Highrise Skin

8/3/2019 Highrise Skin

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architects

PROCESS

from wood to glass and steel and back


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PROCESS

from wood to glass and steel and back


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The trunk of an ancient tree inspires the form of thebuilding.


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A nurbs* surface modeled to evoke the strength andprimordial nature of the twisted tree.

Development of NURBS (Non Uniform Rational Basis, or BzierSpline) began in the 1950s by engineers who were in need of a

mathematically precise representation of freeform surfaces like

those used for car bodies and ship hulls, which could be exactlyreproduced whenever technically needed. Prior representationsof this kind of surface only existed as a single physical model cre-

ated by a designer.

from Wikipedia


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Free form surface must be refined into into pure arcsand lines. To achieve this we first create section linesof the n.u.r.b.s. surface.

By analyzing these sample sections we can see the basicform of the building can be defined by the top, bottom, andthe middle sections.

*The name lofting comes from the shipbuilding industry. It wasfound that work done in the mold loft served a useful function in

constructions where parts with complex form had to be fitted to-gether to build a ship. The definition of the hull shape was done in

the loft over the shipyard, using enormous drawings. To provide asmooth longitudinal contour, points taken from desired cross sec-tions were connected longitudinally on the drawing using flexiblelead ducks (weights holding down a flexible rule).

Source:LOFTING AND CONICS IN THE DESIGN OF AIRCRAFT

The top, bottom, and the middle sections are traced withcircles and lines. This creates a geometry that can be con-structed with standardized modules.


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The standardized curves approximate the original form

By lofting* the standardized curves a surface is createdthat approximates the original


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The lofted surfaces are trimmed to reveal the basic shape


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At this point more detail can be added to the simplified sur-face model. Contruction lines for the three notches in theface of the building are created using the sample sectionsas guides


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The construction lines for the notches are lofted.


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Once again the surfaces are trimmed.


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Now that the simplified surface has sufficient detail sec-tions can be created from it that will inform the final con-

struction. We have created a horizontal section every600mm starting at the base of the surface and continuingto the top. This will be the Height of each level of glass thatmake the facade of the building.


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After the sections are created the simplified surface

can be hidden to reveal the sections. At this time the onlycurved objects in the sections are along the front of thebuilding. To further create a closer aproximation of theoriginal nurbs surface we can fillet the corners of the sec-tioins to a desired radius


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Although it would be possible to loft the simplified sur-face from filleted starting curves this is not advised, as the

curved sections may not maintain tangency to the straightsections throughout the loft.


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Although it would be possible to loft the simplified sur-face from filleted starting curves this is not advised, as thecurved sections may not maintain tangency to the straight

sections throughout the loft.


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Here are three different colored sets of arcs. Each colorrepresents a fixed radius. By filleting the disinct straightsections in this maner it is possible to limit the number ofdifferent curvatures required for the facade glass from infi-nate to six or seven.

Notice that when ratio of the angle of the intersection oftwo lines to the radius of the circle becomes too small it is

imposible for a fillet to form. This leaves a discrepency inthe surface the must addressed in detailing or by alteringthe geometry of the simplified surfaces.


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The filleted sections are extruded to reveal shape of the600mm tall panels of glass that will make up the facade. At

this point the length of glass as well as the radius requiredfor construction can be calcuated.


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The red areas illustrate areas of curved glass in the facade

Measurements of a section generated from the simplified

surface verify that the radii have remained constant fromthe bottom of the building to the top


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The arcs and lines defining the shape of the windows aredivided by a point every 1800mm starting from the left sideand moving right. These points are used to divide the arc

and lines to standard lengths for the glass. At the end ofmost arc and lines there is some length remaining that isindivisible by 1800mm.

If all of the full length 1800mm curves and arcs are hid-den it is possible to see the remaining pieces clearly.The remain pieces are the divided by a smaller moduleof 1200mm. Once again there will some left over length.

Ever decreasing modules can be used to divide the seg-ments into standard length. In this manor it will be possibleto order a finite number of distinct glass sizes. This shouldrealize cost savings in architectural and construction cost.


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Here is a proposal for modular glass sizes for the facade.This wall shows four sizes of glass each for four radii of

glass for a total of 16 glass modules. Evident in this imageare leftover gaps which require further resolution.

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