Creating History with BIM
A Crowdsourced Reconstruction of Sir Soane’s Bank of England
By Shaun Frazier, Paul F. Aubin, Jeff Mottle, and Lindsey DuBosar
Sir John Soane’s Bank of England, built from 1788 to 1833, was destroyed in the 1920s in what is considered by some architectural historians to be the greatest modern architectural travesty. Today, Soane’s Bank of England is revered by architects worldwide for its spectacular use of natural lighting and mesmerizing effects of scale, and inspires the neoclassical architectural approach of Robert A.M. Stern Architects (RAMSA).
Autodesk, HP, and NVIDIA joined forces with RAMSA, CASE, CG Architect, and Sir John Soane Museum to engage the world’s architects to help recreate Soane’s Bank of England in BIM, in the first crowdsourcing project of its kind. This article discusses the approach to modeling classical architecture with Revit, and how technologies from HP, NVIDIA, and Autodesk are enabling global BIM collaboration.
Modeling Classical Architecture in Revit
A big part of the challenge in creating models for Project Soane is creating the various classical architectural forms that are prevalent throughout this neoclassical facility. There are arches, vaults, pilasters, classical orders, lanterns and even caryatid columns! Modeling any of these elements has its own challenges and rewards. The challenge that I gravitated to was the creation of the Corinthian columns at Tivoli Corner.
The Tivoli Corinthian order is unique in many ways. It is clearly recognizable as a Corinthian order with its drum, abacus, and scrolling volutes at the corners supported by two rows of leaves beneath. However, the volutes are much more stylized than the typical (1). But in the center of the capital where there is usually some type of flower form sized about the same height as the abacus, at Tivoli the flower is nearly double the normal size and protrudes quite proud of the surrounding elements (2). Further, the top row of foliage which would normally spring from a cauliculus nestled between the inner and outer volutes (3), is also somewhat unique, doing away with the cauliculus and simply creating a third row of leaves in a more freeform configuration (4).
The columns at Tivoli Corner were modeled faithfully after the Temple of Vesta at Tivoli, which was Soane’s favorite building from antiquity.
I was able to locate a highly detailed plate with complete measurements of the Tivoli column in a book by J.M. Mauch. This book contains 100 plates with highly detailed illustrations of some of the most well-known surviving monuments from antiquity. Using this plate, I was able to apply the techniques explored in Renaissance Revit and apply them to the creation of the unique order matching the one that Soane used at the Bank of England.
Time and space here will not permit to share all of the steps in detail. However, I will outline the overall process that I followed and then do some detailed steps of the one of the leaves.
Overall Approach to Modeling a Classical Order in Revit
There are a few overall criteria that drive the entire creation process. These criteria were established in Renaissance Revit, but apply quite well to Project Soane as well. The first was the desire to create fully parametric families for each classical order. This means that the column should be able to flex to any required size and maintain all of its proportions when it scales. No easy task in the Revit family editor!
The other driving criteria recognizes the complexity and performance issues related to creating such complex families. The family should use three levels of detail including a very low detail schematic version for coarse that can be displayed in small scales and overall views. A medium detail version that contains enough detail to suggest the form and character of the order while still being lean enough to work at intermediate scales. And of course a fine level of detail that shows all of the detailed and organic geometry in full detail. This will naturally be the “heaviest” of the three and useful for close up views and highly detailed renders.
There are a few approaches to making families scalable in a parametric way. But the first thing to realize is that for most families, you have to build scaling into the family as a deliberate feature of the family. In other words, families do not scale by default. If you want a family to be able to have a flexible size, you have to define parameters such as length, width and height and then flex those parameters. If you want the scaling to occur proportionally, then you can use formulas to flex the parameters together. For example, you can make width and depth equal, or make one twice as big as the other. This way when one of them is flexed, the other flexes by whatever proportion the parameter’s formula dictates.
This approach works well for simple families that have few parameters. The coarse detail version of the Corinthian column uses a simple cylinder for its base, a tapered cylinder for its shaft and two simple forms: one blend and one extrusion for the capital.
In classical architecture, the diameter of the column measured at its base is the basis for all of the proportions. Mauch further breaks this down into modules (Base Diameter = 2 Modules) and Parts (1 Module = 30 Parts). All other dimensions of the order can be expressed in diameters, modules and parts. Therefore, this makes the formulas in the “Family Types” dialog simple expressions based on Parts.
There are other ways to scale family geometry. When working in the Conceptual Massing Environment (CME), you can build a “rig.” A rig is a construct created from reference lines; usually a simple rectangle or sometimes a 3D box. This rig will have dimensional parameters applied to it to make it flexible with just a few parameters. The geometry is built within this rig. It leverages reference points that are hosted to the reference lines of the rig. When the rig flexes, the hosted points (and any geometry driven by them) also flex and maintain their proportions. Building such a rig is conceptually different from other more common Revit modeling approaches, but offers a very powerful way to build complex forms without overly complex collections of formulas.
The final way to scale forms proportionally involves a workaround using a special feature of the Planting category. The Planting category has a built-in system parameter called height. This height parameter not only changes the height of the family, but actually resizes the entire family proportionally. However, to use this feature, you have nest two planting families together. I am not exactly sure why it takes two nested together, but it works! So the trick is, create a planting family. Set the height to the desired “starting” size. Build your geometry relative to this height. Then nest this family into another planting family. You can now use this family in another family or project. When you do, flexing the height parameter will resize the entire family proportionally! Exactly what we need in our highly detailed Corinthian capital.
Family Editor Environments
The coarse level of detail is naturally the simplest version. As noted above, it is created from simple extrusions and blends. These are built in the traditional family editor. The medium and fine versions require more complex geometry and leverage the freeform modeling tools available in CME. There are pros and cons of each environment. The main reason I went to the CME for the Corinthian order is to get smoother and more organic shapes to represent the leaves and other freeform shapes.
However, I did not build everything in the CME. The signature flower in the Tivoli capital is actually just a sweep and void extrusion in the traditional environment. The Abacus and bell, while modeled in the CME could have easily been modeled in the traditional environment. Even the leaves could be attempted there. And considering how angular they actually are at the Bank of England, you could easily argue that mine are too freeform and do not accurately capture the true form of the ones Soane used.
Andy Milburn, one of the top contributors on Project Soane, modeled a different version of the capitals and used the traditional environment.
Structure of the Capital
The capital is naturally the most complex piece of the entire family. To make things more manageable, the capital is broken down into several individual families. Each family is nested into the whole, positioned, rotated and copied as appropriate. Since most of the pieces is duplicated four or eight times, when an update is made, you reload the family and all instances update while maintaining their relative positions.
Abacus and Bell — This family is created in the CME. It uses a rig of reference lines to create the overall construct. The bell is a revolved form and sitting on top of it, the abacus is created from an extruded form with a swept void carving away the molding shape around the perimeter.
Short Leaf — This family contains two types in the medium detail version; one for the tall leaf and one for the short leaf. In the fine detail version, they are separated out into two separate families to simplify things. These families use a spline path to create the freeform shape of the leaf and then a series of points hosted along the path. The final form is lofted from the path and the profiles.
Tall Leaf — This family is saved from the short leaf and the parameters, path and profiles are adjusted to give the taller and slenderer form of the tall leaf.
Big Volute — In the Renaissance Revit version the small and big volutes are created in a single family. Both use a spline profile and several hosted points and profiles to create a lofted form. I kept the same basic family, but separated it into two families, one for each volute. The big volute uses the original family very closely. I varied the shape of the path, and the profiles to make them a bit more stylized and expressive. I also added more mass to them, particularly behind the spirals to make them appear more solid and substantial.
Small Volute — The Tivoli capital’s small inner volutes are very different than the ones at the corners. So I built these from scratch for this family. Here I used a simple spline path to create the loop form at the top. Then applied a simple round profile with an offset parameter. This allows the profile to shift and spiral outward.
Flouret — The flouret in the Tivoli column is really just another leaf. This is built similarly to the lower leaves, except there are two paths, they are drawn in different planes at an angle to each other and the profiles are loaded generic model families instead of being created in-situ with reference lines. Also, to make the forms a little more organic, the hosted points rotation parameters are leveraged to add a little twist to the leaf forms.
Flower — This family is created in the traditional environment. We certainly could build it in the CME and for the flower in Renaissance Revit, it is built in CME. So the choice is really up to you. I decided to give the traditional environment a try here and was satisfied with the results. The individual pedals and the bud are separate families. This just makes the copying and rotating a little easier. The pedals use a sweep, and this is cut with a void extrusion. The bud is just an array of pie-shaped sweeps.
Abacus Leaf — This family is back to CME, and is built just like the flouret family. A simple spline path with nested GM profiles.
The CME can give terrific results with nice freeform and organic looking geometry. To create an element, rather than a “Mass” be sure to start with the Generic Model (Adaptive) family template. It will create an adaptive component, which is another topic entirely, but for our purposes, this is what we must start with. Then go to Family Category and Parameters and change the category to what you need it to be. You can use Generic Model or if you want to use the planting scaling trick, use planting. Don’t forget to double nest. I then insert this into another family categorized as column.
Keep in mind that you can insert traditional families inside massing families, but not the other way around. So once you decide to use the CME, your final family will always be an adaptive component and a CME family.
Building organic geometry looks great, but these families get very large. This can be a detriment to project performance and is why it is so critical that you incorporate a coarse and medium version for smaller scales. This will help a lot when trying to load overall views. Save the fine detail for large scales and rendered views.
This is just one small part of Project Soane. Be sure to check out the awesome models created by the crowd and available for download at www.projectsoane.com.
Shaun Frazier specializes in assisting architectural organizations with integrating Building Information Modeling technologies into their design processes. He provides technical support, training, implementation, and consulting services around Revit Architecture, Rhino, and other architectural BIM solutions.
Paul F. Aubin is the author of many CAD and BIM book titles, including the widely acclaimed Renaissance Revit, the Aubin Academy titles, and dozens of Revit software video training titles for lynda.com. Paul is an independent architectural consultant who travels internationally to provide Revit software implementation, training, content creation, and support services.
Jeff Mottle is the founder of CGarchitect Digital Media Corporation (www.cgarchitect.com), the leading online magazine and user community for architectural visualization professionals. He also co-founded the CGschool, that caters exclusively to architectural visualization professionals. Having worked in the industry since 1996, Jeff has been involved in developing and speaking at conferences around the world.
Lindsey DuBosar has over nine years of experience in the architectural and building environments industry with a BS and M. Arch from Northeastern University. She has worked as a BIM consultant, designer, and job captain for several architectural firms in Hartford, Boston, and New York.
Learn more with the full class at AU online: Creating History with BIM: Crowdsourced Reconstruction of Sir Soane’s Bank of England.