Building Information Modeling For Dummies. Swaddle Paul

Site information

      The location of the site may be obvious, but it carries a huge amount of embedded information about the environmental conditions and quality of land. Geographic information systems (GIS) and BIM evolved independently, but they have a lot in common. You can find hundreds of examples where infrastructure contractors have successfully married the two to improve projects at a macro scale. You can use GIS to understand the effect of topography and your site conditions on a proposed development.

       Outline and performance specification

      Understanding the client’s requirements for the project is a fundamental part of the design process, and without a good brief you can’t begin modeling. Rather than thinking of the briefing and specification as two separate activities, use master specification tools to generate an outline specification as early in the project as possible and then use that record as a foundation for developing the full specification.

      Say that a wall in your project has specific performance requirements (fire resistance or acoustic reduction) but the design team or client can’t decide on construction type. Specification tools allow you to record the performance requirements as part of the building information model. You can then link a placeholder object (such as a generic blank wall) in the geometry with the relevant specification data. This is a great example of something you can’t model with 3D CAD alone.

       Planning code requirements

      You can now find examples of where you can embed into the information model local code requirements like proximity to neighboring buildings or trees, limits on the height of buildings, and sustainability factors such as regional public transport routes. Doing so instantly increases your understanding of the impact of planning codes on your development, speeds up the design process, and can even help you justify your development to planning officials. We demonstrate some exemplar tools in Chapter 19.

Using information in the model

      Reviewers of the model are detailed design and technical design teams and consultants, such as structural engineers and mechanical engineers working together with architects, lighting designers, landscape designers, and the wider supply chain. Consider that the whole project team could be involved by this stage. In the following sections, we help you see how reviewers of the model coordinate, collaborate, and use the data BIM provides to the project team.

      

Traditionally, people had their own set of information, and coordinating everything was difficult. In the long term, a future method called Level 3 BIM (or iBIM) will provide cloud-based environments for all members of the project team to access. In the meantime, people still have separate sets of data, but BIM ensures that they all speak the same digital language.

      Assembling these interoperable models together is called federation. You may hear the term federated BIM, which basically means that the various parties have combined their work (fabric, structure, lighting, mechanical services) into one model, making it easier to see where the problems and clashes are. However, the authorship of the models is clear, so no confusion exists about liability or design responsibility. The information also has to go through a number of approval gates, which refers to a regular process of coordinating multiple sources of data into one, clear package of information for pre-defined stages of the project. Refer to Chapter 8 for more discussion about federated BIM.

       Prescriptive specification

      As the project evolves, you can refine in greater detail some of the objects that were placeholders at early stages. You can begin to rationalize the design and specification to indicate as many properties of each object that you know; for example, the appearance, materials, and finishes of the items that you’d previously specified just in terms of their performance. This is moving from a descriptive- or performance-based specification into a prescriptive one.

       Manufacturer information

      After the client makes decisions about systems in the project in the information model, you can begin replacing generic and placeholder objects with real building product manufacturer data. Alongside proprietary BIM objects that reflect the change, design teams can coordinate the specification data to provide access to manufacturers’ properties like energy consumption and guidance such as operation or maintenance instructions.

       Energy analysis

      Another great benefit of information modeling is that you can clearly see the impact of design, orientation, and engineering decisions on the energy efficiency of the project. Consider that designers and consultants can run sophisticated simulations to demonstrate solar gain and shading, thermal mass calculations, and power consumption. Now combine that with what you know about the energy regulations in your area, including Leadership in Energy and Environmental Design (LEED) certification in the United States (www.usgbc.org/leed), Building Research Establishment Environmental Assessment Method (BREEAM) for assessment in the UK (www.breeam.org), SKA rating for fit-out projects in the UK (www.rics.org/uk/knowledge/ska-rating), or Green Star in Australia (www.gbca.org.au/green-star). Harness the power of BIM technology so that you can see easily how small changes can improve the assessment.

      

Whenever you’re adding information into the model, think about what you need to embed in the model and what you can just link. In BIM platforms, you can associate objects with nongraphical information. Sometimes providing linked information is more useful.

Exporting information from the model

      Receivers of the data are the end users, which means anyone who may want to export information into another format, print an image or PDF, interrogate the model in a BIM-viewer software program, or generate maintenance instructions, such as a client or contractor.

      

The quality of your output can only ever be as good as the information within the BIM. Especially in federated models, you’re often reliant on the quality and accuracy of others’ work. For BIM to really work, the entire project team has to trust the professional competence and integrity of all the other parties.

      In the same way that you can add information to the model in various forms (geometric or text-based), you can also generate a range of outputs.

      Here’s a list of potential scenarios:

      ✔ You need to view part of the BIM for an internal design review.

      ✔ You need to output all data at contractor-tendering stage.

      ✔ You need to export the BIM to a model-checking tool to look for errors and clashes.

      ✔ You need to generate PDF drawings for building code approval.

      ✔ You need to print a visualization for a promotional marketing campaign.

      ✔ You need to send a drawing of a detail to a contractor on-site. Increasingly, contractors are beginning to use federated and cloud-based BIM for construction, and we look closely at on-site use in Chapter 16.

      

Information export often follows a pre-defined series of agreed outputs called data drops. The project’s BIM protocol describes the required file formats and exchange schema, which depend on the purpose of the output. Don’t worry; this just means a clear plan already exists for how the right amount of data needs to export and communicate your information, at the right time.

      Maintaining Information in the Model

      You need to think about the project beyond the traditional end of a design phase and past