Barriers to Building Information Modeling

Barriers to BIM
The ultimate objective is to build an integrated BIM—a virtual building before we make expensive mistakes with concrete, glass and steel. But tradition, contractual separation, archaic laws, technical limitations, interoperability problems and culture hinder us.

Software and hardware constraints: A BIM model theoretically has unlimited ability to hold information. But any practical project model will fall short of what is theoretically possible. Despite faster and faster computers and more efficient software, the model slows down as it enlarges.

Cost practicalities: At some point, it becomes impractical to add detail to the model. We still assume the builder will use some judgment in the field. A drawing doesn’t need to show all the nail locations in a wood frame.

Universal adaption: The fruition of BIM will depend on widespread use by designers, contractors and manufacturers. But until trade contractors and manufacturers are operational with BIM, we will limp along with incomplete integration.

Interoperability: Any CM or PM that has managed a program that included multiple architects and multiple CMs has faced the frustrating problems of interoperability in trying to integrate data from different project management information systems. It is hard to share data between Autodesk’s Constructware, e-Builder and Meridian’s Prolog. The same problem exists with BIM software.
A fully integrated BIM model is a vision, not a reality. At current levels of development, architects engineers, consultants, builders and fabricators may have independent BIM models, legacy CAD systems and legacy paper systems. Those who use BIM software may not use the same programs

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BIM Model Management

Managing a BIM Model

Managing a Building Information Model is similar to managing an actual model in site.  A construction manager must understand the technology of construction. But the more crucial job is orchestrating the work of hundreds of organizations—coordinating the assembly of materials on-site with decision-making, sequencing, and supply chain management.

Most of a project is built off-site. If the on-site management team doesn’t manage the off-site activities there will be delays. Managing the interrelationships is as important as understanding the technology of the work. In the simplest sense, it doesn’t do any good for a construction superintendent to know about forming and finishing concrete if the concrete truck isn’t scheduled for delivery at the right time.

A BIM model has similar requirements. Managing the development of a virtual construction model requires skills that are similar to managing the real thing. Too often BIM production is staffed with people who understand BIM technology but don’t understand how to manage the workflow from multiple sources.

The management job requires setting BIM standards, understanding constructibility and construction sequence, evaluating supply chain data and vetting information that is submitted to be input into the model. But most of all, it requires understanding how to suck this information from multiple sources into an integrated model. The manager must have clout in the organization to get the attention of the extended IPD team to schedule information flow, analysis and problem solving. And since inputs to a BIM model may ricochet through the model, the manager must review and evaluate the accuracy of inputs—just as a CFO ensures that there are procedures to evaluate the inputs of financial information before they are posted to a general ledger.

A BIM model manager requires the support of the IPD management committee who must set policies to adopt the technology, buy and install the software for members who do not have it, train the team, champion the use. Finally, they will need to establish workflows for a BIM process that may be developed by the BIM model manager.

An IPD team needs a BIM manager and an interdisciplinary BIM team staffed with people from member firms. The BIM team integrates drawings from the AEs, subs and manufacturers. They develop 4D and 5D models. They detect coordination problems with clash detection routines. Constructibility reviews trigger design adjustments—made with the collaboration of the AEs. RFIs are anticipated and if collaboration ongoing, should be minimal. In developing the model, questions surface before construction.

The BIM model manager must be a person with good interpersonal skills to build the collaborative culture required to produce an integrated BIM model. The manager must build trust and networks of personal communication within the contracting team. As with real construction, the more personal contact and the more trust, the more collaboration. BIM allows trust to be built early, well before construction begins. There’s an opportunity to allocate model space to each subcontractor to give them confidence that the process will not only find clashes in their systems before they get to the field, but that the sub will have the ability to model the clearances and working space needed to install their work.

Architects have typically been the primary source of BIM models, fulfilling their traditional role in developing the drawings and specifications that document the product—the description of the design, the intended physical result.

CMs have usually taken the lead in providing project management information (PMIS) systems—gathering and integrating data from the extended project team. These systems have concentrated on process—tracking contractual matters such as cost, schedule and quality control; RFIs and change orders.

But now CMs are developing in-house BIM teams and are developing BIM models prior to construction.2

Eventually, it is likely that an IPD Core Team will build integrated groups to produce integrated documents. Clearly, managing virtual construction will require technical knowledge of both process and product. Virtual construction will require AEs with product expertise and CMs with process expertise. 

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BIM in Industry

BIM Characteristics

A BIM model is a digital description of a project. It may include information such as the physical configuration, programmatic requirements, functional characteristics, specifications, systems performance, supply chain threads, construction sequence, cost or any other information that might be useful.

Plug-ins:

 Specialized software may be “plugged in” with algorithms that can adjust related building systems if there is a design change. These “plug ins” can include programs for structural and mechanical design. For instance, if a room is enlarged, the size of the structural members can be automatically recalculated and resized. The model adjusts itself. If the building is rotated on the site, the heat gain and loss may be recalculated. Other plug-ins may focus on energy analysis, LEED certification, cost estimating or construction scheduling.

http://www.youtube.com/watch?v=uyHYq1lhsSE

Reports:

 BIM ideologues will quickly tell you that BIM is not drafting software. It is a database. Drawings are simply one form of report. Like any digital database, a BIM model can produce reports—subsets of information for special purposes. These reports can be in the form of 2D or 3D drawings or an infinite variety of custom alphanumeric reports. The IPD team can tailor reports for specific purposes instead of grappling with a large set of 30” x 40” construction drawings and a fat set of specifications that obscures required information.

For instance, architects can produce a report in 3D and in color, rendered for comprehension by non-technical people. They can deliver drawings for review by entitlement agencies (building permits, accessibility requirements, environmental concerns, aesthetic compatibility or whatever) that address the agency’s specific requirements. Assembly details can be produced on site for current construction challenges. Facility managers may access life-cycle, maintenance and replacement information.

4D and 5D models:

BIM can have sequence and construction duration information attached to drawing elements that represent the building systems (4D modeling). A computer program can animate construction progression. A user can input a date to observe current state of completion. The builder can analyze on-site material staging problems, develop phasing plans, improve the sequencing of trade contractors or analyze the cost of construction delays. Cost can also be attached to drawing elements that represent building systems (5D modeling) for estimating and value engineering. The estimate can progress in lockstep with design.

Clash Detection:

At the simplest level, pasting shop drawings into a CAD drawing quickly indicates a misalignment or a poor fit. Even in a 2D model, it is obvious if a window doesn’t fit between a pair of columns. However, problems are not always that obvious in 2D models. Conflicts are often caused when a building system designed by one consultant interferes with a system designed by another

consultant on separate drawings. For instance, if a lighting consultant locates recessed light fixtures on an architectural reflected ceiling plan without checking beam locations on structural drawings, the recessed can may poke into a beam. And we have all experienced a mechanical engineer plotting duct runs that pass through the structural engineers’ beams. BIM software provides sophisticated “clash detection” routines that indicate when two systems or products occupy the same space.

Direct fabrication control: 

Traditionally, fabricators develop shop drawings based on their interpretation of the plans and specifications. They are checked by the AE. Errors occur at each translation. By pasting shop drawings directly into the BIM model, errors and conflicts are more apt to be detected. Ultimately, a BIM model may include algorithms for CNC.

Facilities Management:

 An integrated BIM model is a good bit more valuable to facility managers than typical “as built” drawings. It may contain warranty data, spare parts lists and sources, useful life expectations and maintenance recommendations. It may contain original layouts as well as remodeling and renovation documentation. direct fabrication of building systems, such as ductwork, curtain wall, millwork. While there are still opportunities for error in these automated processes, they are reduced and often eliminated. Precision is increased and supply chain workflow is shortened.

BIM as a contract tool:

Although IPD may minimize the contractual silos between the members, it is unlikely that an IPD team will include 50 to 75 subcontractors. Contractual separation will remain for most of the design and construction team. Multiple customized reports from a BIM model will assume important roles as contractual tools. The tools will work both ways—clarifying agreements with both the owner and with subcontractors.

The initial agreement with the owner will likely be a written document, perhaps with some simple diagrams to describe the intended result. As the project progresses, printed reports from the BIM can then augment that original agreement, defining the work for staged approvals just as traditional SD, DD or CD documents have done. However, rendered 3D reports from the model will do a better job of ensuring a meeting of the minds with the owner or users who may lack experience with technical Construction Documents.

Computer Numerical Control refers to computer instructions that drive machine tools used to fabricate components. The technology is labor efficient, accurate, repeatable and facilitates complex forms.

The BIM will then become the framework for describing the work to subcontractors. As the design develops, subs will be asked to propose or bid on aspects of the work. When selected, aspects of their technical proposal may become part of the BIM—to be augmented or replaced with shop drawings as their work is developed.

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BIM Evolution

Evolution of BIM

Courtesy: YouTube

EVOLUTION
Vector CAD: 

The first generations of CAD represented buildings with geometry—vector based lines, arcs and circles. A CAD drawing was easy to modify and replicate. It also provided greater precision than pencil on paper. But it was dumb: lines drawn with a computer instead of a pencil.

Object CAD: Then “smart” objects with properties were added. Objects like windows, doors, walls, roofs or stairs had properties that governed their behavior. A window could be pulled from a resource file into a drawing and stretched to fit the required opening. As it was stretched, the panes would grow but the jamb section would not. A user could associate information to the object such as the supplier, part numbers, the finish, the warranty and so on. The drawing objects were “smart.” They knew how to behave and what they were.

BIM: From that point, it was a logical step to envision an entire building as a smart object with endless possibilities for algorithms that govern its behavior and and associated information. BIM emerged.

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Revit 2014---Estimation and Costing

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Revit 2014---Material Takeoff

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Revit-Navisworks: Clash Detection

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