U.S. General Services Administration
BIM Tutorials: Revit Model Sharing
As part of your BIM deliverables, you are required to provide a unified dataset, but how can you do this if multiple BIM exist of the same building or parts of buildings? How will you reconcile your design and construction models at the end of the project?
One option is to have one unified Master Model instead of a design and construction model.
The Challenge
Traditional 2D Revisions
For years a disconnect has existed between design and construction documents. This disconnect occurs as soon as the project fabricators become involved with the project.
Often a project team will hand over a copy of their 2D and 3D data to the fabricators as soon as the fabricators become involved in the project. The fabricators will begin developing fabrication level data from that original dataset. From this moment on, you have a fractured model environment.
In a simple 2D world this fractured environment, although very inefficient, can be managed. The design team would continually issue addendums, revisions and bulletins, which the fabricators would reference to adjust their drawings. Besides being very costly and inefficient, this process is prone to errors and almost always leaves the owner with two disconnected sets of data at the end of a project.
In today's BIM-based world, GSA is no longer willing to accept this fractured dataset as a final deliverable. When a building owner has multiple sets of conflicting data, it is nearly impossible to leverage the data for facility automation and management.
Workflow
Sharing the project dataset is one recommended workflow to achieve a unified model. Although not required, sharing the project dataset is the only path to minimal waste in the development of the required unified deliverable at project completion. You can be accomplish this in several ways, your team will need to develop strategies that best suit your needs.
Traditional Workflow for Project Data
In the traditional workflow, project data becomes fractured once the construction team enters the project. For many years this has been unavoidable, but tools now exist to minimize or eliminate this waste.
Optimal Workflow for Project Data
With an optimal workflow for project data, all team members contribute to a single unified dataset. This single dataset evolves over the course of the project with each participant contributing their specific knowledge to the project.
For example, the mechanical designer may place a VAV box in the model and complete several of the COBie2 entries related to the requirements of the unit. As the project progresses, the mechanical installer will add installation-specific data to the exact same model object.
The Options
As the data creators, your team must decide which strategy meets the project's goals and required deliverables. The simplest but most costly option is to maintain the legacy practice of model fracturing and then manually reconcile all the data to a single BIM at the end of the project.
In many cases this may require the data creator to completely remodel the data. For example, if the sheet metal fabricator worked in FabMEP, you can't import that data into a format that meets GSA BIM Guidelines for Revit. You will have to remodel the data in a format that supports the ability to add the attributes and grouping required by the Standard.
Until recently the only option available was the fractured workflow. However, new advancements in BIM tools have opened up cost savings opportunities for BIM data creators. The options listed below will focus on tools available for the Autodesk Revit platform, but many solutions now exist for most BIM authoring tools.
WAN based Sharing
The most popular way to share project data is the extension of a company Wide Area Network, or WAN, allowing partners to directly access shared project data. In the Revit environment this shared WAN is typically supported by the use of network accelerators, the most common of which is Riverbed Appliance. When properly deployed on a very low-latency/high-bandwidth network, a distributed WAN can allow multiple parties to access a single Revit model.
Autodesk Revit Server
From Autodesk:
Revit Server is the server application for Revit Architecture, Revit Structure, and Revit MEP. It is the foundation for server-based worksharing for Revit projects. A workshared project is a Revit building model that multiple team members can access and modify at the same time. With server-based worksharing, multiple instances of Revit Servers are installed at different sites and configured to perform specific roles to support optimal project collaboration across a wide area network (WAN). Together these instances of Revit Server make up the Revit Server network.