Sunday, October 19, 2014


It's time we got the pumpkin bulges going.  I had a pumpkin dome last year, but I want to try rebuilding it from scratch with a slightly different approach.

I call this my "pumpkin slice rig".  Basically we build the wedge again, but this time as a rig.  It's a point world revolve from plus 20 to minus 20.  Make it glass and untick "visible".  Now it's a rig.

I made a new subcategory of mass called "construction lines" and set them to red.  I can use model lines for construction because we aren't going to use them directly in any "create form" operations.

Create radiating lines in sets of 3.  These will host profiles, each based on 6 points.  Effectively cross sections through the outer shell of the dome/egg.

Two points define the middle of the curve, hosted on the middle red line.  One at the end, the other set in a fixed distance.  The NCP for this second parameter is reset to "segment length". And controlled by a parameter called "thickness".

I don't know why I started to build a bowl, when it's supposed to be a dome. No big deal, just had to rehost the end points onto the upper curve.  To create the bulge, the points on the two side spokes have to be pushed further in.  So I have another length parameter called "curve".  Add "curve" and "thickness" together to set the position of the inner side points (CT).

When you are happy with everything, set the red lines to not be visible.  Leave it to the end because they will grey out.

At this point I just loaded the family directly into the project and made a circular array.  Wanted to check it out before attempting the furter complications of nesting and repeaters.

Set up a view from the indside.  Looks a bit bare perhaps, not sure what I can do about that.  I decided to make the dome white. Going for something of a tent effect.

Something tricky was going on with the array.  Not sure why.  I identified a reference point that had not picked up its NCP parameter correctly, but that didn't fix the issue entirely.

I decided to move right along to the next stage: a nested repeater dome ...  using the double nesting trick again.  Mass into GMA into mass repeater.  There's probably a better way, but for now this did the job.

All the funny alignments went away.  Maybe mass families just work better with repeaters than with vanilla style manipulations within the project environment.  I'll keep an open mind on that one.

I added a rib down one edge of the dome segment family, with a radius parameter that bounces down all the way to the project.

I also decided to try rotating the dome so the seams line up with the lift towers.  That seemed to work and set me off on adding a bit of articulation to the cores.  A vertical groove and an egg-shaped finial.

I'm happy now.  The concept is hanging together.  The connection to Boullee is there, but we have a genuine pumpking, complete with bulge factors.  There is a definite middle eastern feel, but also modern.  Perhaps a hint of sci-fi even.

I wanted to try an lattice texture on the cresent-shaped faces of the base, but this proved a little difficult.  You can get curtain panels to cut nicely at the edges in the nested families,

but by the time they come through to the project they are spilling over the edges.

The compromise for the moment is to set the edges to "empty".  Which it is for my final render for this post.  The variation in texture is definitely worth having.

Wednesday, October 15, 2014


The clock is ticking, and as with any design project we have to stop buggering about at some point and make some firm decisions.  This is my design concept.  Pumpkin wedges, facing outwards, arrayed around the base of an elevated pumpkin.  Let's move on from concept to scheme design.

I think the next step will be to firm up on the scale and on the number of wedges.  Scale has two parts: overall scale, and relative scale of pumpkin to wedges.  This may be a fantasy, but there has to be a whisper of truth.  All good dictatorships know this.  Mask your lies with with the thinnest of veils of righteousness.  What am I talking about ?  The design must be informed to some extent by functional and structural considerations.  We need not be too strict, but without this element, it is not design at all, just wishy-washy day-dreaming.

3 things at the back of my mind.  I would like to bring more light into the bowels of the earth (the space under the bowl).  That bowl needs more convincing structural support.  We need a more convincing circulation plan.

But first let's rebuild the pumpkin wedges in point world.  They need to be masses if we are to play with floor plates and areas (ie test the scale) and the repeater concept will probably be a more robust way of making a scalable base.

So I'm going to use a box rig, but the wedge itself will essentially be built off a rectangular rig (the bottom surface of the box).  The rest of the box will be hosting the void cut.

I just need one formula, which expresses the height in terms of an angle.  (Tangent = Opposite over Hypoternuse ... ie Height over Width)  The length of the box (D because it was originally conceived as Depth) controls the length of the pumpkin wedge, which is a revolve.

The profile of the revolve is hosted on ladder rungs in the time honoured manner of my rectangular rigs.  Like any respectable revolve it has a start angle and an end angle.  Start angle is zero, end angle is a parameter.  I'm sure you can figure out what's going on from the pictures.

I made this as a mass family, then hosted it into a Generic Model Adaptive (GMA).  The GMA can act as a repeater component, also by nesting I can play around with the orientation of the pumpkin slice.  This is important because I have yet to find a foolproof way of ensuring that components will orient themselves in a repeater exactly as I would like.  Nesting allows me to go back and host my slice on a different reference plane.  It this case it needed to stand up on end, which is after all the orientation it had before it was sliced out of the pumkin and tossed to the ground.

In the master base family, I create a circle with a radius parameter.  Turn this into a repeater (actually the original model-line circle will also be retained as a separate object)  Host a slice, fiddle around till I get the orientation right, and repeat.

Now I can vary the length of the slices and the number of components to very easily play with different base configurations.  I chose to load this into a project and separately insert my egg family (the auditorium).

That way the base can be selected separately when creating mass floors.  Immediate feedback on the kind of useable area I can expect.

For the moment let's keep the number of slices constant at 9.  That number seemed to work well last time and it makes for an unsual geometry.  To create a gap between egg and slices, I will need alternative support for the egg (it no longer touches the slices)  I also need vertical circulation so let's start very simply with a series of rectangular lift cores. This is the second time I have come across wierd behaviour when takin a section through the exact centre of a revolve.

I was surprised by how quickly reducing the egg size spoils the overall composition. I don't want the slices to be too dominant.  Everything else should appear to be subsidiary and supportive to the egg/pumpkin.  Of course part of the problem has to do with placing the camera too close.  The nearer you approach, the more dominant will be the base, and the more the auditorium dome will recede as you look up at it, ever more steeply.

So I used a more distant camera to judge the relative sizes of the elements.  2 or 3 iterations produced an acceptable result.  Also this exercise justified my decision to keep the elements separate rather than try to do everything via on monstrous parametric family.  Keep it simple.  Focus on design.  Get the job done.

Looking at the section I decided to bring back the spokes idea from the octagon scheme, but make them more organic: a huge lunging arch.

Once again some drafting in section view helped me to think things through and quickly generated an image that could be used in design meetings.  We have accepted the idea of drafting for construction details.  Totally counter-productive to model screws in 3d.  Doesn't the same principle apply to early design.  Why try to model every detail of a concept that may get the chop next week ?

A similar approach applies to further comparisons of scale.  In my first post I looked at monumental scale via simplified massing models.  This was an appropriate approach at the time, but right now I want to put my auditorium in context and think about banks of seating.

So I dragged jpegs into my section, duplicated the view, dragged in some more.  How about Garnier's Paris Opera or Adler & Sullivan's Chicago Auditorium. The point is that Revit contains an embryonic Desk Top Publishing capability.  Personally I would like to see this side of the programme enhanced.  It would certainly appeal to designers.  Don't we want designers to be more involved in BIM ?

By doing the 2d, touchy-feely stuff within the BIM software it's easy to switch back to 3d.  So I created an in-place revolve, just 40 degrees with some embedded void extrusions.  Then I arrayed these around in a circle.  Quick and dirty, generate some images, stand back and reflect.

Want some plans ?  Now the automation of BIM comes into play.  And what do you know ...  the results are reminiscent of Boullee & Ledoux.  That same monochrome, figure/ground feel seems to have found its way into my pumpkin by osmosis.

This gave me a real kick and drove me on to work up some image-processed renders.

Do I have to justify these ?  Is there something un-BIM-like in spending an afternoon overlaying layers and applying artistic filters to what is essentially a static image, divorced from the intelligent model ?

Well I would love to see these kind of capabilities integrated into BIM authoring software.  But I don't see that happening any time soon.  In any case it sometimes help to take a break and do something different.  I've compared this before to playing a guitar song on piano.  Always throws up fresh ideas, new interpretations.

Notice the Albert Speer spotlights in my night shot.  Cathedral of light in the desert.

The Mirage version began as an attempt to reveal the inner workings using transparency and layering, get a feel for the relationship of the crypt to the dome above.

Sometimes it's good to spend the time layering up people and trees to flesh out an image.  Sometimes it's OK to keep things raw.  Just add some textural effects and express the drama of the space.  There are no fixed rules in the world of design.  Are BIM managers so fond of their rules that they can't get along with designers ?  I really hope not.  It's all about team work and we need to pull down the existing barriers, not erect new ones.

The final image is very, very simple, and almost monochrome, but I love it to death.  Somehow it evokes the cool grandeur of one of Boullee's magnificent etchings.  I'm starting to enjoy this.

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.