Paper Models, II


Because she is awesome, my wife got me an awesome birthday present: an E-Craft electronic die cutting machine.  The target application of this tool is scrap booking, and the machine’s marketing boasts that it can cut sheet magnets and glitter paper, AND it comes in pink and periwinkle blue.  None of these features seem to scream Architecture, Engineering, or Construction.  Our (AEC) people seem to favor the white, the black, tiny glasses, and bowties.  And NO GLITTER. 

Our people are, of course, no fun. 

So what IS an electronic die cutting machine?  Similar to a pen plotter with a knife blade, I’m using it like a poor man’s laser cutter.  You feed it an SVG file, and it will cut whatever the hell it is, out of whatever you feed in the front (thin stuff, within limits).  You certainly can’t build ANYTHING, it isn’t a 3d printer.  But it’s actually more interesting, IMHO, because it forces you to build certain KINDS of geometry.  Stuff that can be folded, bent, creased perforated, poked, scored, and cut out of flat material. 

(Hmm . . . does that sound like a reasonable limitation for lots of kinds of architectural construction?)

For today’s exercise, I will construct Sir Norman Foster’s toroidal masterpiece, the Copenhagen Zoo Elephant House.  Because the universe demands symmetry, I will cut it out of a donut box.


The workflow to get the cut pieces involves Vasari (or Revit, which needs the STL Exporter addin), the open source vector art editor Inkscape (and a plugin extension from Evil Mad Scientist’s Eggbot), the papercraft application Pepakura, and a papercutter (this can be scissors, a lasercutter, an intern, or the Ecraft tool I’m using.)  Pepakura will run you 38 bucks (totally worth it), the rest are free.

Step 1: Rational Forms in Vasari/Revit


While there are some more exotic methods to create flattenable forms (see this, and this), I’ll start with the method Sir Norman often uses of dicing up rational primitives.  For the details on this process, check out this post.

Step 2:  Panelization in Vasari/Revit

Once the surface has been divide, populate the divided surface with a simple surface.  That is, make a new curtain panel with just one surface and load it in.



More details on this part can be found here.

Step 3: Export to Pepakura and Unfold


Once I have my panelized form, I isolate the pieces I want (either using temporary hide/isolate or visibility graphics) and export using STL export (either native to Vasari in the add-ins tab, or as a plug in for Revit).  For this kind of form, I like to also send out the “floor” of the form even if I’m only interested in the roof, as it helps keep the roof shell from spreading out.

Import the file into Pepakura

Again, more details on this process can be found here.

Once I get the panels into Pepakura, I just hit “unfold” and get the geometry needed for cutting. There are lots of little bitty edge pieces that I just throw out, but otherwise, I’m good to go.   For this kind of form, I also like to turn OFF the default behavior to make “tabs” as they just get in the way.


Step 4:  Convert to Ecraft file in Inkscape

My cutting machine only takes SVG files, and Pepakura doesn’t make ‘em, so I need to do some data wrangling.  I output to EMF, which is a vector format, and open it up in the open source vector art editor Inkscape.

While I’m in Inkscape, I like to use the a little tool provided by Evil Mad Scientist for their Eggbot printer called Reorder Paths for Speed.  What this little delight does is take your jumble of lines and puts them in order using a traveling salesman algorithm.  If you don’t use this, your cutter will jump all over the place drawing lines in the order they were created.  Using this plug in makes the cut time way more efficient.


(If your shape is relatively simple, and you have Autocad, you can use the “boundary” command to recreate the shape, which has the result of making the cutting process continuous rather than skipping around.  But as far as I know, Autocad doesn’t make SVG files)

Step 5: Cut and Fold

Now we are ready to save to an SVG file and import into the E-craft software. 


The capabilities of this layout tool are pretty limited, so you really need to be ready to go before importing your SVG.

Before printing, I need to trim up my donut box a bit


And we’re off!


Pop out the pieces



Assemble with many little pieces of tape


Make it out of watercolor paper instead of a donut box and you can bring it to a client meeting!  I have found frozen pizza boxes to be one of the most reliable materials.

This description was fast and dirty, so apologies if run into any snags on the the way. As with any toolset, each one has its own personality and quirks.  Pepakura and Inkscape are both really powerful and interesting in their own right and deserve deep investigation.  The Ecraft is a crazy machine that is often as frustrating as it is excellent.  Maybe I’ll do a post on how I MacGyvered the thing to use real pens.



API-Yi-Yi: Boost Your BIM


For all y’all out there looking for more information on expanding your out-of-the-box Revit experience, there is a new blog with tips and tricks for using the API.

Boostyourbim was started up less than a month ago by my friend Harry Mattison, who brought you such greats as the parametervalues from image data addin.  So why should you rely on him for information on the Revit API?  He helped build it!


Pattern Deformation


A big shout out and thanks to the folks at DesignCoding, “a digital diary of research on the relationship between basics of geometry and design computing”.  They’ve always got nice stuff going on with that site.  I was looking at their post on Parquet deformations and had the familiar “oh yeah! Lemme try THAT!” response

As with many things that look complex and awesome, the underlying logic is pretty simple.  Here we start with a regular square grid of a divided surface.


Onto it I place a 5 point adaptive component that is structured like the image below:


With a model line between points 2 and 4, and another line between 5 and the midpoint of 2,4.  A reporting parameter between 1 and 2 drives the point p1 hosted on the line between 5 and midpoint 2,4.

Four placement points are hosted on the nodes (2, 3, 4, and5), and another goes on a point off to the side, hosted on a free point.  This point (1) serves to tell the family how far it is from a starting point


Using a reactor type of behavior, as the point 1 gets further and further away, it drives p1 in the family.


This basic idea can then be amplified with a slightly different AC, placed in a sub pattern:


This family is placed four times, in a radial arrangement, with point 2 at the middle.



Repeating this block of 4 components results in 4 separate Repeaters, which resolve into this pattern:


Pattern Deformation

Download the files from here


Tool Making: Way better Bezier-ish by Points

As previously discussed, Revit/Vasari has a couple kinds of splines  (regular spline and spline-by-points) that  you’d think  they were pretty similar (but you’d be wrong).  I made some tools to improve on this situation using Adaptive Components, but have refined this method.  This image shows 3, 4, and 5 point spline-by-point curves inside of an adaptive component rig, superimposed on a regular control polygon spline to illustrate the divergence (There’s not much difference, but double click to take a closer look). 
It uses the same methods as shown in this post but does further subdivisions of the control polygons for greater accuracy and flexibility.

A couple of things I noticed.  Most significant, the tangency conditions at the start and end are very close approximations. 99 times out of 100, this should be fine.  Here is an example of when it falls down:
On the left, two real b-splines drawn coming to tangency conditions.  On the right, the 4 point adaptive component spline by point family. 
Because the curves come together into a near tangent, but not quite, they slightly overlap.  It isn’t visible even zoomed WAY in.
But the result is that you can’t create a form element from the fake b-splines, because it will create a self intersecting form, but the real b-splines can.

[Clarification:  This failure is kind of hard to reproduce, it doesn’t happen for all situations even like the one shown,  there is a similar geometry in the sample files, and it works perfectly.  I think it has to be of a particular really huge scale.  In general, you can use this to make forms just fine, as shown in this post.  Here is an exaggerated view of what is happening the joint between the 2 curves at a bazillion times magnification:


Again, I have a hard time reproducing this problem, but it can be done.  If you’re worried about it, experiment a little. ]

The other issue that is a bit more obscure,  is the four point 4 spline doesn’t create a proper cusp when you do a crossed rectangle (shown here, a rectangle with points going 1, 3,2,4 in clockwise order) as a real bezier does.  Rather, it makes a bump. 
Details, details.

Download the families from here.


Autodesk University 2012


November has been hectic, but I promise I will be back in December with more advice on things you didn’t know you were interested in.

In the meantime, if you are in Las Vegas this week, I’ll be co-presenting a couple sessions at AU.

AB3910-L - Coding Autodesk® Vasari: Scripting for Conceptual Design

Nathan Miller , CASE Inc
Zach Kron , Autodesk
Matt Jezyk , Autodesk, Inc.

This hands-on lab will introduce participants to the fundamentals of Python scripting and visual programming within the Autodesk Vasari conceptual design environment. Custom code gives users the ability to efficiently automate many design tasks while also enabling new generative design capabilities. This lab will demonstrate how to compose useful Python scripts with the RevitPythonShell add-in and Dynamo Visual Programming for Autodesk® Revit® software and Autodesk Vasari. The lab will provide users with resources and step-by-step examples for automating geometry creation, adjusting family parameters using external data, and sharing information with different design platforms.

Additional Information
Wednesday, Nov 28, 8:00 AM - 9:30 AM– Mandalay Bay H, Level 2
Key Learning Objective 1: Explain the basics of Python scripting in the Autodesk Vasari design environment
Key Learning Objective 2: Automate conceptual form creation
Key Learning Objective 3: Drive family parameters programmatically
Key Learning Objective 4: Take advantage of external data to create geometry and drive parameters
Professional Credit:AIA Approved
Class Type:Hands-on Lab
Class Length:1h 30m

AB2410 - Echo Chamber: Complex Parametric Arrays in Autodesk® Revit®

Andreas Dieckmann , RWTH Aachen University
Zach Kron , Autodesk

To a large extent, buildings consist of repetitions of identical or sufficiently similar elements. In its previous versions, Autodesk Revit software already included a number of tools that allow for repeating elements, albeit with some geometric or category-specific limitations, such as arrays, divided surfaces. The new Divide & Repeat workflow of Autodesk Revit 2013 offers a more open and versatile functionality that can be used in a host of different contexts. This class discusses various patterns for creating Divide & Repeat rigs consisting of a combination of reference points, divided paths, and divided surfaces. We will take a detailed look at each pattern and its practical application in architectural design by examining examples of iconic buildings and identifying how certain aspects of those buildings could be created with the Divide & Repeat functionality. The class also touches on the methodological implications of creating rigs and components for the discussed patterns.

Additional Information

Tuesday, Nov 27, 3:30 PM - 5:00 PM– Palm D, Level 3
Key Learning Objective 1: Identify repetition strategies based on design intent
Key Learning Objective 2: Devise rigs for Divide & Repeat based on repetition strategy
Key Learning Objective 3: Devise repeater components based on repetition strategy
Key Learning Objective 4: Explain repetition in the context of case studies of iconic existing buildings
Professional Credit:AIA Approved
Class Type:Lecture
Class Length:1h 30m


Happy Halloween IV

p4 (2)

[John Fout’s pumpkin attacking a coworker’s structure]

Good evening, and welcome to the 4th Annual Parametric Pumpkin Carving!  In some cultures, the number four is bad luck, as it sounds like the word for DEATH.  Tetraphobia, as it is called, is entirely appropriate tonight, as you will see . . .

Behold!  [and download]

The assembled might of multiple digital media!  Their powers magnified and catalyzed by the churning, chaotic cauldron of All Hallows Eve

Look upon them, dear readers . . . if you dare . . . 

Baddest:  Ritchie Jackson

Following in the tradition of badasses, base jumpers, Baumgartners, and Nikola Tesla, “Bad” in this case is regarded as high praise for an uncanny scariness, a serious and terrifying aspect.


First time Parametric Pumpkin winner Ritchie Jackson was not satisfied with taking home the gold last year for Mostest Parametric.    In fact, it whipped him into a fighting fury.  He established an island lair in the mid-Atlantic, whence he was able to monitor and brood, creating the Honourable Society of Cucurbita Carvers and building the ultimate weapon of pumpkin distribution, the Fabrica Cucurbita.

That, I would assert, clinches a person’s right to the title of Pumpkin Badass.  But keep in mind that it is done, as many badass enterprises are, for the good of the community.

2012-10-31_1407Now, you too, dear reader, can experience the raw Power of the Pumpkin with Fabrica Cucurbita, a first person shooter, immersive pumpkin gaming experience.  Just download and uncompress the zip file, fire up the exe and you’re off defending the cause of pumpkin carvers everywhere.


“All the geometry was done in that king of 3d apps - Sketchup (free version) - but don't tell anyone as it will ruin my reputation. Come to think of it, working on pumpkins has probably damaged my reputation anyway so go ahead, let the Revit/Vasari maestros have a hearty laugh at my expense!”

[See!?!? Total badass.  Just throw a “Mwahahahaha!” in there.]

“Whilst none of the geometry has been generated by code there is a lot of scripting behind the scenes for the various interactions and the graphics for the scanner particles and electrical arcs on the pumpkin gun.”


“But wait” you, the reader, say. “You haven’t even shown any of Ritchie’s pumpkins!”  True.  I’ve already given too much away, the beauty of games is in the manner in which they reveal themselves.  Suffice to say, Ritchie has a badass cannon, and he’s not afraid to let you borrow it.  Download it, use it.  Heck, be a badass yourself and try it out during that conference call you have later today.


The Goodest:  Andy Milburn

The pumpkin that gets to the wholesome essence of both Jack O' Lanterns and the design platform on which it was built.  Free of workarounds and hacks, this winner is a model of both creativity and good citizenship.


Like Steve Martin, Frank Zappa, and Bertolt Brecht, Andy Milburn finds the profound aspects of life in small, comic, and ridiculous things. For this I am grateful, and I’m not kidding.

Our second repeat winner this year, Andy has set up a bit of an artisanal digital fruits and vegetables green grocers shop out in the deserts of the UAE.  You may have already seen some of his work, as he has been developing this masterpiece of parametric vegetation for the last 2 weeks, out in the open, at Shades of Grey.

2012-10-31_2327It’s difficult to summarize what Andy has done.  Like last year, he has taken the idea of making digital pumpkins to a whole new level.  Exploring issues of proportion, pattern, color, composition, and more.  Andy draws inspiration not only from the pumpkin, but Disney, Habsburgian painters, and basically the entire vegetable kingdom. 


Seeing Andy at work is humbling.  Last year, when I started reading the 6 part epic, I was struck by how beautifully he had captured the idea that, in this somewhat frivolous exercise of carving, there was the kernel of ideas that are so large and profound.  This year, he built on top of the somewhat abstract ideas, and actual demonstrates how to put them into formal expression, over and over again with various challenging shapes


There are so many lessons and wrinkles in the story leading to these images and files, that I insist that you go and read all 9 posts right now.  Then, Andy is going to give a little walk through on Vasari Talk next week.  You can and should register to get in on this talk from here.  Space is limited, so do it now, takes a minute and costs nothing.


Mostest Parametric: David Wood

The pumpkin that is shaped by rules and variables, that is definite yet infinitely flexible.  It not only defines a particular look and feel, but conveys the possibility of endless variation.


This award is always a little tricky, as it is not necessarily concerned with what a pumpkin is, but what it could beDavid Wood submitted a very humble piece of geometry (above) and a Dynamo definition for it:


From this, was able to make these shapes by adjusting the parameters:


In David’s words

“I based it on Johan Gielis’ Superformula of an ellipse, from his 2003 paper, with the parameters set to generate a sort-of pumpkiny shape. You could tweak the parameters to create all manner of non-pumpkiny shapes if that was your thing.
Anyhow, other than the fact that it’s very slow; and very fragile; and only runs in debug mode (so far); and that if you change certain parameters, it breaks the loft, the Dynamo diagrams do eventually pull together to make parametric pumpkins! A triumph.
How it works:
The core is the ‘Superformula’ node, which calculates one value. This is used by the ‘Superformula XYZ’ node to generate an XYZ, and then the ‘Superformula Loop’ node generates a loop of lines.
The ‘Superformula Loop Driver 2’ node generates a loop at a particular polar coordinate, so that the main workspace ‘Revitator’s Punkinator’ can generate a series of loops like horizontal slices through the pumpkin.
There are a bunch of other helper nodes like the x^y node, that fill in specific functionalities in Dynamo. I believe that I’ve included them all in the zip, but shout if there are any missing.
I’ll post some more detailed explanations & screenshots on the blog over the next week or so.”

A couple other things of note.  I found that it only runs on a Revit installation of Dynamo, not Vasari, and it gets slower the more you play with it.  Yay Alpha software!

Please keep an eye on David’s Revitator blog, great things are coming.

Special shout outs and appreciations

John Fout

John had a kickass pumpkin this year.  Here it is eating a structural system.


And in full tendrally attack mode.

John Fout’s Attack Pumpkin

It kills me, John, but your badass veggie was up against a first person shooter game this year.

Kelvin Tam


Kelvin’s wicked Pumpkiron Man has various curvaceous sliders that can create some great variations.  He also demonstrates some tricks with loaded profiles that I had no idea about. 

“What I have done is nesting a profile family into a new family, make points exactly at the same locations of the points in the nested family, select the points and do splines.  In this way when the secondary profile family is loaded, all the model lines are picked altogether since they are no other reference lines from that family.”

Might seem a little obscure, but this method opens up a lot of possibilities for using loaded profiles.  For more on this kind of work, read this.

Paul Aubin

Paul took his existing research with classical columns and plugged pumpkins into the proportional systems.


Voila!  New wine in old wineskins!

Alfredo Medina

Alfredo’s haunted pumpkins have excellent spring


Try them out with the Sliders plugin.

Scott Dietz

Scott had a late arriving set of images that are tantalizing!


Send in those rfa files!  I’m very curious about how this was put together.


I am out of time, but thank you thank you thank you all who sent in the wonderful, fantastical and ridiculous pumpkins. 

And apologies for the overheated prose.  My son and I have been reading a LOT of 80s era comics . . . they were not only more vavavoomy back then, but also surprisingly chatty.