Tag Archives: innovative architectural technologies

Federal Triangle

USC/CW/ICC Modernization 1994

The Arthur Mellon Auditorium (ICC Building) 1994

Here is a composite drawing of the first really huge (HUGE) building that i used photogrammetry to measure and draw back in 1994.  This work was completed with Ben Frombgen at IAT when we were based in New Haven, CT. We did a complete set of elevations, eleven building profiles (that were later turned into building sections by our client, RTKL) plus a window schedule. It hurts for me to remember how little we charged for this work!  But it was one of our first big commissions and it seemed like a lot at the time.

This is also the first project on which I used a laser measuring device.  If I recall correctly, we were asked to deliver this project in metric units.  I remember being thrilled that the Leica Disto that we bought back then (which was as big as a large box of spaghetti) could switch between units.

I remember also that we had access to a great set of San Francisco based architect Arthur Brown Jr.’s original design drawings (from the 30’s) that were just stunningly beautiful and provided such a contrast to the general level of quality in CAD drafting at the time. Not only was the quality of drafting so great (a beautiful hierarchy of line weights, crisp fluid clarity of description) but the organization of the drawing set was so intelligent and efficient.  We resolved to find a way to draw as well with a computer and have been trying to do so since!

Arthur Brown Jr. also designed the san Francisco City Hall and Coit Tower.

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Photogrammetric Analysis

Photo with reseau and digitizing puck

Photo with reseau and digitizing puck

Analyzing stereo-pairs of photographs is a matter of locating the same precise point as it is captured in two or more photographs. In the old days, this meant using a digitizing puck to magnify and locate the x,y location of a point (relative to a set of cross hairs that were essentially coplanar to the film).  Today, with digital photographs, it is a matter of specifying pixels.  In both cases, a handful of these comparison points is needed to construct a geometric model for each camera station: each point becomes the terminus of a theoretical “ray” that passes through the focal point of the lens.  When the precise nature of how light passes through the focal point of the lens onto the film plane (or digital sensor) is understood mathematically, then this geometrical model can be quite precise, allowing for an accurate “back calculation” of the relative relationship of the camera from on photo station to another.

Its uncommonly difficult to write about – when you see it “happen” it is a little easier to understand!

wire frame diagrams of point cloud and camera stations

wire frame diagrams of point cloud and camera stations

Today, this whole process is becoming more and more automated, allowing for the creation of very rich point clouds when needed – or quickly creating smaller “smart point clouds” when the goal is a vector line drawing of a building, for example.

Photogrammetry and Stereoscopy

Ocean City City Hall (Left)

Ocean City City Hall (Left)

Ocean City City Hall (Center)

Ocean City City Hall (Center)

Here are two photographs from a project that IAT completed at the Ocean City City Hall in Ocean City, NJ.  These were shot using a Leica R5 which had been modified for use for photogrammetry. A thin glass plate with an array of cross hairs was inserted between the focal point of the lens and the film.  This was required for a good camera calibration. (Nowadays with digital SLR camera bodies the cross hairs – or the “reseau” – is no longer required.)

The basis of photogrammetry is “stereoscopy”, or simultaneously viewing the same subject matter from two vantage points.  So these two shots capture the same facade from positions to its left and center.  They are not shot simultaneously in fact, but sequentially – but in the life of a building they reflect more or less the same instant in time.

Additonal photographs from yet more unique camera locations can be included in a photogrammetric study, so in fact this technique goes well beyond stereoscopy which, technically, is limited to only two views. But for the sake of understanding what is happening in photogrammetry more easily I’ll only talk about two or three views for the moment.

IAT and creating measured drawings of really large buildings

iat-ICC_01After returning to the United States in 1992, I started a company with my friend and fellow architect, Ben Frombgen. We were based in New Haven, CT, and the company was called Innovative Architectural Technologies (IAT).  I am nearly certain that we were the first photogrammetric service bureau in the nation.

This was a challenge.  At the time, out-sourcing was not very common among architects.  A lot of architects were yet to start taking advantage of computer aided drafting software (CAD).  And we were complete novices at running a business!  One of our first big breaks at the time was landing a job with RTKL to do measured drawings of one of the buildings located in the federal triangle.  It was a huge project and we delivered everything on time.  The drawings were detailed enough to provide a unit by unit survey of this magnificent stone structure.  I remember that we had to do everything in metric units and that this requirement was what pushed us to buy our first laser.  It was a Leica Disto, which could provide accurate measurments in english or metric units. Back then the Disto was about the size of box of spaghetti.  I’m now on my third or fourth Disto; they keep getting smaller and more powerful.

Hand-held Laser Measuring device

Hand-held Laser Measuring device