Monday, April 25, 2016

WAITING ROOM BLUES

Project Soane has been woefully neglected so far this year.  I had hoped to keep my momentum going, but it hasn't quite worked out that way.  Not enough hours in the day, or days in the week.  But I have managed to put in a little work over the past 2 weekends, tackling the North West extension that completed the territorial expansion of the bank.



The new build of the NW Extension is colour coded green.  The Pink areas towards the bottom left are parts of the building that predate Soane.  And bottom right, outlined in cyan is the corner of the NE Extension , basically the original junction between Princes Street and Lothbury.  One result of the NW Extension is that Princes St gets straightened out so that it meets Lothbury further along at Tivoli Corner.  The Lothbury facade gets doubled up, mirrored about a hinge point indicated by the asterisk here.



The mirrored copy of the Bullion Gate becomes the soldiers gate (small arrow to the right) which gives access to the Barracks (B)  This is down at the lower level.  Above the barracks are new printing works, fitted into the angle behind Tivoli Corner and arranged around the Printing Court (PC).  This court is closed off to the south by the new Accountants Office (A), a rather grand space with large Ionic columns and a shallow barrel vaulted ceiling.



Top middle is the new VIP entrance, leading into the Doric Vestibule, and a long passage that eventually takes a dog-leg to the right.  Eventually another right turn takes you to some waiting rooms in the old part of the bank, and a new Governor's suite.  The governor's new office faces into Waiting Room Court (WRC) so that he can watch visitors as they start their journey down the long passage, accompanied by one of the pink-coated beadles.



This is a classic piece of Soane originality.  The passage is open to the court on one side, framed into bays by pairs of highly abstracted giant pilasters.  He explored several more conventional treatments before hitting on this solution.  This is typical of Soane.  He did the same thing with Tivoli Corner, trying out all kinds of treatments before the problem settled down in his head and he achieved the clarity of vision he was seeking.



The stern Greek formality of the Waiting Room Court contrasts sharply with the much more homely, brick arches used in the Printing Court.  Here Soane adopts his standard "low-rental" mode, as you would expect in a back-of-house area.  The image below is far from complete, but it gives an indication of the difference in feeling.



When I work on this kind of project, exploring a historical period or a vernacular style, I find that many of the same issues come up as when working on a fee-earning job in an architectural office, but the difference in context is informative.  In that sense it becomes a very useful learning experience, quite apart from its intrinsic value.



For example there is the whole question of how to quickly sketch things out using a tool like Revit.  In this case I started out by representing the various openings as simple voids cut out of the walls.  These can easily be parametric families because of the simplicity of the shapes, so it's possible to "feel your way" to the correct size and proportions if that information is not readily available as legible dimensions on the drawings.



This is exactly how Soane set about tackling the same problem.  Most of the "design development" drawings in his archives show windows and doors as black holes.  It can be quite frustrating at times, because you often have quite a detailed understanding of a particular facade, except for the design of the doors (unless you happen to stumble across and old photo)  The image above shows 5 versions of the open side of the long passage as it passes by the Waiting Room Court.  I have lined them up as an evolutionary sequence culminating with something very close to the implemented design.  How I wish that I could eavesdrop on a day in his office when he was debating with his pupils the pros and cons of these five schemes.  Notice how the idea of expressing the 3 central bays starts off in the basement and gradually spreads through all 3 stories.  See also how the idea of a super-flat pediment creeps in half way and then gets rejected.  Ultimately that was to re-emerge atop the attic feature that crowns the central bay (much smaller of course)



The next stage in my "design process" typically involves building non-parametric families for the sizes that I have established in stage 1. My second stage, "fleshed out" families for the arched windows use extrusions for the glazing bars.   These are modelled directly in the family (no nested components) and each extrusion contains perhaps 30 line segments.



So this would quickly break if you tried to flex the family, as you can see in the next image, which also illustrates the "trace-over" method.  I'm using images from the archive, dragged into family editor, scaling them to match the size deduced in stage 1 and cross-checking against any stated dimensions in the archive drawings.  This snapshot image is also the source of my assertion that Printing Court is predominantly face-brick whereas photos of Waiting Room Court show it to be Portland Stone just like the rest of the Bank. 



We are getting to a 3-stage process of family development in order to accommodate the demands of a rapidly evolving design, or in this case a rapidly evolving "understanding" of whatever it is that I am studying with my BIM pencil.  Stage 1: highly abstracted, parametric families.  Stage 2: directly modelled, highly specific families.  Stage 3: more detailed parametric families. 



In this case, the third generation families use nested components for the sliding sashes, and a series of sweeps for the glazing bars, in place of a single extrusion.  The sweeps have two advantages.  They are easy to lock to reference planes, and you can start with a simple rectangular profile, knowing that it's easy to elaborate this later on.  The first image shows me locking the end of a "path sketch" to a reference plane, and you can also see the angled reference LINES whose ends are locked to the centre point of the arch, and to which radial glazing bars are locked.
Just in passing, here is my rig for controlling the centre point as the width and height vary.



By the way, I typically make one sweep, copy this around and edit it, rather than starting from scratch with the sweep command.  This saves me the effort of repeatedly assigning a profile, subcategory and material parameter.  I guess there are other ways to approach this.



Controlling the end points of these radial elements is quite tricky.  I opted to use a detail component which is rendered invisible in the project environment by unchecking the box.  Looking back at this I can't quite understand why I used straight lines when circles would have been simpler. (plus more adaptable should the angle change)  Anyway you just lock the detail item to the centre point and link its parameters up to the width parameter via simple formulas.



I tackled the sliding sash window in an earlier post from a rather different angle: direct modelling of the way this technology works, in some detail.  More than 2 years ago, and I said then that I hoped to explore how I would make a family for this kind of window that could be flexed, and used in a real project.

sash windows post

So it was very interesting to come back and take a stab at developing a parametric version.  The level of detail has to be lower of course, so what is realistic for a project that might contain dozens of instances ?  That's always an intriguing question.



This brings up an interesting issue which I will use to conclude this post.  What is the relationship (if any) between a detailed model of a typical item like this, and the simplified version (family) that is placed in a project.  It seems inherently "UN-BIM" to model these completely separately.  But how would we build digital links so that they are both kept in sync, automatically. 



The current paradigm for fine detailing is to draft over a callout view in 2d.  Now that's fair enough in many cases, but sometimes it really would be beneficial to develop a detail in 3 dimensions.  It seems to me that one of the fundamental challenges as we move forwards with BIM is how to automate the synchronisation of design as we jump up and down the scale from "cupboard detail" to "typical hotel room" to "400 key hotel" to "urban district" and beyond.



More on the continuing saga of Project Soane very soon.




Saturday, April 2, 2016

EDGE FREE SHARING

OK so I've been updating my Fritz Hansen furniture collection.  First of all they are great designs, secondly there are really good downloads available from their website, both 3d and 2d, and finally the stuff I did a couple of years ago has been a very popular download.

Last time I showed the Oxford chair by Arne Jacobsen.  Their are multiple versions of this: two styles of base, 3 heights of back, with and without arms = 12 permutations.  So I separated out the components, made them into nested families and used visibility switches to create the types.  Actually I made 6 types and used an instance parameter for arms/no arms.  One strange thing.  There were some leftover edges despite the processing in 3d max.



I decided to push the CAD import bak into Max for further edge hiding.  Actually this is the only thing I've ever learnt to do with Max, so don't be intimidated. If I can learn do it, so can you.  With a bit of trial and error I was able to select the remaining edges and render them invisible also.  Practice makes perfect.

You can see this clearly in the next image.  I started with the low back, then progressed to the medium and high back versions.  See how much cleaner they are.



Eventually I did go back and clean up the low-back chair.  A side view of this isolated component illustrates the subtle irregularities of the mesh geometry in the downloads.  For some purposes this will be totally unnecessary, but if you need a high resolution render that captures the qualities of natural leather ...



Next I tackled the Alphabet range, a modular set of roughly rectangular sofa elements that can be assembled in a variety of ways.  Here the value of the irregular mesh in capturing the soft and floppy leather effect is much more obvious.



And now I'm totally hooked, so I tackled a couple of designs by Poul Kjaerholm: the PK31 armchair and PK24 lounger.  I don't know about you, but I haven't seen shaded views of Revit furniture families that look as convincingly natural as this before, and it's something I've been working on for several years now.



The collection is growing steadily as you can see: the egg, swan, space, Rin, Favn ... all looking so clean and comfortable.  And by the way, most of these families are coming in at 600 to 800kb.  Even the Oxford, with 12 different permutations nested into one family weighs in around 1300.



I'm going to share this, but please remember that it's a work in progress.  Some of the families have 2d symbolics in plan and elevation.  Others haven't yet progressed that far. It may be worthwhile setting up a switch to turn off the 2d graphics in case you prefer the shaded look.  I wish there was a way to do this selectively on a "per view" basis, but I can't think of one ... except for the coarse/medium/fine method.
 


Also, maybe there should be a coarse version of the geometry, much simplified.  Right now I have everything switched off in 3d views at coarse scale.  For example these are the visibility settings for the Alphabet range.  I have masking regions and detail lines in plan views only.  Maybe I will add symbolics to elevations later, certainly you get crisper lines that way.



So that's all for now.  You can download the work-in-progress collection file from here.


FRITZ HANSEN COLLECTION

ALTERNATIVE LINK



Thursday, March 31, 2016

BE GONE SHARP EDGES

In the previous post I made an appeal for anyone who knew how to hide polygon edges to shout up.  Many thanks to Fred and Arthur for the very rapid response.  Seems I should have done a web search :)  Anyway, there is a nice video here      LINK        and a written description here    LINK.

I'm a complete novice when it comes to 3d Max, but I managed to work this one out and created a couple of plumbing families from some Bagno CAD files I had downloaded.  I was quite pleased with this and talked to two of our visualisers for a couple of extra tips on the interface before tackling some Fritz Hansen furniture.



I posted about this long back, but at that stage I was stuck with the mesh edges.  LINK.  So let me take you through the process with a conference chair range called Oxford.
Drag the CAD file in (import) and place it.  Set the Visual Style to Clay (my preference, you can see the geometry clearly).  Click on the little modify symbol (top right, like a rainbow in a box) It should say "Editable Mesh" in the box below.  Then click on the open red triangle in the next box down (Edge)  Now you are selecting edges so put a window around everything.



Next scroll down to the bottom of this panel and click on "Invisible" Nothing seems to happen, but if you now change to wireframe the edges will ghost out.  Click on empty space to deselect and they disappear altogether, so go back to "clay" so you can see the faces and select objects.



Scroll the panel back up, and click on the box (Element) at the far right under "Selection".  Now you can select sub-elements.  In this case I have selected the five-legged base. Then click on "Detach" to make this a separate object. You don't have to give it a name because we aren't saving the 3d Max file, just exporting to CAD. Just accept the default naming (Object 001 etc) Continue like that to break up the chair into separate pieces.



This will allow us to place the base and the seat itself on separate layers.  Also we can delete the cylinder if we want, and replace it with a native Revit extrusion.  That might be better than a facetted mesh.

Finally we will export as a DXF 2004.  Don't know why that is important but apparently it is.



Opening this up in AutoCAD, everything is on layer 0. I'm going to make a new layer called "_Fabric" and place the seat on that.  Then I put everything else on a layer called "_Metal"  Save as DWG. I don't think the version matters this time.  (by the way, I checked that everything was set to "bylayer")



Now let's try bringing this into Revit.  Start a new family from the Furniture template and import the DWG. In this case it seems the base units are Centimetres.  Sounds right for continental Europe. I had to nudge it into position over the origin.



Looking at object styles both line colour and Material are coming from the layer colours I set up in Autocad.  I'm going to delete the two surplus layers (0 and ASHADE) then change the Line colours to black.  Also I substituted default materials for the automatically generated ones (Render Material 0-0-255 etc) and deleted all these in the materials browser. Don't want to transfer a lot of junk into my projects.



Now this is a fairly useable family as it is, but ultimately I will probably separate out the various elements.  The seat comes in different heights, and there are also different styles of base.  (one with wheels)  So it makes sense to follow a modular approach and mix and match nested components.  Also I'm going to substitute native geometry where I can, for a cleaner look ... basically the cylinders I think.  I think it will also be valuable to use 2d drafting in plans and elevations.  Better for performance, but also a cleaner graphic look for orthographic views.



This particular family is not the most dramatic demonstration of the technique perhaps.  You could almost do this in native geometry entirely.  You wouldn't get the subtle double curvature and rounding of the edges but it wouldn't be too bad.  But earlier on I did the Rin chair which is a complete non-starter with Revit's modelling tools.  This turned out very nicely, and looks quite good in plan and elevation even without 2d drafting elements.



Looking at Revit Forum, one comment caught my attention: "... use only if absolutely necessary. Make Native Revit geometry if possible."   Now I do agree with this, but words like "necessary" and "possible" are open to interpretation, and I am aware that some members of the "expert elite" are more dogmatic on this issue than I am.  I think that an acceptable version of the Oxford chair could probably be made as Native Geometry.  It might look a little stiff in rendered views compared to the subtle curvature of the mesh version, especially around the edges, but for most purposes it would be fine.  The Rin chair conversely is a clear case where adapting the downloaded mesh version is really a no-brainer.  In between there are many shades of grey.  Ultimately it's a judgement call.

I will be doing more of this type of work, and probably sharing the families, but for now, I'll finish with a shot of 3 of my new "edge-free" families nestled among older messy-mesh versions from my previous Fritz Hansen post.   Furniture Fritz

Needless to say, I'm quite excited by the possibilities.