BIM - Building Information Modeling
Building Information Modeling or "BIM" is the process where all stakeholders work collaboratively to produce a virtual prototype; whether it is a building, a site, an infrastructure system or a city. It allows every aspect of a design’s performance to be simulated and assessed before it is built; it is not simply "3D drafting" or "3D animation".
All designer information is embedded in an intelligent model; from materials to wind forces to water pressure in plumbing systems; so the project team can understand the implications of their choices, give regard to constraints, and identify opportunities - long before construction starts. This brings greater precision to project feasibility, cost and schedules; and reduces risk for developers and investors.
Building Information Modeling (BIM) is an intelligent model–based design process that adds value across the entire lifecycle of building and infrastructure projects.
“A BIM is a digital representation of physical and functional characteristics of a building. As such it serves as a shared knowledge resource for information about a building forming a reliable basis for decisions during its life-cycle from inception onward.”- BuildingSMART
There are an established set of industry definitions used to identify the different maturity levels of BIM and the concepts of 4D, 5D and 6D are used to indicate the elements and benefits of increasingly complex BIM models.
3D BIM Model
Experiencing designs before they are real ensures better decisions are made and enables participation by a wider audience of stakeholders or decision makers. Using visualization in conjunction with BIM on a project engages more people sooner, leading to broader-reaching feedback and more predictable outcomes. When the entire team can coordinate their work and share design inputs, they can easily assess the impacts of design alternatives and hone in on the best options earlier, and in parallel. This collaborative approach enables designers to respect the requirements of the other design disciplines and avoid costly and time-consuming conflicts and design rework.
Often on large projects the owner will request physical mock-up models so they can visualize, better understand and make more informed decisions about the aesthetics and the functionality of part of the project. BIM enables virtual mock-ups to be made and tested for a fraction of the cost and enable deigners and contractors to work together to identify and resolve problems with the help of the model. Viewpoints and animations can be used as compelling vehicles for transmitting design intent and facilitating conceptual buy in.
Traditionally design drawings must be coordinated to assure that different building systems do not clash and can actually be constructed in the allowed space. Accordingly, using the traditional design process most clashes are identified when the contractor receives the design drawings and during the construction phase. With clashes being detected so late, delay is caused and decisions need to be made very quickly in order to provide a solution. BIM enables potential problems to be identified early in the design phase and resolved before construction begins.
The level of construction information in a BIM model means that prefabrication can be utilized with greater assurance that prefabricated components will fit once on-site. As a result, more construction work can be performed offsite, cost efficiently, in controlled factory conditions and then efficiently installed.
4D BIM Model (Time)
Construction Planning and Management
BIM models provide a means of verifying site logistics and construction operations including tools to visually depict the space utilization of the job site throughout a project's construction. The model can include temporary components such as cranes, traffic access routes for lorries, lifts, and other large items that can be incorporated into the model as part of the logistics plan. Simple programme simulation can show the owner what the building will look like as construction progresses. This provides a very useful and successful marketing tool for all those involved in a project. Contractors can also use project visualization to understand how the building will be constructed.
Project managers can create a 4D simulation of the planned construction process by linking elements in the composite model to a timeline of project tasks. By watching the programme visualization, project members will be able to make sound decisions based upon multiple sources of accurate real-time information. Within the BIM model a time lining planning tool can be used to show the critical path and visually show the dependency of some sequences on others.
5D BIM Model (Cost)
Quantity Take Off
BIM models can be used to generate accurate quantity takeoffs and assist in the creation of cost estimates throughout the lifecycle of a project. This enables the project team to see the cost effects of their design decisions and proposed changes during all phases of the project, and this feedback supports better design decision-making and can help curb excessive budget overruns due to project modifications.
To determine a project's construction cost and requirements, contractors traditionally perform material ‘take-offs’ manually, a process fraught with the potential for error. With BIM, the model includes information that allows a design contractor to accurately and rapidly generate an array of essential estimating information, such as materials quantities and costs, size and area estimates, and productivity projections. As changes are made, estimating information automatically adjusts, allowing greater contractor productivity.
6D BIM Model (BIM FM)
BIM FM/AIM/Facilities Management (Buidling Lifecycle Management)
Where a model is created by the designer and updated throughout the construction phase, it will have the capacity to become an ‘as built’ model record of the building, whilst informing the final AIM. (Asset Information Model) The model will be able to contain all of the specifications, operation and maintenance (O&M) manuals and warranty information, useful for future maintenance. This eliminates the problems that can currently be experienced if the O&M manual has been misplaced or is kept at a remote location. Sensors can feed back and record data relevant to the operation phase of a building, enabling BIM to be used to model and evaluate energy efficiency, monitor a building's life cycle costs and optimize its cost efficiency. It also enables the owner to evaluate the cost-effectiveness of any proposed upgrades.
Using BIM facilities managers can effectively explore, track, and manage information using the powerful parametric capabilities and data embedded in the BIM model to analyze space related data, track inventory and lifecycle data and perform cost needs analysis.