Sharing the Work in Revit

Worksharing Vocabulary

In order to understand worksharing, let's first get acquainted with its basic terminology.

Central File: A master project database repository containing all building model data subdivided into logical areas created and saved in a shared location on a network so that more than one person can work on that project.

Local File: A copy of the Central file saved on a project team member's workstation or network location. This local file acts as an interfacing mechanism for working on the Central file.

Workset: A collection of elements that can be edited by only one team member at a time.

Element Borrowing: A process that allows a team member to edit an element with or without checking out a Workset. Element borrowing happens automatically when a team member selects an element for modification contingent on the fact that the object is not owned or borrowed by another team member. Objects owned by other team members will not be open for borrowing.

Editing Requests: When elements are modified by another team member, that person retains editing ownership of those elements. Therefore, when another team member wants to edit an owned element, they must submit a request to the owner for rights to edit it.

How Worksharing Works

The basic process of worksharing is outlined in these steps.

1. A single user creates a project and begins creating the initial geometry and information. The building information model is developed to a certain point.

2. Then, additional users are required and worksharing is enabled in the project.

3. Revit automatically assigns the various elements of the project to logical Worksets.

4. The file is then saved as the Central file to the network appending the project file name with "-central" for clarification.

5. Team members will then save the Central file as a Local file to their local hard drive or on the network and append the file name with an identifier such as "-bknittle" for clarification.

6. Additional Worksets can be created in a user's Local file to group the building elements into logical groupings.

7. Users make modifications by using Element Borrowing or checking out a Workset through their Local file. Element borrowing in a Workset checked out by another team member can be made through Editing Requests.

8. Each team member makes regular Local file saves and also saves to the Central file throughout the day.

9. Each team member makes regular reloads from the Central file to synchronize their own Local file.

10. Users with checked out Worksets can relinquish ownership at any time.

This workflow is described in more detail in the rest of the tutorial.

Beginning the process

1. Click on the Workset button on the Workset Toolbar. (It can also be accessed from the File pull-down menu.)

NOTE: There is no going back once Worksharing is enabled.

2. The Worksharing dialog will appear. The dialog prompts the user for a name to the shared levels, grids, and generic workset that will contain default model objects. These default names are a good start, therefore they need not be renamed unless necessary. Select OK when ready.

3. The Worksets window dialog will appear, allowing the user to view existing Worksets or create additional Worksets. The elements can be viewed all at once or filtered in the Show category. These Worksets are the User-Created, Families, Project Standards, and the Views Worksets. These different types are briefly described below.

Default Workset:

• Views: For each view, a dedicated view workset is created automatically containing the view's defining information and any view-specific elements such as annotation.
  
  
• Families: A family workset is created for each family defined in the project.
  
  
• Project Standards: Each project setting is placed on its own workset. These standards include Materials, Line Styles, etc.

User-Created Workset:

• Shared Levels and Grids: At the onset of enabling worksharing, this workset is automatically created for existing grid and level objects.
  
  
• Workset 1: Everything that is left over is placed into this workset.

Create the Central File

1. Doing a File > Save As will create the Central File. Best practices recommend that the Central File be given a name followed by "-central" then saved to a shared network location. This will allow the additional team members to copy it locally or on the network. Click the Options button.

2. The check box for Make this the Central location after save will be checked after worksharing is invoked.

3. In the File menu, select Relinquish all Mine. This will relinquish all the Worksets that were created so that they can then be accessed by the rest of the team.

Create the Local Files

Each team member will open the Central File and perform a File > Save As. Best practices recommend that the Local File be given the same project name followed by "-[Login Name]" and save it to their local hard drive. A virtual link is created by Revit that connects the two files.

NOTE: Some project leaders actually create the Local Files for the team and save the Local Files on the network for back-ups. Users then open their specific Local Files. Verify network speed. The Central File should not be opened beyond this point.

Benefits of Worksets:

• Large projects can be broken down into manageable areas.
  
• Each team member can be assigned a Workset giving them sole responsibility of that portion of the work.
  
• When opening a project, the user can specify which Workset to open.
  
• Disciplines can work independently from one another by creating discipline specific Worksets within the same project (typical in an AE firm).
  
• Visibility of a Workset can be controlled per view.

Limitations of Worksets:

• Regular saves to Central and reloads from Central need to be coordinated manually to keep the team and Central file in sync.
  
• Editing Requests must be acknowledged, both verbally and electronically.
  
• Anybody can create a Workset.
  
• Have to relying on team members to relinquish all Worksets at the end of the day to ensure the project still moves forward, even those going on vacation or falling ill.

Considerations when creating Worksets:

• The project size.
  
• The size of the project team.
  
• The team member's role (modeling or drafting, Architectural or MEP, etc.).
  
• Carefully planning with the team how the building model will be assigned and broken down into simple and logical Worksets.

Create Worksets

1. Click the Workset button on the Workset Toolbar. This will launch the Workset dialog window.

2. In the Worksets dialog window select the New button. This will launch the New Workset dialog window.

3. Give the new Workset a name that describes what elements will be assigned to it. This will prevent any confusion. Check the Visible by default in all views box. This will give the Workset the most flexibility.

NOTE: Creating a Workset will automatically make the user who created it the owner.

4. Open a view to work in. Plan or 3D views work really well for moving objects to a Workset. Select common objects (walls, doors, windows, etc.) and on the Options Bar select Properties, or Right Mouse Click to select Properties. In the Element Properties dialog window under Instance Parameters, find Identity Data. Find the parameter Workset. Activate the cell's flyout and select the new Workset.

5. Continue this procedure to create and assign elements to additional Worksets.

Saving Local, Saving to Central, and Reload Latest

It is very important to have a well regimented plan when it comes to worksharing. The times for doing project saves and updates during the day should carefully be selected so as to not disrupt the project workflow, for example, during lunch break or prior to leaving for the night.

1. Saving the Local File can be accomplished by either clicking the Save button on the Standard Toolbar, going to File > Save, or the command alias Ctrl+S. All three options execute the save command.

2. Saving to Central can be accomplished one of two ways. The first method involves the Save to Central button on the Standard Toolbar. This command updates the Central File with recent changes. However, it does not return the user-created Workset. The preferred method is using File > Save to Central. This will provide the user many more options when executing the command. The File Save As dialog window will be launched.

3. In the File Save As dialog window, the user can relinquish any owned Workset, as well as save their own Local File. A Comment field is provided for specifics.

4. Synchronizing the project can also be accomplished in many ways. File > Reload Latest is one method of updating the Local File. The command alias RL is also available when synchronizing.

Working in a Shared Environment

Modifying elements in a Workset checked out by you is one story. However, if that element happens to be of a Workset which is not owned or owned by another user, modification will require element borrowing.

Element Borrowing occurs when a modification is made to an element(s) that is not owned by you. A small icon resembling a puzzle piece with a line through it is displayed to signify that it is locked.

Two things will happen at this point. The user will click the puzzle piece and:

1. The user will click the icon and the element(s) will be free for editing. This occurs when an element(s) is part of a Workset that is not checked out or owned.

2. The user will click the icon and a warning will appear flagging the object as being owned by another user. You will then be given the choice to place an Editing Request.

Editing Requests are delivered via Revit from the requesting user to the receiving user.

1. The requester will click the Place Request button to alert the owner electronically and then call, IM (instant messaged), or email the other user. The requester can wait a minute and Check Now to see if his request was granted or Continue to work while the request is answered.

2. The owner of the element will receive a call, IM, or email and click the Editing Requests button on the Workset Toolbar.

3. This will launch the Editing Requests dialog window displaying all pending requests from other team member(s). The owner will either click the Show button to see the element(s), click the Grant button to allow the requester to borrow the element, or click the Deny/Retract button to disallow the borrowing of the element(s).

4. If the requester waited and clicked Check Now, Revit relays the granted request from the owner.

5. If the requester clicked Continue, the owner either called, IM'd, or emailed the response. But if that did not occur, the requester could simply click the Workset button on the Workset Toolbar and view the Borrowers column to see if the request has been granted.

NOTE: Editing Requests still require a measure of verbal communication outside of Revit to acknowledge or confirm a request for modification. Once a request has been granted, it will no longer appear in the Editing Requests dialog windows of all parties.

Improving the Performance of Worksharing in Revit

Projects tend to take on a life of their own, sometimes often leading to increased file size which can really slow performance. Revit offers the ability of selectively open the project through its Worksets.

A user will begin the process of opening a project either through File > Open, the Open button, or the command alias Ctrl+C. In the Open dialog window under Open Workset, several options are available as to how the project is opened.

• All opens all the Worksets of the project.
  
• Editable opens all Worksets checked out by you.
  
• Last Viewed opens the Worksets that were opened when the project was last closed.
  
• Specify opens the Workset selected from a list in the Opening Worksets dialog window shown below.

Visibility of Worksets

A prominent benefit of Worksets is having the ability to control its visibility settings, whether it is On or Off or grayed out for clarity.

Gray Inactive Workset Graphics is an option that can be activated from different locations: clicking the Gray Inactive Workset Graphics button on the Workset Toolbar, or by check box in the Workset dialog window.

Visibility Graphics provides an additional tab called Worksets which turns the visibility of all elements in a Workset on or off. Simply access it by Right-Mouse-Clicking in the view, going to View > Visibility Graphics, or using the command aliases VV / VG. Then select the Worksets tab. Finally check the box(es) to view the Workset(s) or uncheck the box(es) to hide the Workset(s).

Additional Tips

Back-ups: When Worksharing is envoked, Revit automatically creates a back-up folder for the central and local files. The incremental back-ups are controlled by the Save As options.

New Releases or Builds: When a new release or build is rolled out, the IT manager or Project Leader needs to open the Central File and save it as the new version. Then the users can create Local Files from the new Central File and continue working.

Linked Data: External project data can be linked to Revit and assigned to a Workset for additional visibility control. Revit also creates a tab for Revit Links in the Visibility Graphics dialog window.

Detaching from the Central File: This will break the connection between the Local File and the Central File. This option is accessed by opening a Local File and checking the box for Detach from Central. Revit will explain what this process will do and request your approval before proceeding.

The Worksharing Roadmap

In conclusion, the steps described in this tutorial can be captured by the Worksharing diagram shown below.

Creating Phases

1. Click Settings menu Phases. By default, each project has phases called Existing and New Construction.
2. Click the number box adjacent to a phase.

   

3. Insert a phase.
4. You cannot rearrange the order of phases after you add them, so be aware of placement.

   To insert a phase before or after the selected phase, click Before or After.

   Revit MEP names the phases sequentially as you add them, for example, Phase 1, Phase 2, Phase 3, and so on.

5. If desired, click the Name text box for a phase to rename it. Similarly, click the Description text box to edit the description.
6. Click OK.

Combining Phases

1. Click Settings menu Phases.
2. Click the number box adjacent to the phase you want to combine with another existing phase.
3. Click either Combine With Next or Combine with Previous to combine phases.

When you combine phases, the phase that is selected is deleted; this means that all components that had that phase value for their Phase Created and Phase Demolished properties update to show the new combined phase value.

Phase Filters

A phase filter is a rule you can apply to a view to control the display of components based on their phase status: new, existing, demolished, or temporary.

Default Phase Filters

Each Revit MEP project contains the following default phase filters:

• Show All: Shows new, existing, demolished, and temporary components in that particular phase. Components demolished in earlier phases do not display.
• Show Complete
• Show Demo + New: Shows demolished and new components.
• Show New: Shows new components.
• Show Previous + Demo: Shows existing and demolished components.
• Show Previous + New: Shows existing and new components.
• Show Previous Phase: Shows all elements from the previous phase. Existing conditions are new to the first phase of the project, so using this phase filter may not display your intent.

NOTE:To show all elements from all phases, do not apply a phase filter to the view.

Phase Status

• New: Component was created in the phase of the current view.
• Existing: Component was created in an earlier phase and continues to exist in the current phase.
• Demolished: Component was created in an earlier phase and demolished in the current phase.
• Temporary: Component was created and demolished during the current phase.

Creating Phase Filters

1. Click Settings menu Phases.
2. In the Phasing dialog, click the Phase Filters tab.
3. Click New to insert a new phase filter. The filter is assigned a default name, click in the Filter Name box to edit the name.
4. For each of the phase status columns (New, Existing, Demolished, and Temporary) select how you want components to display by selecting one of the following options from the drop-down menu:
   • By Category: displays components as defined in the Object Styles dialog.
   • Overridden: displays components as specified in the Graphic Overrides tab of the Phasing dialog.
   • Not Displayed: does not display the component.

Applying Phase Filters

1. In the Project Browser, right-click the view to which you want to apply a phase filter, and select Properties.
2. In the Element Properties dialog, select a value for the Phase Filter instance parameter.
3. Click OK.

Defining the Graphic Display for Phase Filters

You define overrides to change the appearance of components in views with phase filters.

1. Click Settings menu Phases.
2. In the Phasing dialog, click the Graphic Overrides tab.
3. Click the appropriate boxes to define the appearance for new, temporary, demolished, and existing elements.

For the phases you want to have use the graphic override settings, select Overridden for the value on the Phase Filters tab.

Infill Element for Phasing

If an insert (such as a window) and its host (a wall) do not have the same values for the Phase Created and Phase Demolished properties, Revit MEP automatically places an infill element in the host to patch the hole created by the insert.

The infill element lets you place inserts from one phase, demolish them, and then place new inserts in the same location. The infill element assumes the same structure as its host. In certain cases you can modify the structure of the infill element by changing its type.

Infill elements for roofs and floors project down from the top face, and infill elements for ceilings project up from the bottom face.

You cannot drag, move, mirror, rotate, copy, or paste an infill element.

Infill Element for Earlier Phases

If you place an insert into a host in a phase later than the host's creation phase, Revit MEP creates an infill element for earlier phases.

For example, you have a roof that was created in Phase 1. You add a skylight to the roof in Phase 2. You look at the roof and skylight in a 3D view. If you set the 3D view's phase to Phase 1, an infill element replaces the skylight. You can view this infill element in a section view.

Infill Element for Demolished Components

When you demolish an insert in a host element, the insert becomes an infill element.

Demolished window becomes infill element

You can then place a new insert near the demolished insert.

New window placed near demolished window

If you apply a phase filter to the view that does not show demolished elements, such as Show Previous + New, you see only the new insert.

New window only

Revit Family Man: Anchors Aweigh

Revit Family Man: Anchors Aweigh

Text value Line Styles

Here is a quick tutorial on how to create line styles in Revit whereby you can change the text values. We use this for lines like Fence, Hot water, Cold water etc.









1. Start a new family - annotation symbol - generic annotation.
2. Delete the Red text warning.

3. Add a Label. Click mouse pointer at the intersection of ref Planes.












4. In the Select Parameter Dialogue box click Add.












5. In the Parameter Properties Dia Name Feild : Line Text Value.
6. Leave it as a text parameter, and group it under Text.











7. In the Select Parameter Dialogue box type a value of f ( at the bottom.)
8. Save this file.











9. Start a new family using the Detail component line based template.

10. Alt+Tab back to the symbol family(or pick in the window pull down)

11. Load the symbol into the detail line base new family.


12. Using the symbol tool place the symbol near the 1st end point of the line(on the left hand side.


















13. Using the align tool align and lock the symbol to the reference planes vertically as well as horizontally.

14. Sellect the symbol and cross associate the "line text Value" parameter through to the new family. ( hit the little inconspicious square box at the end of the paramters field, this will take you to the add parameter dialogue box. Ie follow steps 4-7 again)









15. select the symbol, now use array tool with the set the amount to 4 and tick last option and array the symol from the left to the right side.










16. Align and lock the last symbol as per step 13.

17. One could add an array parameter here or better yet, add an array formula that divides the line length by centers set up for the text.





18. Lastly draw a line style of your choice fom left to right.

19 Load into your project and using the detail component tool, set up all your fences and so on.

20. Edit duplicate change the name, change the text value (hot water) and off you go doing your water reticulation CD's

Autodesk Revit MEP: BIM for MEP Engineering

Revit MEP is the purpose-built building information modeling (BIM) software for mechanical, electrical, and plumbing (MEP) engineering. This white paper explores how key

concepts of BIM improve MEP design processes, both building mechanical and electrical, and how those processes are further enhanced when combined with Revit-based architectural and/or structural workflows.

Using BIM to Improve MEP Design
Today's demanding business environment is driving a push towards more efficiency and integration in building industry supply chains. Owners are demanding better built buildings for less money in less time. Architects, engineers and contractors are under pressure to streamline their building design and delivery process - searching for ways to improve productivity, lower costs, and deliver better-quality products.

The success of BIM for building design - as evidenced by the rapid adoption of BIM solutions like Autodesk® Revit® Building software - is redefining clients' expectations of their MEP consultants. Like BIM for building and structural design, BIM for MEP is a design methodology characterized by the creation and use of coordinated, consistent computable information about a building's MEP design - information used for design decision-making, production of accurate documentation, predicting performance, costestimating and construction planning, and, eventually, for managing and operating the facility.

Several key concepts of Revit Systems are fundamental to understanding how BIM impacts the MEP design process: the use of a computable building model, holistic design, and parametric change management.

Computable Building Model
Revit Systems features a computable building model – that is, a model in software that can be operated on by a computer as a building Using a conventional CAD system for design, MEP engineers and designers visualize the 3D design in their brain and transfer it to a 2D drafted representation. Some CAD systems fashioned specifically for MEP design allow the user to model the system geometry in 3D for the purposes of coordination and extracting drawings - making the model seem more intelligent than it really is. But because the model isn't computable, the elements and systems don't know how to interact with each other.

Whereas the Revit Systems building information model captures the functional relationships between building elements and systems. Walls, beams, ducts, pipes, distribution panels; they all "know" what they are, what they do and how to react to the rest of the building.

Holistic MEP Design
This computable Revit Systems building model enables a "holistic" design approach, i.e. MEP design done in the context of the whole building. For example, since the electrical and mechanical systems "know" about each other - an electrical engineer can track the power requirements of the mechanical equipment included in the design and have the software automatically configure electrical load requirements to dynamically change in mechanical equipment specifications.

This holistic approach unites not only the MEP disciplines, but the process as well - featuring an integrated digital environment for design, documentation and analysis. When used in conjunction with other team members using Revit-based design applications, this holistic approach expands to include the rest of the building as well.

Parametric Change Management
The majority of MEP engineering solutions today are based on CAD technology with a focus on the production of construction documentation rather than the engineering design itself. The drawings are either created directly, or extracted from a model. As the design evolves, a high level of effort is required to manage and coordinate the documentation and actionable building design data (such as schedule, cost, building performance, and so forth) of these CAD systems.

In contrast, Revit Systems is built upon a parametric change engine that provides immediate, comprehensive change propagation through the natural operation of the software. This results in the reliable, coordinated, and consistent design information and documentation that characterizes BIM.


Figure 1
Autodesk Revit Systems expands the scope of the Revit family of products, delivering a BIM platform for collaborative multidisciplinary building design. Image courtesy of Dal Pos Architects – Robson Woese Consulting Engineers.


MEP Design with Revit Systems

Design and Feedback
Revit Systems offers a unified environment for MEP design and engineering, analysis, and documentation. MEP engineers work directly in the model, and the drawings themselves are part of the building information model. Intuitive layout tools make system layout fast and easy. Engineers modify their design by dragging design elements to move or change them on the screen. The parametric change engine enables all model views and drawing sheets to update automatically whenever a change is made anywhere for accurate and coordinated designs and documents at all times.

Revit Systems features automatic sizing and systems layout tools, and provides engineers with immediate feedback on their design. For example, during the layout of a mechanical system, Revit Systems displays the critical flow of a mechanical system, allowing an engineer to modify the design for maximum performance and efficiency.

Figure 2
Revit Systems provides engineers with immediate feedback on their designs, such as displaying the critical flow path of a mechanical system (shown in the bottom view opposite).

Avoiding Interferences
Automatic interference checking during the design process is another valuable feature of Revit Systems. Typically, a building's architectural and structural systems are defined well in advance of its MEP systems, with only standard "rule of thumb" space allowances reserved for the latter. This sets the stage for inevitable conflicts between the area needed for those MEP systems and the overall cost of the building. In large building designs - such as hotels, high-rise apartment buildings, or intricate office complexes - squeezing the required MEP systems above the ceiling becomes particularly challenging.

The 3D modeling environment of Revit Systems helps the MEP designer overcome the challenges of fitting the required components into tight spaces, and then provides interference checking to detect collisions during the design process - reducing the risk of construction cost overruns.

Figure 3
Revit Systems provides interference checking to detect collisions during the design process.


Green Design
Revit Systems also supports key aspects of sustainable design by facilitating complex processes and analyses. For example, Revit supports export to gbXML for use in third party energy and heat load analysis applications. MEP engineers can use the information created in their computable Revit Systems building information model to test the
performance of their design, eliminating the time-consuming task of transferring data manually.


BIM for Mechanical Design

Data-Centric Design
The data-rich, computable Revit Systems model is used to drive the MEP design process, with a host of tools to aid in the layout of mechanical ductwork and piping, and plumbing systems.

For example, Revit Systems enables users to perform many engineering calculations directly in the model; calculations like sizing mains, branches, or whole systems at a time, using industry-standard methods and specifications (such as the ASHRAE fitting loss database). System sizing tools are integrated with the layout tools and instantly update the size and design parameters of duct and pipe elements - without file exchanges or thirdparty applications.



Figure 4
Revit Systems enables duct sizing directly in the model during layout.


Revit Systems automatically provides duct and pipe routing solutions between any two points. The routing path is constrained by the engineer, who selects fitting or connection preferences to meet specific design criteria. The software then finds and displays multiple routing paths - allowing the engineer to choose the option that works best for a design.
During the layout of the plumbing design, a user just defines the rise over run and the software automatically calculates invert elevations according to industry codes and tags them at the ends of pipe runs - minimizing the guesswork and manual calculation on sloped pipe. The software also automatically places all plumbing risers and drops - reducing the tedious aspects of system modeling.


Figure 5
Revit Systems automatically provides
routing solutions based on predefined duct preferences. To view routing solutions, the user selects any duct system component to identify the system and the software displays a series of temporary duct routing graphics (shown here in red).




Figure 6
The user then views the various solutions for routing the ductwork, using arrow buttons to scroll back and forth through the solutions, and clicks Finish to select a specific solution.

Design Insight
The computable Revit Systems building information model is also used to give the MEP engineer feedback as the design progresses.

Ducting or piping can be color-coded by a design parameter (such as low or high pressure, fluid service, velocity range, flow rate, etc). This "live" visual representation of design data gives engineers instant insight into the design intent for a particular system.

The System Inspector displays the critical flow path for a duct run and provides a quick method for viewing the design specifications for each duct segment in a system. This feedback allows an engineer to quickly identify areas of the system with the highest pressure loss and then modify the design to optimize system performance.

Figure 7
The System Inspector provides immediate design feedback.

As described earlier, Revit Systems detects clashes between any MEP system components (and when used in a Revit-based workflow, between architectural and structural elements from Revit Building and Revit Structure as well). Detection of interferences during the design process reduces costly field rework.

The computable model created by Revit Systems contains the necessary level of detail to enable direct engineering analysis. To facilitate that analysis, Revit Systems supports export via gbXML to industry leading gbXML third-party analysis applications, eliminating the manual transfer of data back and forth between modeling and analysis packages.

Increased Coordination
A major source of the mistakes and delays in building construction can be attributed to poorly coordinated design documents. In the Fifth Annual FMI/CMAA Survey of Owners - a 2004 survey conducted by FMI Corporation and the Construction Management Association of America (CMAA) - 70% of owners said they are seeing a decline in the quality of design documentation. For firms with slim profit margins, any rework costs exacerbate the bottom line - and MEP profit margins are notoriously slim (from 5% to 15% depending on the type of project).

A purpose-built BIM solution like Revit Systems automatically coordinates all design documentation - because views, drawings, schedules, reports and so forth are all "live" views of the same underlying database. The result is a dramatic reduction in documentation errors, producing an accurate design that requires less rework.

Revit Systems also allow the design and documentation of MEP systems to be done concurrently instead of serially, because project deliverables are created dynamically while the design work is being done. The production of design documentation requires less time and effort by the design team, increasing project throughput. In addition, a concurrent design and documentation effort tends to naturally increase project coordination, with team members working in real time on the execution of the design - minimizing the amount of information loss between participants.
Enhanced Communication
Revit Systems includes a variety of features that enhance project communication between team members, architects, clients, and contractors - including Revit Worksharing (described later in this paper), import/export features, and visual communication techniques.

During the design process, color-filled room plans can be used to visually communicate design intent. Rooms can be color-coded based on critical design parameters such as room types or airflow requirements. These color-filled plans are just another live view of the building information model and they update automatically whenever design changes are made.

Figure 8
Color fill plans in Revit Systems are a visual representation of design intent.

Revit Systems can export to, import from, or link with a variety of CAD formats - including DWG™, DWF™, DXF™, and DGN. This assures compatible data exchange with software applications - as well as clients, architects and partners. For example, 3D DWG files output from Revit Systems can be used in Autodesk® VIZ or Autodesk® 3ds Max® software to create photorealistic renderings of a building’s MEP engineering designs for enhanced communication with clients or team members. Similarly, DWF files output from Revit Systems can be used in Autodesk® Design Review software to facilitate the review process.

Figure 9
Revit Systems can quickly generate realistic rendered views of a building model.

Revit Systems can also read and write ACIS® solids, which gives users a way to import and export Revit Systems models to and from AutoCAD® or Autodesk® Architectural Desktop. This method can be used to cut sections and perform visual interference detection.

Finally, users can easily upload files from Revit Systems to an Autodesk® Buzzsaw® site for web-based collaborative project management. Added functionality even allows for automatic conversion of Revit Systems files to either DWG or DWF format.


BIM for Electrical Design
As explained earlier in this paper, a computable building model captures the functional relationships between building elements and systems. Architectural, structural and MEP elements all "know" what they are, how to interact with each other, and their role within a larger system. A computable building model is of particular importance for electrical design.

For the building mechanical design discipline, defining and understanding the physical relationships of building elements (i.e., the location, size and relationship between building components in 3D space) is as important as being able to model and get feedback on how the system functions (i.e., how much air flow should/can be delivered to a space and the pressure required to move that air through the ducts).

For the building electric design discipline, physical modeling takes a back seat to system modeling. Wires aren't actually routed in the model - that's left to the contractor on site. The only things physically modeled are electrical devices and equipment such as lighting fixtures, transformers, generators, panel boxes, etc., whereas system modeling is of the upmost importance. Are there any devices not assigned to a circuit? What is the number and types of circuits? Is there adequate power and light for the space to be used as intended?

These design considerations and calculations form the basis of the electrical engineer's challenge. The computable Revit Systems model is a perfect environment for this type of data-centric system modeling.

Figure 10
Revit Systems enables electrical system modeling within the context of the entire building model

System Modeling
With Revit Systems, electrical engineers model the power and lighting circuitry of the building spaces. During system modeling, the user places light fixtures, power devices and equipment in the model, then creates a circuit connected to a distribution panel. The user defines wire types, voltage ranges, distribution systems, and demand factors to ensure the compatibility of electrical connections in the design and prevent overloads and mismatched voltages.

The resultant circuit model allows users to calculate the estimated demand loads on feeders and panels, and then use these loads to adequately size equipment in the design environment. Load balancing is made easy when managing circuits; with the click of a button users can balance electrical loads between the buses on their panels. Built-in circuiting tools also allow users to total loads and generate reports for accurate documentation.

Figure 11
Revit Systems allows electrical engineers to model the power and lighting circuitry of the building spaces.

A System Browser lets a user check the continuity of an electrical model to identify orphaned elements that are not connected to any system, making sure that system elements are properly connected and contribute to system load requirements for optimized circuitry. Once the circuits are defined, Revit Systems automatically "wires" the electrical devices by placing annotation that includes the homerun to the panel assigned to the circuit.

Built-in electrical calculations enhance the system design with engineering data, providing design decision support from the building model and reducing the burden of manual calculations. For example, Revit Systems can automatically estimate lighting levels in rooms based on the lights placed in the space, excluding daylight. The user just defines the reflectivity values of the room surfaces, attaches industry-standard IES data files to lighting, defines the calculation workplane height and the system automatically calculates the average estimated illumination value for the room.

Figure 12
Revit Systems automatically places wire directly in the model as annotation during layout.

Figure 13
Revit Systems automatically calculates the average estimated illumination value for a room based on predefined electrical parameters. The calculated illumination values can be scheduled in a report for design documentation.

Increased Coordination
Coordination between a building's electrical and mechanical systems is critical, as one powers the other. The data-centric approach of Revit Systems provides engineers a holistic view of the building model and systems. For examples, a user can review the electrical requirements on mechanical equipment, and configure voltage and power load requirements to dynamically update in panel schedules.

In addition to building model and system coordination, a purpose-built BIM solution like Revit Systems automatically coordinates all design documentation as well. Like all Revit platform solutions, drawings, sheets, views, schedules, reports and so forth are all "live" views of the same underlying database. Therefore electrical documentation such as electrical plans and panel schedules are always consistent.

Figure 14
Revit Systems automatically creates panel schedules, such as the one shown opposite, and automatically coordinates all design documentation such as this.
Enhanced Communication
As described earlier in the building mechanical design section, Revit Systems includes a variety of features that enhance project communication: distributed building information modeling via Revit Worksharing, import/export features, visual communication techniques, etc. This is equally important for electrical designers and all the same Revit Systems features apply. For example, electrical designers can export their Revit Systems model to Autodesk VIZ to produce photorealistic lighting renderings or upload their files to an Autodesk Buzzsaw site or export their design to a CAD format to share with a client.

Figure 15
Electrical designers can use building information modeling to study lighting levels and design directly in Revit Systems, or export to Autodesk VIZ for realistic lighting visualizations such as the image shown here.

Inside a Revit-based Design Team Workflow
Since Revit Systems is built on the Revit platform, coordination between MEP team members using Revit Systems, architects using Revit Building, and structural engineers using Revit Structure is streamlined.

The architectural spaces created using Revit Building can be used by Revit Systems to support load calculations, track airflow in rooms and coordinate panel schedules. The architectural and structural elements created by (respectively) Revit Building and Revit Structure can be used to uncover potential conflicts with MEP system components early in the design process.

Well-established processes for worksharing amongst Revit users equally apply to MEP engineers using Revit Systems. Revit Worksharing distributes the power of the parametric modeling environment across a project team, providing a complete range of collaboration modes to suit the workflow and requirements of the parties involved, including the following alternatives:

1. On-the-fly, simultaneous access to a shared model between architects, structural engineers and MEP engineers.
2. The formal division of the project into discrete shared worksets that are reserved for editing by a single user at a time (such as "floor_1_architectural", "floor_1_structural", "floor_1_mechanical", "floor_1_plumbing" and so on).
3. A complete separation of project elements or systems into individually managed but linked building information models.
   

File linking works like the External Reference (xref) capability in AutoCAD software, with the added capability to monitor and update specific key elements that are shared in the design process. Worksharing offers the additional ability to propagate and coordinate changes between designers, documentation and disciplines.

A user works independently in a workset, periodically posting changes back into the master project file and refreshing the workset with changes from other users. Worksets can be displayed as needed, avoiding the memory-intensive display of parts of the building model that aren't necessary for a specific design activity. For example, an electrical engineer may want to constantly view the architectural workset, but toggle the visibility of the structural workset on or off to suit his design needs. Standard modelviewing mechanisms are supported for worksets, allowing the MEP engineer to create drawings that include any elements from the shared models.

Figure 16
Revit Worksharing streamlines coordination between MEP team members using Revit Systems, architects using Revit Building, and structural engineers using Revit Structure.

Summary
Autodesk Revit Systems offers MEP engineers advanced functionality for building electrical and mechanical design. The computable Revit building model allows firms to create, manage and share design information more effectively - contributing to increased profitability, reduced risk and fewer inefficiencies in building design. Parametric change management helps eliminate coordination errors in documentation sets, and minimizes coordination errors between engineering design teams - as well as architects and structural engineers within Revit-based workflows.

Firms can finally transition from a workflow based on 2D drafting to the holistic approach of integrating whole systems in a 3D digital environment, facilitating digital information sharing for engineering analysis and digitally-driven design for buildings.

Consider these comments by Bob Gracilieri, President and CEO of SEi Companies, a mechanical, electrical, plumbing, and fire protection firm known for working in sophisticated environments on complex projects. "BIM brings a new dimension to the way MEP firms can do business," reports Gracilieri. "It allows us to get out of the commodity mode and offer a value proposition service to our clients. It will change the whole culture and image of our industry."