exists in the linked file but not in the host file. After one or more of these elements are selected using Copy/Monitor, the type mapping will be synchronized.
At the bottom of the Copy/Monitor Options dialog box, you will find a section called Additional Copy Parameters for each element tab (refer to Figures 6.16 and 6.17). The additional parameters are different for each element category. For example, when levels are copied and monitored, an offset and naming prefix can be applied to accommodate the difference between the finish floor level in a linked architectural model and the top-of-steel level in the host structural model.
Let’s take a closer look at each of the element category options available for the Copy/Monitor tool:
Levels In most cases, the difference between the location of a structural level and an architectural level may lead to the presumption that you would not want to copy levels between files. However, maintaining an offset between linked and host levels can be quite desirable. Keep in mind that the offset will apply to all copy/monitor selections. Thus, if a structural level needs to be offset by a different value, create the level in the host model and use the Monitor command to create the intelligent bond to the linked model’s level. The difference will be maintained through any modifications in the linked model.
Grids Copying the grids is usually a strong workflow. You can use the options on these tabs to convert the grid bubbles used by the architect into those used by the structural engineer. It is also possible to add a prefix to the grid names. For instance, you could add the value S- in the prefix field, and then grid A from the architectural model will come into the structural model as S-A.
Columns The structural engineer can choose to replace any column—architectural or structural—in the architectural model with an appropriate structural column; however, this implies that the architect will maintain an understanding of where differentiating column types would exist. Realistically, the structural elements should exist only in the structural engineer’s model and then link into the architectural model. The architect may then choose to either copy/monitor the linked structural columns with architectural columns (which act as finish wrappers) or place architectural columns along the monitored grid lines. In the latter option, architectural columns will move along with changes in grid line locations but will not update if structural columns are removed in the linked model.
Walls and Floors Similar to columns, structural walls that are important to the coordination process may be better managed in the structural model and linked into the architectural model. If you decide to use a copy/monitor relationship for these types of elements, it is best to create uniquely named wall types for structural coordination. Name such wall types in a manner that makes them display at the top of the list in the Copy/Monitor Options dialog box. You can do so by adding a hyphen (-) or underscore (_) at the beginning of the wall type name.
Finally, make sure you select the check box Copy Windows/Doors/Openings for walls or Copy Openings/Inserts for floors so that you also get the appropriate openings for those components in the monitored elements.
Continue with the structural model saved in the previous exercise in this chapter. In this exercise, you will do the following:
These steps will establish the intelligent bonds between elements in the host file with the related elements in the linked model. With the structural model open, activate the South elevation view. Then follow these steps:
Set all other entries under Original Type to Don’t Copy This Type.
Remember that you can select multiple rows in the Categories And Types To Copy list by pressing the Shift key while selecting a range of rows. You may then make a selection in the New Type column for any row, and all the selected rows will be modified.
In the Additional Copy Parameters section, set the following option:
Select the Level 2 and Roof levels in the linked model. Levels in the host model should be created 6” (150 mm) below the linked levels with the prefix T.O.S. (Top Of Structure).
There is already a Level 1 in the host model. You will need to use the Monitor tool to establish a relationship to the Level 1 in the linked model.
From the Copy/Monitor tab of the ribbon, choose the Monitor button and select Level 1 in the host model.
You can only select levels in the host model for the first pick.
Select Level 1 in the linked model to complete the monitored relationship.
You will see an icon appear near the midpoint of the level indicating that it is now monitoring the level in the linked model.
If you now select any of the grids or levels in the host file, you will see a monitor icon near the center of the element. This icon indicates that the intelligent bond has been created between the host and the linked element and will evaluate any modifications in the linked file whenever the file is reloaded.
Save and close the structural model and then open the architectural model, c06-2-Architecture .rvt
orc06-2-Architecture-Metric.rvt
. Using the procedures you have learned in this chapter, link the structural file into the architectural model. Placement should be done in the Level 1 floor plan using Auto – By Shared Coordinates positioning.
Use the Copy/Monitor tools in Monitor mode to establish the relationships of the grids between host and linked models. Doing so will ensure that changes to grids in either model will be coordinated.
After intelligent bonds have been established between elements in linked models, it is the purpose of the Coordination Review tool to support the workflow when datum or model elements are modified. This tool was designed to allow the recipient of linked data to control how and when elements in host models are modified based on changes in the linked models.
When a linked model is reloaded—which will happen automatically when the host model is opened or when you manually reload the linked model in the Manage Links dialog box—monitored elements will check for any inconsistencies. If any are found, you will see a warning message that a linked instance needs a coordination review.
The Coordination Review warning is triggered when any of the following scenarios occur:
To perform a coordination review, switch to the Collaborate tab and click Coordination Review ➢ Select Link. After picking one of the linked models, you will see the Coordination Review dialog box, which lists any inconsistencies in monitored elements (Figure 6.18).
For each of the changes detected in the Coordination Review dialog box, one of the following actions can be applied. Actions that result in changes to elements will be applied only to the host model; they do not modify elements in a linked model. Also, not all options are available for all monitored elements.
As you can see, Coordination Review can be a powerful tool to support the collaboration process. Remember that such a tool may not be appropriate for all elements at all times. For example, instead of copying and monitoring columns and grids, it may be sufficient to copy and monitor only grids because the columns placed in your host model will move with the grids anyway.
In this exercise, you will use two files that have already been linked together with monitored elements between both files. You can download the files c06-Review-Arch.rvt
or c06-Review-Arch-Metric.rvt
(architectural model) and c06-Review-Stru.rvt
or c06-Review-Stru-Metric.rvt
(structural model) from this book’s web page. In this exercise, you will do the following:
Remember that you cannot have a host model and a linked model open in the same Revit session. To make this lesson easier, you can launch a second Revit session. Open c06-Review-Arch.rvt
or c06-Review-Arch-Metric.rvt
in one session and c06-Review-Stru.rvt
or c06-Review-Stru-Metric.rvt
in the other. Then follow these steps:
In the previous exercise, you might have noticed the appearance of a monitored floor sketch. Why did a floor sketch change if you only moved a grid and renamed another? The answer lies in constraints and relationships. The exterior wall in the architectural model was constrained to be 2’-0” (600 mm) offset from grid line F. When it was moved, the exterior wall was moved to maintain the offset. The sketches of the model’s floor slabs were created using the Pick Walls tools, creating an intelligent relationship to the wall. The modified grid affected the wall, which modified the floor, and the Coordination Monitor tools ensured that all changes were detected and presented to you for action.
In addition to asset management, digital fabrication, and cost estimation, 3D coordination is one of the most important uses of building information modeling. It has enormous potential to reduce the costs of construction through the computerized resolution of clashing building elements as well as exposing opportunities for alternate trade scheduling or prefabrication. The key component to achieving 3D coordination is interference checking, also known as clash detection.
The Interference Check tool is a basic tool supporting 3D coordination. You can use it within a single project model or between linked models. You can also select elements prior to running the tool in order to detect clashes within a limited set of geometry instead of the entire project.
For more powerful clash-detection capabilities, Autodesk offers Navisworks® Manage (www.autodesk.com/navisworks), which is a multiformat model-reviewing tool with various modules supporting phasing simulation, visualization, and clash detection. Figure 6.19 shows an example of a model in Navisworks Manage comprising Revit, Tekla Structures, and AutoCAD MEP components. Some of the benefits of using Navisworks for interference-checking over Revit include automated views of each clash, grouping of related clashes, enhanced reporting, clash-resolution tracking, and markup capabilities. Revit models can be opened directly in Navisworks or exported directly to the Navisworks format from the Application menu.
Let’s take a look at the Revit interference-checking process. For this exercise, you will need to download three sample files to your computer or network: c06-Interference-Arch.rvt
, c06-Interference-Mech.rvt
, and c06-Interference-Stru.rvt
. You can download these files from this book’s web page. The sample files are already linked to each other using relative paths, so be sure to place all three files in the same folder. Then follow these steps:
c06-Interference-Mech.rvt
and activate the default 3D view.c06-Interference-Stru.rvt
from the Categories From drop-down list in the left column. Select Structural Framing in the left column and Ducts in the right column (Figure 6.20).You can navigate in the 3D view using any method (mouse, ViewCube®, or SteeringWheels®) while keeping the interference report open. This facilitates resolution of the clashing items. The results of the interference check can also be exported to an HTML format report. Click the Export button and specify a location for the report. You can then share this report with other members of your design team for remedial actions on linked models.
Prepare for interdisciplinary collaboration. Proper planning and communication are the foundation of effective collaboration. Although only some client organizations may require a BIM planning document, it is a recommended strategy for all design teams.
Master It What are the key elements of a BIM execution plan?
Collaborate using linked Revit models. The most basic tool for collaboration is the ability to view consultants’ data directly within the context of your own model. Project files from other disciplines can be linked and displayed with predictable visual fidelity without complex conversion processes.
Master It How can worksharing complement the use of linked Revit models?
Use Copy/Monitor between linked models. The Coordination Monitor tools establish intelligent bonds between elements in a host file and correlating elements in a linked model. They also support a workflow that respects the needs of discrete teams developing their own data, perhaps on a different schedule than that of other team members.
Master It How can grids in two different Revit projects be related?
Run interference checks. Interference checking—also known as clash detection—is one of the most important components of building information modeling. It is the essence of virtual construction and has the greatest potential for cost savings during the physical construction process.
Master It How do you find interfering objects between two linked Revit models?