Sunday, January 26, 2014


This is a continuation of the last post about Steel Windows.

So I got the handle done & it rendered up nicely.  Next in line was the peg stay for a top-hung light.  (sash, light, casement ... what's with all these seemingly interchangeable words ... truth is that's just the way language works: lot's of redundancy & overlap, constantly shifting ground, rules that bend)

I was still feeling may way into these components, modelling by trial and error, but by the time I got to the screws I decided to make a separate family that could be copied around.

It was actually rather fun trying to model from memory and then finding references on the internet to guide me through the confusion.  You can use something a thousand times and think you know it well, but drawing it out in detail is another matter.  Try drawing a map of the world from memory for example.  Any teacher knows this very well.  You don't just stand there and talk to your students.  You have to get them doing something that challenges their abilities and understanding.

So I've captured the basics of these brass fixtures.  The dimensions are still very approximate, and to be honest I'm still not 100% sure how some of the moving parts work.  i.e. how are they held securely in place while permitting angular movement ?  This has to be done with the minimum of fuss, allow for manufacturing tolerances, plus wear and tear.  Low tech by current standards but 100 years ago these were important contributions to daily life.

There are fixing lugs on the sides of the windows that are built in to the wall by the bricklayer.  I'll do another post sometime on how this works, something that was once a part of my daily routine.  For now I am content to make a family that cuts a hole in the wall and place my window into this.  I'm keeping the two families separate for the moment to reduce my confusion while working in family editor.  The opening family uses voids (not cut openings) This allows me to step the opening in plan and section. 

The sill detail I chose is fairly common in Zimbabwe.  It uses special, small size clay bricks with a bullnose edge, sill bricks in fact.  I modelled whatever is visible from the outside, to a reasonable degree of accuracy, and filled in the hidden detail with drafting.  Classic BIM methodology.

A short aside.  Many of you will be familiar with the ribbon glitch that has been with us for some time now.  While making a sweep and clicking on "edit profile", the buttons you want disappear.  You'll see a greenish tab at the back, click this to restore normality.  I'm assuming this is a rogue behaviour that is difficult to track down in all the lines of code.  That's better than believing that the factory can't be bothered to fix it.  While working on this study, I noticed that this problem only occurs when working in plan view.  If you're working in section/elevation everything works fine.  Curiouser and curiouser.

More benefits of the BIM pencil: throwing views on to sheets.  This always draws a gasp of amazement when teaching newbies, and rightly so.  I've said it before, but Revit is my favourite DTP software ... but it could be even more favouriter, if only they would add some extra DTP features with each new release (hint to the factory)  By the way, see how I am adding subtleties of expression by bending/breaking the rules of language.  We all do this, all the time ... but if you're a secret language pedant, you just block it out and pretend that language is strictly logical.  Duhh !!!

And so to the end of my post. (no verb in that sentence, nor in this one actually)  I rounded it off by assembling a window with side-hung, top-hung and fixed panes.  It's a standard type from the catalogues but it's not fully parametric & the opening is still separate from the glazed frame.  Still it serves my current purpose amirably: fit for purpose, the golden rule.

I have a couple of images of the hinge family that I made, so I'll throw those in to finish off.  Timber sashes and standard steel windows, that covers the types of building I lived in for most of my life.  So I guess aluminium sliders are next, that's what I've had for the last 10 years, here in the middle east.


Wednesday, January 22, 2014


Steel takes an edge.  For centuries it was the material of tools and weapons: carpentry, warfare & agriculture.

I grew up in South Yorkshire while it was still a land of coal and steel. For most of my twenties I lived in Sheffield, birthplace of crucible steel, and later the of the Bessemer process.  By 1850 steel had become the material of bridges, machines, railways.  Cast iron predated steel for structural use in buildings, notably in "fire-proof" factory construction.  Cast iron columns carried beams similar to railway lines in section, with brick jack-arches spanning between the beam

5 or 6 years ago I photographed some of the famous cast-iron facades in Soho, New York.  These were an early example of prefabrication: modular facades created in the factory and assembled on site.  It's interesting to note that behind the decorative/structural cast iron there are often timber sliding-sash windows. 

One of the best known examples is the Singer building.  It seems to me though that much of this is not cast iron, but steel: heated and bent, riveted together.  Even the window frames seem to be steel. We are approaching an era when steel seemed to be the ideal material for window frames, and glazing of all types.

Charles Rennie Mackintosh got in there early, using steel windows in 2 school buildings in Glasgow (Scotland Road & the School of Art)  Is he a modernist or a traditionalist ? abstract geometrist or arts & crafts flower person ?  Nobody seems to be quite sure.

Just over a decade later Peter Behrens and his former employee Walter Gropius designed buildings that have become famous for their steel-framed glazing.  Technically I think this is very similar to Mackintosh, but they did without his subtle decorative flourishes and projected the glazing in front of the masonry.  So everyone is quite cetain that they are modernists.

Mass-produced steel windows in standard sizes, ("off-the-shelf") became very popular in the 20s and 30s, rapidly replacing the wooden sliding sash.  But the heyday of steel windows in Europe lasted barely 50 years.  Disruptive innovation or blip on the screen?  By the 1970s it was clear that condensation related corrosion was a serious problem, and U values were becoming important.

So when I moved to Southern Africa in 1981, I thought of steel windows as an anachronism, an outmoded technology.  But in a dryer and warmer climate, where neither central heating nor air conditioning are needed in the average house, steel windows dominated the market.

I spend my first decade in Africa as a teacher & curriculum developer, returning to architecture as I approached 40.  As an architect, I used steel frames most of the time.  They are the ideal solution for the Zimbabwean climate and economy.  (We used to have an economy in the first 80s & 90s)

So this is the next installment in my "window technology" series, standard steel windows: the Crittall Hope variety.  I should explain once more what I am doing.  For BIM to really succeed it must become second nature to all participants in the Construction Industry.  We should use it as naturally as picking up a pencil, or sketching a detail in chalk, on the wall inside a building site.  So my focus is not to track the latest devices and software tools.  Others do that much better than I could.  I am trying to use Revit like a pencil: a tool with which to explore ideas, clarify my thoughts, make sense of what I have learnt over the years; in short, an aid to visual thinking.

I am using BIM techniques to explore how buildings work, how they have varied in time and place, the processes and trades involved in making them.  I am NOT making families for everyday use in projects.  That is a separate exercise.
Typically, an experts advice on making families will start with an injunction to plan ahead, to sit down with pencil and paper to plan out the parameters and reference planes you will need.  That is not what I am about here.  Revit IS my pencil, my planning tool.  I am using it to work something out.  In the case of the brass handles and stays, or the steel hinges, there are elements that belong to the sash and elements that belong to the outer frame; elements that move in space and elements that stay where they are.  There are pivot points and angular movements.  Ultimately it would be nice to articulate all that, to make it parametric and represent top-hung or side-hung lights with the sashes in different positions by punching numbers into dialogue boxes.

 But first I need to understand how these things work.  I have to get the sizes and shapes right.  That is an exploratory process.  I don't have any steel windows to hand.  I can't just fly back to Zimbabwe and measure the ones in my house there.  I have to work from grainy photographs and internet downloads, plus my memories of fiddling with windows that didn't close properly or had loose handles.

Let's take the handle for a side-hung sash.  A door handle sits in a horizontal position when at rest, but you don't want the window handle to spoil your view, so it hangs down when the window is closed.

In making this handle, I wanted it to look fairly convincing, without getting sidetracked by Revit technicalities.  The goal was to understand the main points of the design: how it works and why it is shaped like that.  So  I haven't rounded off all the sharp edges and I haven't gone to the trouble of using conceptual massing to capture the complex curves.  I made do with an extrusion cut by a couple of voids.  Building components should be "fit for purpose", not under-designed or over-designed.  The same goes for drawings: be they pencil sketches or BIM models.  (I could have said "BIMs" but I think that would have been both clumsier and less clear)  So my aim here is to do just enough to capture the essence of how these fittings work. 

But let's look at the window itself.  If you look in text books, you can find all kinds of refined details, with weather stripping and aluminium glazing beads.  Steel windows been reborn in a higher-tech form.  But this post is staying low-tech, the basic window that I know from my time in Zimbabwe.  Standard "Z" section, putty glazed.  The same "Z" section serves for outer frame and for hinged sash.

 Notice the little heel on the back of the "Z".  This forms a groove to channel water around the sides. In case of driving rain, you might get some water that needs to be directed in this way to the bottom and out again.  The same groove it the outer frame helps to key the frame into the internal render.  Internal plastering in Zimbabwe uses a sand-cement mix, not the lightweight gypsum base coat that I was used to in the UK.  Again it has to do with climate and the economics of material production.

I'm going to break off there and post this.  I've been far too quiet this last 2 months, got to get something out there.  Part 2 will follow shortly.


Thursday, January 16, 2014


Christmas Eve and New Years Eve have come and gone.  I had a wonderful time in London the next 2 generations down.  Jack my grandson was 5 times older than the last time I saw him, walking around and getting into everything.

Back in Dubai, the local authority has announced a BIM initiative which has caused a bit of a stir.  We have renamed out local Revit User Group to Emirates BIM User Group (EBUG ?) and lots of chit chat going on.  One of our members wrote a short article which the magazine editor chose to title "Agents of Disruption".  Which sparked off a bit of discussion.

Is disruption a good or a bad thing ?  What about innovation, change, technology ?  Events like AU & RTC always include celebrations of the latest cutting edge gadgets, they're always looking to predict the "Next big thing".  I am not against this, just mildly suspicious.  As a species we have hurtled down the road of population increase and habitat modification at an alarming rate.  1000 years ago, more people and more technology seemed to be a desirable goal, not that people thought in those terms.

I'm just going to copy-paste a comment that I posted to "EBUG" this morning.  It conveys my attitude of "mild suspicion."

It's interesting how people latch on to "buzz words". The term "Disruptive Technology" is tossed around with gay abandon. Everyone wants to ride that wave. Shades of David & Goliath. But do we really want a world of continuous disruption, accelerating consumption, constantly changing value systems? 

Those at the forefront of BIM are talking about people being more important than software. Those resisting BIM are saying that we shouldn't abandon hundreds of years of experience. Perhaps they are saying the same thing from a different viewpoint. 

It seems to me that the "push it downstream" attitude is in many ways a relatively recent development. Forty years ago when we drew with pencils, we had to make decisions in a logical order. There was no undo button, no cut and paste solution for rehashing the design at the last minute. 

We should beware of thinking ourselves to be superior just because we are "early adopters". Let's not get drunk on the idea of grabbing "market share" by being the first in the queue. BIM will "succeed" if it becomes an inclusive way of working, accessible to all. Perhaps we should be focusing on continuity rather than disruption.

PS  For those who remember, the title refers to a rather strange song by Barry McGuire which dates from my mid-teens.