Sunday, October 12, 2014


This is my fourth post, and represents the fourth iteration of a design process.  Stage one was just an exploration of scale, done the Revit way.  Second came the first design concept, "pumpkin in a square".  Learned a bit about using a parametric family as a design tool, but ultimately a failure.  Stage 3 was the octagon with spokes.  Much better, but is it good enough ?

What we need is unity, integration, pumpkinicity through & through, plus middle eastern to the core, not to mention fundamentally monumental.

I'm going to persevere with a smooth egg shape for a while longer.  It has a certain purity, and I don't want to get too distracted playing with pumpkin segmentation and bulge factors until I am confident about the supporting/surrounding elements.

A flash of insight early one morning while still in bed.  A pumpkin segment disembodied and laid down flat is a crescent.  How about arraying the dismembered parts of a pumpkin around in a circle?

I'm still steering clear of Point World.  Let's not get sucked into too much technical stuff.  Focus on design issues.

First of all, the crescent.  It's just a revolve with a start angle and an end angle.  Make it with splines and it will scale up with a single width parameter.  Each spline has 4 nodes.  One at each end and 2 in between to define the curve.  We can open it up and play with these to vary the curvature. At first I wamted to make it fully parametric, but decided not to get bogged down.  Easy enough to make manual adjustments and it reminds me to think like a designer.

This is all vanilla remember, so now repeaters, just a raidal array.    There's something odd about a circular array like this when viewed from ground level.

I started out with 5 segments appeared to be more than enough when viewed from above in parallel projection. But when seen from ground level in perspective the reverse is true.  After a bit of trial and error, I settled on 9

The next issue is about angles and keeping the egg suspended high enough.  Initially the crossing over of the end points was accidental as I played with the width of a single segment and the diameter of the whole array.

But realising that we needed to create a wide zone of structural support but eager to keep the full crescent shape visible, I decided that a crossover could work to my advantage.  In it's earliest incarnations, this idea involved placing an extra curved extrusion "behind" the points.  A clumsy solution.

A bit more trial and error led to the next breakthrough.  Take a segment that starts flat on the ground and cut away the middle with a wedge.

If we get the distances right, the overlapping ends will create satisfactory forms both front and back.  I am left with V shaped cuts that make natural entrance points and an interior space big enough to house lifts and perhaps escalators.

At this stage the family is not fully parametric.  I can't type in different numbers of segments and expect them to all adjust themselves convincingly.  But I can scale the whole thing up, so I did just that.

We have made some slight concessions to the law of gravity, but the pumpkin slices are not going to hold up the egg on their own.  How about some extra support in the middle ?  I imagined this as a thick circular wall punctuated by arches.  In family editor terms this means an extrusion cut by an array of void sweeps.

Later this developed into a double ring, and the void sweeps became blends so that we could have narrower arches cutting the smaller inner ring.  This was around the time when I completed my "Quarter Past Eight" post ... the time when 2015 R2 was bestowed upon us ... and I was able to take fully advantage of nudging in perspective view.

Let's treat this a bit like a real project.  Time is short and we need to get some images across to the client.  So let's take a break from family editor and all that parametric stuff.  For the exterior view, all we need is people and trees plus a bit of creative layering using image editing software.

The interior view also responds well to layering, and I've hinted at escalators with some 2d drafting.  A bit crude perhaps but it will do for now.

The section view is where drafting really comes into its own.  Masking regions give the impression of floor levels within the segments.  These will be exhibition galleries, a whole series of themed spaces looking over each other via triple volume edge spaces.  Levels linked by escalators and at least one of them continuing right around in a full circle.  The egg itself is an immense event space.  Lasers conjour up holographic representations of past civilisations: ancient sumer, egypt, catal huyuk and jerico.  This is the signature show, playing several times a week, but there are also seasonal events, concerts, plays, circuses, opera.

Underground there are more galleries, and extensive research facilities, specialising in the ancient middle east and the genetics of domesticated plants and animals.

Those images were created on 19 sept and that's the point at which I decided I had something worth sharing, and wrote the following.

So what is the verdict on pumpkin-land version 3 ?  Could be a goer.  With the time available I have to run with it.  I think it is strong enough.  Remains to be seen what I can make of it.  What happens if we introduce seams ... ie convert the egg into a pumpkin.  Will it remain a strong concept ?  I think it has a much better chance than the previous 2, but the only way to find out is to do it.

Actually it might help to unify the base and superstructure.  We have seams where the crescent/segments cross over, so why not echo these in the dome?

I am also thinking about materials and construction now.  The bowl of the auditorium has to be concrete. What about the dome?  I am thinking steel truss ribs supporting a lightweight shell.  In Dubai, domes are commonly made using GRP sandwich construction with a lighweight foam core.  For the moment let's just imagine an array of lightweight shells, perhaps a metre thick with a really stupendous U value.

There is going to be a seam between bowl and dome.  Let's not try to hide it.  Think of a jack-o-lantern.  You slice off the top to scoop everything out, then put it back on again.  It has a seam, express it.  In this case it will be much lower down, no matter, same principle.

Other organic references spring to mind.  Peeling back a banana skin perhaps, or the outer leaves of some exotic vegetable. What about an acorn ?  That has an upper dome and a lower bowl.  There must be a clue here somewhere to handling the transition.

Fenestration will be another big issue.  How to treat the inclined crescent shaped surfaces so that they can let some daylight into the interior ?  I think perhaps a continuous horizontal texture will be best.  Think louvres.  Or maybe a musharabiya pattern of some kind.

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