1-2-3 REVIT: BIM for Interior Design Information13 Feb, 2006 By: AIA ,Rick Rundell Cadalyst
Building information is fundamental to the interior design process.
In previous articles, I explored how interior designers are applying BIM (building information modeling) -- enabling designers to model and visualize the inside of a building, and to capture and manage that design thinking as multiple options within a single building model.
This month, let's examine how interior designers can take advantage of the data stored and managed within the building model. The data embodied by BIM is fundamental for tasks throughout the interior design process: early design activities such as schematic space planning and master scheduling; the accuracy of detailed design activities like quantification and costing; and finally for the production of well-coordinated documentation.
BIM systems allow users to add non-graphic properties such as product name, finishes, cost, etc., to building components. Some object CAD systems store non-graphical data about a building in a logical structure with the 3D building graphics. Users extract this data to provide information about quantities and attributes, just as they extract the 2D drawings from the 3D graphics. But additional tools and effort are required to keep the graphical and non-graphical data synchronized. The larger the project, the greater the effort required to keep the data coordinated and the greater the risk of inconsistencies.
Software specifically designed for BIM, such as Autodesk Revit Building, combines a design model (3D building geometry and non-graphic properties) with a behavioral model (change management) into an integrated parametric building model. The entire model (including the design documents) is in an integrated database, where everything is coordinated and internally consistent.
Some non-graphic interior design information is visible in project drawings -- a room number or name on a plan drawing for instance. Other information may ultimately only appear in schedules -- the door hardware set in a door schedule for instance. But regardless of where the information is ultimately displayed, the single source is the BIM. Revit Building stores and manages all the interior design information and coordinates the information across all representations of the project (figure 1).
Figure 1. Autodesk Revit Building uses live views of drawings and schedules of building components, so they are always accurate.
Prior to detailed design, firms can create a master schedule for interior spaces -- a working database view of a project -- that includes a large amount of non-graphic data regarding areas and room types. In this fashion, Revit Building users can employ table-based schedules as the input medium for many interior design components.
Clayton Starr, senior applications administrator for RTKL http://www.rtkl.com, explains how their interior design group used this master schedule approach to pre-define spaces for a recent hospital project. Their designers loaded up the Revit BIM with a host of non-graphic information such as room type (examination, patient, surgical, etc.), area requirements, furniture and equipment requirements, planned finishes and materials -- down to the type of material used for a window sill. "By adding this level of detail so early in the design, we can produce remarkably accurate preliminary estimates," Starr said.
As design progresses and actual spaces are modeled, Revit Building allows designers to check their design model against their design requirements. For instance, a designer can automatically calculate a room area and compared it to an area requirement schedule to flag rooms that are too small (figures 2 and 3).
The ability of Revit Building to store, manage and coordinate design information is essential for the precise tracking and reliable quantification of building materials, supplies and equipment. Other design technologies scatter building information across multiple CAD files or require user intervention to make sure that all of the building information is internally consistent -- resulting in less reliable information retrieval. In contrast, schedules and quantities of building components in Revit Building are live views of the building database, and therefore always accurate.
Revit Building allows users to calculate area and quantify materials effortlessly and reliably -- reducing overall project cost by producing accurate estimates and eliminating the ordering of excess or unnecessary materials. Accurate area measurements lead to accurate finish budgeting for items such as carpet, wall coverings, ceiling tile or finishes. Accurate furniture and equipment counts leads to accurate schedules for those items.
Returning to the example of RTKL's hospital project, hospital spaces contain very specialized, very expensive equipment that require long lead times for ordering. By involving the interior design group early in the overall project (during the start of detailed design in this case) and relating detailed equipment schedules to emerging design spaces, RTKL produced a better overall design with minimal late changes and precise equipment counts (figure 4).
Figure 4. RTKL used Revit Building to relate detailed equipment schedules to emerging design spaces, such as this hospital patient room.
The accuracy and level of detail of the Revit BIM can also segue into more effective ways of managing and operating the resulting facility. The ability to track occupancy, space allocation and assets is prompting some firms to contemplate how to leverage the BIM for future service offerings.
With Revit Building, all the construction documents relating to the interior design are direct presentations of the underlying building model -- including schedules, material take-offs and other informational views of the building. Revit's parametric building modeler coordinates all changes to the interior building model. If an interior wall is deleted, the lighting sconce on that wall is deleted and all related documentation is updated as well. The plan and elevations drawings that contained the wall and sconce, the electrical plans that contained the sconce and the related schedule of lighting fixtures -- all are instantly updated.
Revit Building offers interior designers a single source for building information, a design environment without duplication of effort or replication of model information. The Revit parametric building modeler coordinates this information across all representations of the project -- giving designers, and their clients, confidence in the accuracy and reliability of their interior design documentation and information.
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