How Buildings Are Like Hair on Virtual Monsters

We recently read a CAD Digest article about a skyscraper project in Seoul, South Korea that used an innovative approach to computational modeling of building elements. The project, called the Lotte Super Tower, used a concept called "digital data models" which creates a mathematical or programmatic design of a building before any geometry is created.

When we read the article, we immediately thought back to a similar problem that isn't in the architecture, engineering, and construction (AEC) industry: hair on virtual monsters. We'd like to compare how a skyscraper can be like the hair on Sully, the purple-spotted, ape-like protagonist of Monsters, Inc. 

          

Sully getting animated. (Source: The Verge)

First, let's talk about how the Lotte Super Tower used digital data models. The building is a 123-story project where the curtain wall façade twisted in complicated ways along the vertical axis of the building. Because of this geometry, every floor had a unique exterior wall system layout, interior wall elements, and floor plan.

Architects at SOM created a digital data model of the BIM model and defined the network of key nodes that determined the layout of all the unique elements. Then, using scripting, the team automatically generated the desired unique modeling required for each floor. By automating the modeling process, the team removed the potential for manual drawing errors, reduced the overall modeling effort, and made a highly technical problem into a manageable digital workflow.

How is this related to digital ape monsters? Sully is covered in blue hair. Each hair moves when Sully moves, has a particular poly-line shape, has a unique length, and reflects light based on its position. Computationally, it is an exceedingly difficult task to model each hair over the many millions of frames needed for a feature-length animated film. So what did the Pixar team do? They created a digital design model.

Rather than model each hair, they created a node point – a hair follicle – that had parameters like color, length, location, and orientation. Based on these nodes, the hair was then automatically modeled for each frame of the movie. When Monsters, Inc. was produced by Pixar, this was groundbreaking work. No prior animated film featured so many individual virtual hairs. This work has now been copied in many other films that feature hairy animals.

What can we learn from Monsters, Inc. and the Pixar team? Digital data models aren't unique to the AEC industry; other industries have extended them to perform very complex computational tasks. AEC will continue to apply these strategies to the built environment, but we hope that we don't follow the animation industry too close – we don't think we need entire buildings covered in blue and purple hair.

 

Tags: BIM AEC CAD

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