Is Design Too Important to Leave to CAD?

August 15, 2016 | Comments

The party that happens the first Thursday of most months at Autodesk’s Gallery in San Francisco includes a presentation. Topics are fun, meant to engage the public and usually — but not always — extoll Autodesk’s role in the technological splendor of our modern world. But the last Design Night, as these parties are called, turned serious. It was about architecture, more specifically “The Built Environment, Technology and the Role of Data.”

Yet, they came. A few less than normal. A hot August evening may be better suited for a walk along the Marina. But it was a party after all, and $25 for food and top shelf liquor does make for the best deal for an evening in the city – and one where you might actually learn something.

image001Figure 1 – Sejung Kat Park of SOM getting ready to revamp our idea of how buildings should be designed. You thought it was CAD but you need a Master Data Model.

This night, the theme is Mediterranean food. In amongst the falafel and shawarma, the 3D prints pretending to be art, the DJ and his loud music, was Sejung Kat Park, MIT educated senior digital design manager at Skidmore, Owings and Merrill.

SOM, Kat the Very Tall Building

SOM is one of the premier architectural firms in the world (11th overall, according to Architectural Record, 2015 revenue of $245 million) and known for its tall buildings, including the tallest in the world, the Bhurj Khalifa (Dubai, 2010), the Sears Tower (Chicago, 1974) and several towering structures in between. Headquartered in New York, SOM has offices all over the world, including San Francisco.

We are introduced to Kat, who will be telling us of a few of SOM’s projects she has been involved with. One of them was the Lotte Super Tower, the 555 meter “supertall” skyscraper in Seoul, South Korea, finished this year, it is the tallest building in South Korea and one of the tallest in the world.

image004Figure 2 – The Lotte Super Tower in Seoul, South Korea, a 123 story tall building, has a square base and a round top, a shape designed to reduce vortex shedding, alleviating the effect of wind speed, which increases with height.

The Lotte tower starts with a 70 meter square footprint but its top floor, 123 stories higher, is a 40 meter circle. According to tall building experts, the shape transition helps to reduce vortex shedding, an effect of airflow over an object that can cause oscillations. Slender buildings are more prone to wind effects, like vortex shedding, which tapered buildings can more easily resist.

image005Figure 3 – Vortex shedding downstream of a cylinder. Image from Wikipedia.

A Surprise: It’s Not All About CAD

If you were expecting yet another super tall building and how it was completed, from a napkin sketch, to rendered images of a CAD model, to pictures of ribbon cutting with a billionaire owner and the mayor of Seoul — that’s not happening.

image007Figure 4 – This is what a building looks like? Excel spreadsheet generated by a AutoLISP program gives the coordinates and sizes of glass panels and structural elements in the Lotte Super Tower.

Instead, we see screens of numbers on an immense Excel spreadsheet. We hear of equations, used with generative design. Kat shows programming code — in AutoLISP. People still use that? But the biggest surprise of all, that CAD tools, not even the state of the art 3D BIM tools, not even the ones bought to you by our kind host this evening, were sufficient, and that even worse, they imposed constraints that stifled creativity.

To make a really complicated building these days, says Kat, you need a master data model.

What’s Wrong with Revit?

We looked at each other from our plates filled and our glasses topped off by Autodesk. Is Kat suggesting architectural design is or should be departing from software created by the leading design software company in the world, software purported to be the do-all and end-all for architects? The master data repository is not the BIM model? Are Revit parametrics not good enough?

Undaunted, Kat proceeds to tell us all the benefits of a master data model combined with BIM platforms.

The Lotte tower shape becomes a set of equations in a generative design and part of master data model. Having the shape stored as equations allows for rapid design exploration, something you could never do with Revit. AutoLISP, surprisingly enough, was found to be usable to handle the overall building form all the way down to the details needed for fabrication of the building materials.

image009Figure 5 – Glass panel types in the curtain wall.

Triangular facets, shown in Fig 2, were used to affect the transition between square and round, as each floor gets smaller to the top. Each triangular facet was unique except for its twin on the opposite side of the building. Each facet was subdivided into rectangular glass panels that had to be modified depending on their location and how they interfaced with the building’s diagonal grid of structural elements, for example. The master model held the full shape of the tower plus the equations defining every panel based on its location in the master model and was able to spit out a massive spreadsheet with the 3D coordinates and sizes of every one of the thousands of panels at the push of a button. Also, it could generate the steel structural support for the curtain wall and the building itself.

Having a master model allowed SOM designers not only to study many more variations in design of the overall form, but they could now do so without fear that they would be sending designers back to their drawing boards to redo their BIM details.

What About BIM?

You can almost see the thought bubbles above every architect in the room, “What’s wrong with Revit?”

While basic shapes, even lofts, are easy enough to create on CAD and while parametric BIM modelers like Revit can vary shapes, the cascade of consequences after each form change on the structure and fabrication details would have overwhelmed BIM software. The flexibility and creativity needed at the design stage makes Kat have to resort to a litany of software tools that will be made to work together.

For fully parametrized shapes, you will need programming. This is where AutoLISP comes in. Parametric software can vary a shape but not alter the type entirely. Kat found this to be a problem, when she wanted to consider one design variation that would change the top floor from round to rectangular. BIM couldn’t do it. And so were 3D BIM tools, like Revit and Dessau’s DK, pushed away. SOM seemed to let CAD back in the office, begrudgingly, but then only once the final shape was determined, for a lesser role than they were intended for: the recording of mundane details, creating, printing or publishing the floor plans.

Was CAD Our Prison?

Spreadsheets, equations and the data they generate, may have been more than the Design Night party-goers bargained for. “I’m not sure people got it,” said one architect after the talk.

Indeed, there was a lot to get. But even a glimpse of how a big architectural firm may now be designing big buildings could be of great value. If the past generation used sketches and scale models and the current one uses 3D BIM software, the future may belong to a decidedly less stylish set of equations and a wall of numbers.

Do you really want your most creative minds to be imprisoned by you tools, Kat seems to be asking. Or do you want to them to explore freely, unrestrained. Do you want to compromise your vision for the next billion dollar building (Lotte tower cost is estimated to be $2.6 billion) because your thousand dollar software wasn’t able to could not convey it?

Sufficiently shaken, the architects, about a third of the audience, have got to be thinking.

So much for my hard won mastery of Revit. Now I have to learn how to learn programming and design with spreadsheets. That is not what I signed up for. Maybe that’s fine for MIT grads and the billion dollar firms that can afford them. Surely, I can get by sketching out additions, a millionaire’s home, now and then I have to lay out a strip mall.

For the rest, the ones with a few decades of practice in front of them, Kat is their wake up call. You thought CAD was the pen in your hand but it was your handcuffs. I had to break out and so can you. I had to use AutoLISP, for Gods sake. I wanted to see what hundreds of designs looked like, not just a handful. And for every design, I wanted the details to fall out – for free.

Assembling a collection of tools, such as Kat’s–hers involving AutoLISP, Excel, Revit, Digital Project, Rhino and Grasshopper–may be attributed to the gifted individual or large firms, or be too kludgy to manage. Or pick any number of reasons to dismiss the message to go back to the comfort of the familiar. But first, take a look at what has become of us. How did we let homes are created in increments of standard sizes of plywood, in increments of 4 x 8 ft. How did our downtowns be composed of cities with rectangular shapes? Furniture and appliances that are flat so often that a curve become remarkable. Every century or so, a Gaudi or a Gehry shakes us up, become labeled avant-garde, and briefly recognized then put in their place in books while we go back to what we can easily create, whether it is with our CAD tools, our building materials, or our manufacturing ability.

Maybe it is time for us all to break out?

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