Geo Week News

May 31, 2011

Is data capture getting lost in BIM discussion?

There’s little doubt that BIM is the hottest topic in the AEC community nowadays. You see those three letters everywhere. However, if the 3D data capture industry is to take advantage of this embracing of 3D design, it needs to act quickly to raise its hand. Conversations are being held all over the world about BIM best practices, interoperability, and the codifying of what is still a relatively new process, and it appears that 3D data capture professionals are being often left out of those discussions. 

Take the recently announced Institute for Building Information Modeling in Canada (the IBC, for short). Its web site went live earlier this month, and it has admirable goals: “Its founding partner organizations represent specific industry sectors that have a keen interest in seeing BIM implemented in a way, and at a pace, that enables the primary stakeholders to understand their roles and responsibilities and to assess their capacity to participate in this process. IBC’s priorities include an awareness program, a practice manual, a bibliography of useful resources, and a full environmental scan/assessment on the use of BIM in Canada and internationally.”

And that scan/assessment has already been released. You can download it here. In many ways, it’s not a bad document. If defines terms, talks about issues standing in the way of widescale adoption, etc. But there’s a fundamental problem with the document, too:

It contains exactly zero information about 3D data capture. The word laser does not appear in the document. In the list of 79 “tools” being used in BIM, not one involves 3D data capture. The tools are software only, and there is a fundamental disconnect between this software and the actual real-world: How does one check to see whether what is being designed is what is being built?

And the document actually does talk about this aspect of BIM’s use. To whit, its discussion of BIM’s use in “site modeling”:

The 3D model of a site, including its geographical information, is used to determine the most suitable location for a facility. It is used to compare different sites, as well as to choose the position of the building on the site, based on specific financial and environmental factors. BIM plays an important role in representing and visualizing existing site conditions captured as contoured models or “toposurface” which form the basis for construction activity scheduling. The site plan drawings are derived from the site models which contain placement and orientation details, reference geo-spatial datum, which are required for specific construction activities, such as drainage, roadways etc. Additionally, these models may contain labor resources, materials and associated deliveries. This provides a base for the owners, architects and engineers to determine the optimal site location based on criteria such as solar and light availability, access, etc. 

Well, hey, how do you suppose you build that 3D model? Just going to eyeball it, are you? Someone needs to get a mention of laser scanning in here. Isn’t a point cloud of the site going to be pretty useful as you go to build an accurate model of the location for your new building? I’m thinking it would be, but you’d never know it from this document. 

Here’s another example, from a section discussing the use of BIM in the construction phase:

This 4D BIM can be used to show a time-based animation of the addition of the different components of the building as they are expected to occur at the construction site, providing a powerful illustrative capability. This can help the team to better understand the construction activities and milestones, as well as to detect and avoid spatial and temporal conflicts during actual construction. It provides an integrated view of how humans, equipment, and materials will come together at the site. It can also be used to easily communicate the complexity and the progress of a project. 4D BIM provides construction project visualization, scheduling, phasing and transparent project management. This helps the project team to better understand the zones, spaces and related construction schedules. Currently, 4D BIM is commonly found as an on-site production control tool. 

How are you to know if you’re meeting scheduled build deadlines? The contractor just eyeballs it and gives an estimate of completion percentage? And the asset owner is just going to take his word for it? What if they disagree? Laser scanning or photogrammetry here could document precisely how complete a building is at a period in time, documenting exactly the progress that is being made, and creating a record that’s indisputable. Further, if you’re talking about on-site production control, what better way is there to make sure a building is being built as designed? Especially with buildings that involve more non-standard shapes, laser scanning is the perfect tool for making sure the curvature is correct, the height is right, the distances are accurate, etc., as progress is being made in construction. 

Someone needs to give the IBC a heads up about this. 

And let’s not even get started talking about how this document basically ignores the use of BIM for the retrofit and modification environment. How do you get that 3D data set for an as-built condition that needs to be designed around? Scanning and photogrammetry could be awful helpful there, I can assure you. 

Why is this important? If AEC firms are reading a document like this, and are unfamiliar with 3D data capture’s potential for BIM sue, they can quickly learn of technological advancements and that can lead to growth in the industry, sure. But there’s a bigger, philosophical point here, too. 

BIM will only work if it has a tangible relationship to reality. If we’re going to use BIM to make predictions about energy use, and building performance, etc., we have to make sure that the BIM is rooted in reality, and the best way to capture reality and make it digital is through laser scanning and integrating a point cloud or other real GIS information into the work flow. 

If everything is just going to live inside a computer, and we’re just going to hope that what exists in reality is accurately reflected by the software because, well, it seems to look right, that’s going to limit the effectiveness of the BIM. No question about it.

Frankly, I’m blown away that an “environmental scan” of how BIM is being used right now has absolutely no mention of 3D data capture or even the term “scan-to-BIM.” Blown away. 

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