Hyperbolic Paraboloid Buildings

Ever since I first stumbled upon them in "A Visual Dictionary of Architecture" I've been fascinated with the concept of hyperbolic paraboloid buildings.

Essentially a hyperbolic paraboloid is a structure which, in some frame, is described by the equation

z=x*y

If you slice it along constant z you get

1~ x*y or y~1/x or x~1/y

If you slice it along a line y=k*x you get

z=k*x*x or z=k*x²

But the part that makes it useful as a surface for buildings is that if you slice it along constant x or constant y you get

z~x or z~y

in other words, a straight line.

For this reason, it is called a "ruled surface", and a framework for it can be made entirely out of straight beams, as in the pictures from this site

http://www.savetrees.org/Hyperbolic%20Paraboloid%20roof%20shelter.htm



One problem with such a surface is that, while it is easy to construct the frame out of straight beams (and the resulting structure is known for its strength), constructing the roof to fit into the frame is non-trivial, especially if the surface must be hard.

It is *possible* to construct something that mostly fits snugly over it by cutting pieces out of a cloth tarp (as shown in the above link), but any patch of the true surface of the object is curved (as well as any line which is not constant in either x or y)

One solution might be a "concrete tent" similar to what is proposed in this article
http://www.wired.com/science/discoveries/news/2005/03/66872 (start with a "tarp with sections cut out" and brush wet concrete over it. Then let the structure harden)

Another alternative might be to layer a fine mesh of straight wires along constant x and constant y, and take some goopy filler material, such as plaster, and brush it over the wire mesh. I wonder if something like this is how they make permanent buildings with hyperbolic paraboloid roofs. Some of the images of such structures certainly look like a wet material was painted on top of a mesh and then allowed to dry, although larger hyperbolic paraboloid structures, such as the Catholic Cathedral on Gough Street in San Francisco, are often clearly made from piecewise surfaces (float or otherwise). I think to have a piecewise surface of flat segments perfectly conform to a frame of straight segments in such a roof, the segments have to be triangles (and highly irregular ones at that!)

Re-posting an interesting idea.

Re-posting
http://robotmonkeys.net/2010/07/22/bullet-train-hopping/

Jonathan writes:

"Jianjun Chen in China proposed an interesting idea for eliminating station dwell times for trains. In his/her design, each train has a detachable boarding shuttle mounted on the roof of the train. Passengers who wish to disembark leave the main passenger compartment of the train, and enter the shuttle. Meanwhile, embarking passengers board an identical shuttle already located at the station. As the train approaches, the shuttle mounted on the train, disengages so it can slow to a stop at the station, while the shuttle is grabbed and mounted onto the moving train."

http://earthobservatory.nasa.gov/IOTD/view.php?id=44717&src=eorss-iotd

You can see Santa Cruz (and the rest of redwood country) on this map.

The right approach, I think

http://www.oxygen.lcs.mit.edu/Overview.html

Having glanced through the websites of several "ubiquitous computing" research groups, I think that the Oxygen project at MIT is the closest I've seen to "something on the right track" Partly I occasionally track / glance at what's happening in this field because I think it could become an interesting thing to be involved in in the future. Partly I keep looking at it because I have this sneaking suspicion that, when we start getting to pervasively embedded small computers, HCI will start looking like a robotics problem. And partly I'm interested in how the network connectivity for pervasive computing might work : perhaps the distributed robotics and ad-hoc network people have a head-start on some of the issues that might come up.

Should be of interest to some

Particularly of interest is the discussion of the "software as object" focus

http://www.shirky.com/writings/group_user.html

Group as User: Flaming and the Design of Social Software

On band.

I was sitting home sick, watching youtube videos

http://www.youtube.com/watch?v=qybUFnY7Y8w
http://www.youtube.com/watch?v=PxANVR07GVI

(who does their videos, by the way? Pete would probably know.)

when I came across
http://www.youtube.com/watch?v=EltW4w2W_Ys and I started thinking about my "high school band" days, and how our sound always sounded so *mushy* and I had the recurring thought "If the band's seating is 100 ft across, and sound travels at 1000 ft/sec, the clarinets should hear the trombones be off by 1/10th of a second -- or, at 120 bpm, 1/5 of a beat."

I mean, I'm sure skilled musicians (not me at the time) compensate for this in a variety of ways : but any form of compensation you could have only "works perfectly" for at most one spot (2 spots if the band is aligned precisely along a line). It seems like the "best" you could do is "everyone plays off the conductor's baton" (information from this travels at the speed of light) and for a listener at a large distance, l, from the center of the band, to whom the band is aligned perpendicularly, hears different instruments as if they were at most

sqrt(l2 + 2500) - l

feet apart, which, as l gets large, behaves sort-of like (1/(2*l)])*2500. Or, better yet, pick the spot (the king's chair?) at which the sound has to be perfect, and align the entire band along the rim of a semicircle with that spot as the center (somewhat close to what bands and orchestras actually do).

But still, the time delay to to sound travel when you're sitting inside the large band/orchestra means that musicians can't really react to each others sound they would in a small ensemble. In essence, they have to rely on the (centralized?) conductor for synchronization. Which is probably yet another one of the many reasons why groups that do real improvisation tend to be small.

Also, that guy with the monocle in the elite box off to the side? He's probably hearing one of the worst orchestral performances of his life.

I have a weakness for far-off space station designs

Cool

http://lifeboat.com/arki/design-construction.shtml

I'd live in one. I like the whole modular-architecture aspect to it as well.

Not as expansive or ambitious, however, as :
http://en.wikipedia.org/wiki/Island_Three

Cool devices my friends have pointed out to me.

http://en.wikipedia.org/wiki/Monome


http://en.wikipedia.org/wiki/Chumby

Cool concepts:

http://en.wikipedia.org/wiki/Ambient_device
http://en.wikipedia.org/wiki/Ubiquitous_computing
http://en.wikipedia.org/wiki/Internet_of_Things
http://en.wikipedia.org/wiki/Cyber-physical_system
http://en.wikipedia.org/wiki/Ambient_intelligence
http://en.wikipedia.org/wiki/Physical_computing

These are all mostly unrelated to monome