Multi-Discipline Project Coordination with Autodesk Revit Jim Stoneberger Avatech Solutions Neal O Neill Avatech Solutions
Origins Internal Origin, (0,0,0 in Revit) Revit does have an internal Origin point similar to that of AutoCAD or any other CAD program. This might not seem as apparent in Revit as it is in another CAD program because Revit does not use the same means of a Cartesian coordinate system when modeling walls or drafting line work. However, this Origin Point is extremely important when importing and exporting files for coordination with other disciplines. The Origin point in Revit is a fixed location and cannot be adjusted or removed. This is the point that is referenced when using the Auto Origin to Origin option for Linking Revit models or CAD files into a Revit project. Shared Coordinates Shared Coordinates are a secondary set of coordinates in a Revit project. The Shared Coordinate 0,0,0 point is a way of locating objects. The Shared Coordinate point is defined by the user by either Manually selecting a point in the project, or by Acquiring the coordinate from a CAD file or Revit file that is linked into the host project. Manually defining the Shared Coordinate by selecting a point. Note: When this command is selected, the user must then select a point in the project. The option will then be given to define what coordinate that point will be (east/west, north/south, and elevation). In addition the angle between Project North and True North can be defined. 2
Acquiring Coordinates from a Linked CAD file or Revit Model Shared coordinates can also be defined by acquiring the location of the 0,0,0 point from the CAD file or Revit project that is linked into the host project. If the linked file is brought in via Origin to Origin, then the 0,0,0 coordinate in the linked file will align with the 0,0,0 coordinate in the host model. Acquiring the coordinates from the linked file in this scenario would not change the location of the shared coordinate. Often times the linked file will need to be adjusted east/west, north/south, and/or vertically in elevation in order to align with the project in the host model. Once the linked file has been adjusted, the location of the 0,0,0 coordinate in the linked file is moved away from the Origin point in the host model. But the objects in the file now align correctly according to the design. When the file is moved, the 0,0,0 point of the linked file is moved, hence moving the origin of the linked file away from the origin of the host model. The user then selects Acquire Coordinates, and selects the linked model for which the coordinates will be acquired from. This will set the 0,0,0 location of the Shared Coordinates in the host file to match the 0,0,0 location of the linked file. This will also rotate the orientation of the shared coordinate s North angle, or True North. True North is defined by the north orientation that is set in the Shared Coordinates. 3
Project Base Point and Survey Point While the internal origin point of a Revit project cannot be adjusted, there are two points in Revit that can Be. These are known as the Project Base Point and the Survey point. These points are visible in any view by turning them on in the Visibility/Graphics Overrides dialogue. They are both sub-categories of Site. By default, they are both set to non-visible in any view other than the Site Plan view. Also by default, they are located at the Internal Origin point in the Revit Project. 4
Survey Point When shared coordinates are established, the Survey point is moved to the Shared Coordinate 0,0,0 location. It is recommended that once the survey point is set, it is pinned in order to ensure that it is not moved. When selected, the Survey point will display its coordinates from the Shared Coordinate 0,0,0 location. Moving the Survey Point: The Survey point can be moved in two different settings; Clipped or Un-Clipped. When leaving the Survey Point clipped, moving it will result in changing the location of the Shared Coordinate 0,0,0. When Un-Clipping and moving the Survey Point, the Shared Coordinate 0,0,0 location will remain, but the Survey Point will be adjusted. Survey Point shown as being moved when unclipped. The N/S, E/W values are adjusted based on the distance from which the Survey Point was moved from the Shared Coordinate. 5
Project Base Point The Project Base establishes the location of the project coordinates. This is the point that will establish the location of elements modeled in a project in relation to other elements. For example, the Point might be moved to a specified corner of the building. Anytime that another point is referenced using Project as it s coordinate basis, it will reference an E/W, N/S, and Elevation value from the project base point. When selected the Project Base Point will display the coordinate values based on its location in relation to the Shared Coordinate 0,0,0 point. Moving the Project Base Point Similar to moving the Survey Point, the project base point can either be clipped or un-clipped. When clipped, moving the Project Base Point is the same thing as using the Relocate Project tool. DO NOT BE FOOLED, you are not actually moving the project base point or internal origin. You are simply changing the location of the Shared Coordinate 0,0,0 point. If the Project Base Point is un-clipped, its orientation to the Shared Coordinate changes. It is in fact moved from the project internal origin. If desired, the project base point can be moved to its original location (or the project internal origin point). To do this, the Project Base Point must be un-clipped. Select the Project Base Point, Right Click and select Move to Startup Location. 6
CAD Files Importing and Linking CAD Files CAD files, such as.dwg,.dxf,.sat, etc, can be imported or linked into a Revit project. There are many uses for importing CAD files. Among them are using the topography that is drawn in a civil file to model a toposurface, or coordinate the location of duct work and piping in relation to the objects modeled in Revit. Both 2D and 3D CAD files can be imported or linked. Importing vs. Linking When importing vs. linking CAD files, there isn t a difference in what information is brought into the project. The difference is how the information is to managed. Importing a CAD file simply brings that CAD file into the project. A relationship is NOT maintained between the CAD file that is in the Revit Project and the original from which it was imported. Linking a CAD does maintain a relationship with the original file that it was created from. Similar to an XREF in AutoCAD. Origins of CAD Information CAD files follow the same rules discussed previously. When a CAD file is Linked or Imported into Revit, it is a Best practice to try and use Origin to Origin. However, there are times when Origin to Origin does not work. When a file is linked into Revit, the information in that file must be within a one mile radius from the origin point. If anything is drawn or modeled outside of that one mile radius, Revit will revert to Center to Center.This isn t any different from moving the information after it has been placed. Once the file has been properly positioned, shared coordinates can then be set by acquiring coordinates from the CAD file (as described previously). It is also possible to Publish Coordinates to a CAD file. Doing this will create a Named UCS in the AutoCAD file. Exporting a CAD File Often times a consultant is not working in Revit and needs 2D or 3D CAD files as backgrounds for their work. Revit information can be exported to a CAD file through the Export option located in the Application Menu. 7
It is important to first understand whether the consultant needs 2D or 3D CAD information or whether or not they need just Model views or Sheets with Model views. Either Model views or sheet views can be exported. When exorpting Model Views, the 3D view will export a 3D model. The user has the option of exporting as a polymesh or as ACIS solids. 2D views will export as 2 dimensional flat line work. If AutoCAD, These objects will be placed in the Model Space of the CAD file. When sheet views are exported, the sheet titleblock and all information placed on the sheet view will be placed in the Paperspace of the CAD files. Viewports will be created based on the boundaries of the viewports in Revit. The objects in the views will be placed in Model space and viewed through the viewports created in the same orientation as defined in Revit. If desired, the objects in the viewports can be placed in individual files that are XREFed into the Model Space of each file. Object categories will be converted to layers based on the Export Layers.TXT file that is chosen. 8
Establishing the 0,0,0 location in the CAD file The 0,0,0 point of the CAD file can be defined when exporting from Revit. The default is for the 0,0,0 point to match the Internal Origin of the Revit project. Typically this is not the desired location of the 0,0,0 point. If a consultant moves the floor plan information or 3D model in the CAD file, linking this CAD file back into Revit using Origin to Origin will not allow for the geometry of the objects to align. The methods discussed previously must be used to realign the information. It is important to communicate and agree with the consultants working in CAD or Revit what the guidelines will be when sharing information. For Example, the Architect might agree to establish a reasonable 0,0,0 point, in turn the consultant would agree to not move the information once received Defining Additional Shared Coordinate Locations One way for controlling this information is to establish a common point that will be used as the shared base point. This is a point that will be the 0,0,0 point of the CAD files and one of the Shared coordinate points in Revit. It is possible to have more than one Shared Coordinate point. This is established by defining multiple locations within the Revit project. From the Manage tab, select the Location command. The default location is titled Internal. 9
If the coordinates have been acquired from a CAD or Revit file, or if the Shared Coordinates have been established, the information for those shared coordinates will be kept in this Internal location. In the Manage Place and Location dialogue additional locations can be set up. The suggested method is to rename Internal to something descriptive that refers to the Acquired Coordinates, such as Site Location. An additional shared location can be created by selecting Duplicate. The Name of the new location might be something like Export 0,0 Location The new location can then be selected and made the current location. Once a new location has been created, the Survey Point (or Shared Coordinate) can be adjusted. The Survey Point is moved to the location of the desired 0,0 point in the CAD file. When Exporting the to a CAD file, the option for the Coordinate System Basis can be set to either Project Internal, in which the 0,0,0 coordinate will be based on the Internal Origin, or Shared. When set to Shared, Revit will use the Shared Coordinate point of the current location. The 0,0,0 coordinate in the CAD file is based on the location established for the additional Shared Coordinate that was defined. 10
Linking Revit Models Type Parameters of a Linked Revit Model Room Bounding When this parameter is set to Yes (by checking the box in the value column), the elements in the linked model that are set to be room bounding (such as walls, floors, ceilings, etc ) can be used as room bounding elements in the host model. This is an important parameter to set when the linked model is to be used to define rooms or spaces in the host project. Reference Type The Reverence Type Determines whether this linked model will be displayed (Attachment) or hidden (Overlay) when the host model is linked into another model. When a model that contains linked models is linked into a Revit project, the nested links of that linked model display based on the value that is assigned to the Reference Type parameter. Phase Mapping When a Revit model is linked to another that has more than one phase, the phases in the host model automatically map to phases in the linked model. The default is for Revit to map phases based on the name of the phase. Phase mapping can be adjusted. Phase maps must occur in chronological order. 11
Visibility for Linked Revit Models Parameters that control the visibility and appearance of linked Revit models are grouped under their own tab, Revit Links, in the Visibility/Graphics dialog. The Revit Links tab in the Visibility/Graphics dialog contains the following: Visibility column: Select the check box to show the linked model in the view, or deselect the check box to hide the linked model. Halftone column: Select the check box to display the elements from the linked model as halftone. Display Settings column: View options to override additional settings for each linked model. The button displays the current display setting state (By Host View, By Linked View, or Custom). A view template can be used to save the visibility settings of a particular view and then apply it to other views. By Host View. When this option is selected, the graphics of this link cannot be overridden. The host view governs its appearance. By Linked View. When this option is selected, a project view from the linked model can be selected to be displayed in the current view. The views available to be displayed will be determined based on the type of view that you are adjusting the display settings for. Custom. When you select this option, you can select override settings on all available tabs. 12
Coordination Copy/Monitor There are five categories of elements that can be copied and/or monitored between Revit projects. Grids, levels, columns, walls, and floors. Within the Walls option the user has the ability to also create openings where Doors and windows are located. Copied elements are automatically monitored against the original elements. The monitoring functionality sets and maintains relationships between objects of the same category. Note: openings that are in the host or linked project can be monitored against Doors and Windows. To begin the Copy/Monitor process, select Cop/Monitor from the Collaborate tab. Once in the Copy/Monitor function, options can be set for the objects that are to be copied. The Copy/Monitor Options dialog opens. Each tab contains various options for that type of element. The column on the left displays the type from each category that will be copied from the linked model. the Column on the right displays what element type each instance will be placed as. 13
Example: The column on the left displays the original wall type as Exterior Brick on Mtl. Stud. When this wall type is selected to be copied and monitored, it will be pasted into the current project as Generic 6. 14
Coordination Review of Element Relationships When elements that are being Monitored are modified, a warning is displayed telling the user that a Coordination Review is required. the Coordination Review tool will display the differences between the elements that are being monitored. Warnings can occur when one of the following takes place: An original monitored element from the linked project has changed. A Copied/Monitored element in the host project has changed. Both the original monitored element and the copied element have changed. The original element in the linked file was deleted. The copied element in the host file was deleted. To review warnings about project changes, select the Coordination Review drop-down under the Collaborate tab. Select Link to check warnings between the linked and the host projects. The options that are available when an element has changed are Do Nothing, Reject, Accept Difference, or to make the same adjustment. Interference Checking The Interference Check tool detects where object intersect one another in a project. interferences can be from a set of selected elements or all elements in the model. Interferences can also be detected between objects in a model and object from a linked model (such as structural elements checked against mechanical ductwork Note: Elements from a linked model cannot be checked against elements from another linked model. 15
Selecting Objects by ID Elements in the current project can be selected by using the ID number assigned by Revit. This can be helpful when trying to locate objects from an interference check as well as items that are listed in errors and warnings in Revit. To select an element by ID number, select the Element ID drop-down from the Modify tab. Revit locates the element and selects it in the view. The Show button can also be selected to toggle through different views until the item is found. 16