Tuesday, April 22, 2014


This is a quick and dirty one.  Maybe it'll lead somewhere, maybe not.  You can blame Matt Jezyk for this.  A comment he posted on Zach Kron's Pantheon dome (long back) caught my attention about 18 months ago (when most of this work was done).  This is the building Matt was referring to:  Saint Charles of the 4 fountains (my translation)  Just take it as a starting point for an exploration.

I started by sketching the basic idea.  Oval dome, divided service based on rectangular pattern, curtain panel by pattern

Next came a drafting view to figure out the basic tesselation and derive a spacing for the grid.  There are some root 2 values in there because of the octagon, so I used 4 decimal places.  It's nice to know that the reference lines in the curtain panel template follow each other around, so you can select 4 points and type in their position (fraction of 1).  Then select the next 4 and ditto.  Speeds things up a bit, but this stuff takes a while. 

Join them up in pairs to make a grid, turn these into reference lines so they don't show up in the host project.  Then there are lots more points to host on a line and move up to the crossing point using host by intersection.  More spline by point to join up pairs & eventually we get some loops that we can use to make geometry.  I opted for tube sweeps because that's the easiest and I wanted to test something out before investing more hours in developing a detailed solution.

The dome itself is made from 3 profiles placed at different heights and scaled appropriately.  I tried a couple of methods & the best way to get a continuous grid turned out to be using spline by points, 2 of them, one for each half.  Divided surface for each half of the dome uses a 2x4 grid,

Load the curtain panel component and populate the serface.  The result is quite interesting.  It cuts the corners, which is not good, but otherwise it is quite promising.  One of these days I will make an adaptive component with 9 points and use this to simulate a panel that wraps itself around the curve.

That's for the future.  Back to the past.  I wanted to put the dome into context, based on bits and pieces of reference material I've picked up over the years.

The geometry is typical Borromini.  Triangles, Circles, Elipses.  I mapped this out and placed the main columns.

But how high to make them?  I didn't have a section, so I did a bit of drafting over an internal photo.  It's a starting point at least.

Add a ring beam over the columns, an apse at one end and an arch at the other.  Then an ellipsoid ring beam to support my "divided surface dome"  Looking at it now the columns appear too short.

At this stage I usually take a couple of camera shots to compare my model to actual site photos.  Try to pick up mistakes in proportion early on.

That's as far as I was able to go at the time.  It's been sitting there waiting for long enough so I decided to share.  Makes an interesting complement to the St Ivo studies. I do hope I can find another weekend some time to take this to the next level.  It's a building that made a big impact on me as a teenager when I first started to take an interest in architectural history.  I haven't even started on the faced yet, which is the element that first caught my attention.  Virtuoso interplay of concave and convex forms.

But even this brief study has given me a much better understanding of this fascinating building.

Wednesday, April 9, 2014


Francesco Borromini, volatile, brooding, controversial ... one of my early heroes.  I've had a couple of goes at studying his work with Revit.  Not easy.

This one is St Ivo Sapienza.  Most of the work was done in August last year.  The well known feature is the dome, from inside.  The geometry is based on circles & triangles.

It's a chapel, built within an existing setting: the university of Rome, three stories around a courtyard. Situated between the Pantheon & the Piazza Navonna.

As usual with Borromini, one of the major themes is a play between concave & convex. solid and void, undulating forms that deceive the eye.

I built the dome as an adaptive family: two solids and one void. From the outside you see an upper dome (loft) sitting on a drum (extrusion), both with 6 lobes.  The third element is a lofted void, cutting through both solids to form the complexity of the internal dome.

The profile for the upper dome uses arcs with their centre marks switched on.  These slide up and down reference planes in response to a scaling parameter.  Three instances of the profile make a lofted solid.

The drum profile is points based: bold curves alternating with short flat sections. Just a simple extrusion this time.

The complex void that cuts away the inner dome was more difficult to set up.  Points based again, and using the circles-in-triangles idea.  There is a large equilateral triangle, set up with reference planes.  This constrains most of the points and defines the straight-line segments.  The mid-points of the curves slide up and down on radial ref planes.  There are 4 dimension parameters which are converted down to one overall dimension and two bulge factors by some simple formulae.

The result is a parametric form that is relatively easy to fine tune to get a close fit between the 3 elements and to adjust the thickness of the dome wall.  It's also fully scalable so it could be resized in response to new information as my research proceeded.  In the parent family all the linked parameters are expressed as multiples of a basic module "M".  Vary the module and the whole thing will scale proportionally.  Adjust the numbers in the various formulae and you can alter the proportional relationships.

Usually, in this kind exercise, I find that it takes a while to get to grips with the source material.  Very often the model is well advanced by the time I figure out a set of grids and levels that gives a reasonable match to the data.

That was the fancy, parametric part of the exercise.  From there I proceeded to develop the whole building.

As work proceeded I realised that this is a variation on the "squared circle" theme that has been used by many famous architects.  The Altes Museum by Schinkel & Stockholm Library by Asplund spring to mind immediately.

See how the repetitive rhythm of the cloisters draws the eye towards the complex form of the chapel, make this the focus of the whole composition. It also interests me that the exterior facade is relatively bland and business-like.  No need for outer show, except perhaps for the lantern over the dome.  The only element which can be seen from afar.

A perspective view looking down the court towards the chapel shows the rhythmic effect and the contrast between regular forms and voluptuous curves.  Important to note that I have not modelled everything in full detail.  As always this is a simplified abstraction, designed to capture the spirit of the original. LOD 100 perhaps.

I may come back and take it to the next level some day, but for now this is enought to give me a much deeper understanding of how the building works: its form, its construction, its functional relationships.

That's the power of BIM as a research tool.  The combination of 3d with orthographic, the parametrics, the documentation tools.

Whether you are doing historical research like this, or working on a live fee-earning project, BIM excels at forcing questions upon you as you work.  It's a great way of working, and I could not have achieved these results working in CAD.  I know because that's what I was trying to do about 15 years ago, but I had neither the time nor the patience to reach this kind of level of analysis using CAD tools.

I am constantly amazed by the last few diehards in our office who continue to use a disconnected workflow.  I know you can do wonders with xrefs & layers and the output these guys achieve is quite impressive.  But there's no way I would want to go back there and I have never met anyone who enjoys returning to CAD once they have achieved fluency in Revit.

But let's not fool ourselves.  A building such as this, with it's highly sculptural solid walls, is quite challenging to model.  It's tempting to model the walls in place, but then you lose some of the intelligence of the system wall tool.  Of course it's easy enough to "fake" a floor plan with 2d drafting and make it look convincing.  I can't help wondering how Borromini himself worked.  Obviously he drew by hand, but to what extent did he use physical models ?  How much did he actually figure out on site, directing the craftsmen with words & gestures ?  We know that Gaudi achieved the wonderful plasticity of his work by these kinds of methods.

So let's not get too puffed up about BIM.  It's a wonderful idea, but clarity of vision trumps software any day of the week.

Sunday, March 30, 2014


A couple of weeks ago I finally received my complementary copy of "Renaissance Revit" a wonderful book by Paul Aubin that came out late last year.  It came because Paul was kind enough to ask me to write the Foreword, and it was so long in coming because of the vagaries of the UAE postal system.

Over a year ago I had a bit of a go at modelling a corinthian capital in Revit.  It was an interesting exercise, and I was quite proud of my efforts at the time, but I have to say that Paul has been much more persistent and systematic in pursuing this goal.  In the process he has produced a major contribution to the "Broadening of BIM".

There is a rather sad tendency to see BIM in narrow business terms.  We allow our lives to be defined by time and money, percentage and profit.  BIM is just another nail in the coffin as we sit at our workstations like battery hens laying eggs on demand.  (Which is pretty much how I saw a career in architecture in my early twenties when I abandoned it to become a bricklayer, which seemed like a suitably subversive thing to do at the time)

I am carrying a torch for a broader definition of BIM: BIM as the new pencil, an all-purpose tool that can be applied in a wide variety of contexts, a vehicle for visual thinking.  Clearly Paul is also a firm believer in this wider vision.  This book is a wonderful way to achieve 3 goals simultaneously.

Master the intricacies of the Revit Family Editor
Gain a deeper insight into Classical Architecural Form
Broaden you vision of the uses of BIM

One thing I really like is Paul's open-ended approach.  Time and again he offers alternative methods and encourages the reader to make their own choices.  This is the opposite of rote learning (sadly too common in the "Teach Yourself Software X" genre)  But if you prefer, you can follow step-by-step instructions.  Paul has a very clear and relaxed style for guiding you through.

Not many will take the extreme approach that I did, but it's a tribute to his skill that it worked for me.  I took the liberty of skimming through large sections of the book and then striking off on my own from memory.  From time to time I had to dig back into the text for clarification, and the family I made was very different from any he presents, but it is also quite clearly inspired and informed by his work.  He took me to a new high over the course of a single weekend, with the promise of much more to come.

I spent a couple of hours drafting in 2d.  This is not part of the book, perhaps it could have been, but it was a response to Paul's deep insight into the proportions of classical mouldings, which really got me going.  Revit is a wonderful 2d drafting tool: much neglected in this area.  I sketched up 2 or 3 versions of the Tuscan order, based on photographs I have taken over the years.  Now there is no universal agreement on classical form and nomenclature, never has been.  In the end it all comes down to personal judgement of what is appropriate in a given context.  Paul manages to convey this difficult reality without sowing confusion.

Having clarified my ideas about what is fixed and what variable in a Tuscan column, I set about to make one.  Quite early on I decided to make a highly simplified version, suitable for schematic urban design studies.  This is the topic for one of my presentations at RTC Chicago in June, so it seemed useful to kill 2 birds with one stone.

I ended up with something intermediate between the coarse and fine versions that Paul incorporates within his Tuscan family.  I'll have a go at that another time.

One of the new tricks I learnt from this book is "Maximum Segment Angle"  I won't describe this in detail, (you need to buy the book), but it's a nice little trick. It gave me a method for switching between round & square versions.  I used a different trick to switch between column & pilaster (the sliding void)

Just like Paul's families, this one is a real column that responds to the floor-to-floor height by scaling itself up and down proportionally.  I started to place columns and pilasters on an imaginary building to demonstrate its versatility.

Then I decided to use a historical reference.  Why not Palladio.  Rather perversely, I then chose to embed the column inside another family, which somewhat negates the level-to-level approach of a Revit column.  Still useable though.  I'm developing the "buildings as families" idea for my Urban Design studies.  I started with Villa Piovene, slightly obscure, but an interesting location on a ridge overlooking a small town.  Turns out that Bing Maps shows this part of Italy at a much better resolution than Google Earth (by the way)

 Zoom in on the section at top right of the image above.  I was rather proud of that.  Justifies a BIM approach to history of architecture.

Next I decided to tackle Villa Saraceno, which sits on it's own in flat open farming country.  One of the fascinating aspects of Palladio's villas is the way they sit on their sites, how they relate to barns and other ancillary structures.  Different approaches in different contexts, but all recognisably cut from the same cloth.

That was one weekend frittered away.  Next weekend I found myself doing Michaelangelo.  Still taking an urban design approach, and starting with the Campidoglio, then putting it into context.  Before long I found myself mapping out the whole of central, historic Rome.  In a broad-brush kind of way.

I'm training myself to work fast, broad-brush, capture the essential structure of an urban composition as economically as possible.  Just a little insight into my preps for RTC Chicago in June.

But let's get back to Paul's book.   There it is sitting on my coffee table, filling my head full of tempting possibilities.  I'm going to get a lot of mileage out of this.  Here's another glimpse between the sheets.  (as it were)  Nice bit of fluting there.

If you would like to delve a bit deeper into the family editor, and / or   if you are a closet classicist ... get yourself a copy.  It's worth every penny.