13 ms·

What I find the most amazing about this whole thing is that it was designed by the same architect as the "death ray" building in Las Vegas. You would think the

by arscan 13y ago

What I find the most amazing about this whole thing is that it was designed by the same architect as the "death ray" building in Las Vegas. You would think they would have learned from their mistake. http://www.businessinsider.com/architect-behind-the-walkie-talkie-building-2013-9 http://www.businessinsider.com/architect-behind-the-walkie-t...

moomin 13y ago
Yeah, it's hard to describe it as unforeseeable when it's happened to you before and is readily modelable.
- johnchristopher 13y ago
  The guardian states this phenomenon is difficult to model: http://www.theguardian.com/artanddesign/shortcuts/2013/sep/03/walkie-talkie-death-ray-buildings-heat http://www.theguardian.com/artanddesign/shortcuts/2013/sep/0...
  - stephencanon 13y ago
    Whatever the guardian says, it's a very basic optics problem, and not at all difficult to model. It's mostly a matter of whether or not anyone bothers to do it.
    - mikeash 13y ago
      In terms of difficulty, it's one step harder than modeling which direction something will fall if someone drops it off your building.
      - lucisferre 13y ago
        Well except you have to model the position of the sun for every hour and day of the year, but sure other than that just like it.
        wmeredith 13y ago
        Or you could use a simple rule of thumb. Something like, "Let's not build skyscrapers that are giant parabolic reflectors aimed at things of value (people, cars, other buildings, etc.)" This seems like a really stupid mistake to make. TWICE.
        jcampbell1 13y ago
        ...or you could put the concave side on the North. That also solves the problem.
        bodhi 13y ago
        Then you build one in the southern hemisphere. Oops!
        dsuth 13y ago
        In the southern hemisphere everything is upside down too, so the rays would reflect off into the atmosphere, I expect.
        mikeash 13y ago
        I bet a modern calculating machine could run through all of the permutations in no more than a couple of weeks!
        deleted 13y ago
        [deleted]
        jlgreco 13y ago
        No way, it would be near instantaneous. Position of the sun in the sky is really trivial stuff. Hell, don't even bother, just use this: http://aa.usno.navy.mil/data/docs/AltAz.php http://aa.usno.navy.mil/data/docs/AltAz.php
  - jerf 13y ago
    It may be difficult to model precisely what will happen because of the little fiddly sub-millimeter differences in window positions mattering. It is not difficult to understanding that a generally concave surface facing the sun is very likely to have some sort of significant problem. To the extent that the exact result is hard to model, simple engineering prudence would suggest the "'Doctor, it hurts when I do this.' 'Don't do that then.'" response.
    - marvin 13y ago
      Yeah, this really seems...kind of obvious. A concave reflective surface will focus any light source, and in particular, the sun.
  - berkut 13y ago
    It's not - given an accurate geometry model and reflective window material, it'd be really easy to use a raytracer to test this: * Renderers like Maxwell handle caustics nicely, and you could get away with rough photon-mapping (instead of time-consuming but very accurate MLT) * Most renderers have very accurate physical sky light models which accurately model the intensity and position of the sun in the sky based on time of day and long/lat coords. It'd be easy to python script a run of renders for each minute in the day (10 seconds for a render) over the next 5 years and then run an analysis of the rendered image for intensity on the ground. Just set the ground material to not be lit by any diffuse GI rays or direct lighting, and it would literally just render out the reflected sun on the ground (or off other buildings if you wanted to do it REALLY accurately). It'd be time consuming and CPU intensive to do the rendering for all that: 2,630,880 renders for each minutes for 5 years, but you could probably work out an envelope you could skip (definitely the night time) after doing the first year. 7308 hours render time for the full 24-hour period for 5 years. But do-able, and very parallel over multiple machines.
    - sampo 13y ago
      You know, indirect lighting surely doesn't melt plastic, so you absolutely don't need Metropolis Light Transport here. And also you don't need to use photon maps. The computations to map the intensity of specular reflections from the building's windows would the equivalent to creating a photon map on a scene, not using the photon map to render a complete scene.
      - lutusp 13y ago
        > You know, indirect lighting surely doesn't melt plastic ... That depends on the light's intensity. If with the term "indirect" you include specular and diffuse reflection, then yes, in the right circumstances, the energy level can be spectacularly high. But computer simulations need to be done very carefully, because the issue isn't visible light reflection, it's infrared reflection. For the building in question, the windows are glazed with a coating meant specifically to pass visible light to the interior but reflect infrared radiation (both to preserve building heat in the winter and reject heat in the summer). What that means is that, as bad as the reflected visible glare seems to those passing by, the infrared energy levels are much higher, and easily explain the damage.
- mseebach 13y ago
  Everything is obvious once you know the answer.
  - SiVal 13y ago
    This is true, and we often forget it. But since they knew the answer after the Las Vegas building, the risk that this might happen should have been obvious.
iMark 13y ago
I wonder if the differing climates between Las Vegas and London played a part.
ohwp 13y ago
Had to think about the same Las Vegas building. But the Vegas one even has a curve. So there is a potential lethal focal point. Sensational news item: http://www.youtube.com/watch?v=R-hV_AawLSE http://www.youtube.com/watch?v=R-hV_AawLSE
- TsiCClawOfLight 13y ago
  this one also does..
Roboprog 13y ago
Perhaps as a child he had a fatal attraction towards frying ants on sidewalks with lenses?
Irishsteve 13y ago
Glass is cool
jessaustin 13y ago
"Within 30 seconds, the back of my legs were burning. My first thought was, 'Jesus, they destroyed the ozone layer!'"
shawn-furyan 13y ago
Here's your xenophobic headline: "Uruguayan National Responsible for Construction of Solar Death Rays in Major US and UK Cities"
VladRussian2 13y ago
one can only wonder how so many minutiae things can violate building code while a huge death ray building is just fine with the building department.

by arscan 13y ago

moomin 13y ago

Yeah, it's hard to describe it as unforeseeable when it's happened to you before and is readily modelable.

johnchristopher 13y ago
The guardian states this phenomenon is difficult to model: http://www.theguardian.com/artanddesign/shortcuts/2013/sep/03/walkie-talkie-death-ray-buildings-heat http://www.theguardian.com/artanddesign/shortcuts/2013/sep/0...
- stephencanon 13y ago
  Whatever the guardian says, it's a very basic optics problem, and not at all difficult to model. It's mostly a matter of whether or not anyone bothers to do it.
  - mikeash 13y ago
    In terms of difficulty, it's one step harder than modeling which direction something will fall if someone drops it off your building.
    - lucisferre 13y ago
      Well except you have to model the position of the sun for every hour and day of the year, but sure other than that just like it.
      - wmeredith 13y ago
        Or you could use a simple rule of thumb. Something like, "Let's not build skyscrapers that are giant parabolic reflectors aimed at things of value (people, cars, other buildings, etc.)" This seems like a really stupid mistake to make. TWICE.
        jcampbell1 13y ago
        ...or you could put the concave side on the North. That also solves the problem.
        bodhi 13y ago
        Then you build one in the southern hemisphere. Oops!
        dsuth 13y ago
        In the southern hemisphere everything is upside down too, so the rays would reflect off into the atmosphere, I expect.
      - mikeash 13y ago
        I bet a modern calculating machine could run through all of the permutations in no more than a couple of weeks!
        deleted 13y ago
        [deleted]
        jlgreco 13y ago
        No way, it would be near instantaneous. Position of the sun in the sky is really trivial stuff. Hell, don't even bother, just use this: http://aa.usno.navy.mil/data/docs/AltAz.php http://aa.usno.navy.mil/data/docs/AltAz.php
- jerf 13y ago
  It may be difficult to model precisely what will happen because of the little fiddly sub-millimeter differences in window positions mattering. It is not difficult to understanding that a generally concave surface facing the sun is very likely to have some sort of significant problem. To the extent that the exact result is hard to model, simple engineering prudence would suggest the "'Doctor, it hurts when I do this.' 'Don't do that then.'" response.
  - marvin 13y ago
    Yeah, this really seems...kind of obvious. A concave reflective surface will focus any light source, and in particular, the sun.
- berkut 13y ago
  It's not - given an accurate geometry model and reflective window material, it'd be really easy to use a raytracer to test this: * Renderers like Maxwell handle caustics nicely, and you could get away with rough photon-mapping (instead of time-consuming but very accurate MLT) * Most renderers have very accurate physical sky light models which accurately model the intensity and position of the sun in the sky based on time of day and long/lat coords. It'd be easy to python script a run of renders for each minute in the day (10 seconds for a render) over the next 5 years and then run an analysis of the rendered image for intensity on the ground. Just set the ground material to not be lit by any diffuse GI rays or direct lighting, and it would literally just render out the reflected sun on the ground (or off other buildings if you wanted to do it REALLY accurately). It'd be time consuming and CPU intensive to do the rendering for all that: 2,630,880 renders for each minutes for 5 years, but you could probably work out an envelope you could skip (definitely the night time) after doing the first year. 7308 hours render time for the full 24-hour period for 5 years. But do-able, and very parallel over multiple machines.
  - sampo 13y ago
    You know, indirect lighting surely doesn't melt plastic, so you absolutely don't need Metropolis Light Transport here. And also you don't need to use photon maps. The computations to map the intensity of specular reflections from the building's windows would the equivalent to creating a photon map on a scene, not using the photon map to render a complete scene.
    - lutusp 13y ago
      > You know, indirect lighting surely doesn't melt plastic ... That depends on the light's intensity. If with the term "indirect" you include specular and diffuse reflection, then yes, in the right circumstances, the energy level can be spectacularly high. But computer simulations need to be done very carefully, because the issue isn't visible light reflection, it's infrared reflection. For the building in question, the windows are glazed with a coating meant specifically to pass visible light to the interior but reflect infrared radiation (both to preserve building heat in the winter and reject heat in the summer). What that means is that, as bad as the reflected visible glare seems to those passing by, the infrared energy levels are much higher, and easily explain the damage.
mseebach 13y ago
Everything is obvious once you know the answer.
- SiVal 13y ago
  This is true, and we often forget it. But since they knew the answer after the Las Vegas building, the risk that this might happen should have been obvious.

iMark 13y ago

I wonder if the differing climates between Las Vegas and London played a part.

ohwp 13y ago

Had to think about the same Las Vegas building. But the Vegas one even has a curve. So there is a potential lethal focal point. Sensational news item: http://www.youtube.com/watch?v=R-hV_AawLSE http://www.youtube.com/watch?v=R-hV_AawLSE

TsiCClawOfLight 13y ago
this one also does..

Roboprog 13y ago

Perhaps as a child he had a fatal attraction towards frying ants on sidewalks with lenses?

Irishsteve 13y ago

Glass is cool

jessaustin 13y ago

"Within 30 seconds, the back of my legs were burning. My first thought was, 'Jesus, they destroyed the ozone layer!'"

shawn-furyan 13y ago

Here's your xenophobic headline: "Uruguayan National Responsible for Construction of Solar Death Rays in Major US and UK Cities"

VladRussian2 13y ago

one can only wonder how so many minutiae things can violate building code while a huge death ray building is just fine with the building department.