Showing posts with label MT. Show all posts
Showing posts with label MT. Show all posts

From CAD to BIM: Part II - From CAD 2D to CAD 4D

The transition from 2D CAD to 4D CAD that changed the way architecture is nowadays.
Català - Castellano - Deutsch
Go to Part I

The Adoption of CAD software in Architecture firms was progressive, (I am still trying to find some information on a more or less exact timeline of CAD implementation in Architecture Firms) and it is nowadays widely spread in virtually all architectural firms. Some resisted the adoption of the CAD systems, and others have argued that CAD poses some challenges to creative design. Nevertheless, in 2009, the Architects Journal published the result of a study and poll amongst construction industry leaders, and the result showed CAD/CAM as the greatest advance in construction history.

Initially, CAD was used in Architecture Firms as a replacement for hand Drawing, meaning only 2D CAD was actually used regularly. This, was already an incredible step in terms of productivity, but it meant a less significant step in terms of work processes. Cad was in the beginning only a tool to draw faster. Until the adoption of 3D CAD, the proper change didn’t start.

Still, the initial use of 3D CAD was mostly as a presentation tool having not a very influencing role in the design process. Many companies still see it that way and only use 3D as a presentation tool. The truly significant change happened when 3D CAD started to be used a sa design tool. Its importance in the design process can be understood if one analyzes some of the latest building shapes and structure designed and built. Some of the latest buildings by Zaha Hadid, Frank Gehry, studio Morphosis, Asymptote and others, are hard to imagine before the advanced 3D CAD era. There are of course exceptions (complex shaped buildings entirely designed on the pre CAD era, one of my favorites is the Ronchamp Chapel by Le Corbusier) but you will agree with me that those complex shaped buildings have become much more common since 3D CAD has been adopted as a design tool.

Especially important on this late stage is the spread of complex surface modeling programs and explicit history and parametric capabilities. One of the big players on those two fields is Rhino with its explicit history plugin called Grasshopper. More and more buildings are being designed and the designs are being modified thanks to this sort of capabilities. The complex surface modeling features allows to model shapes and forms that would be impossible with simple 3D programs. The explicit history and parametric features allow the modification of these complex shapes without the need of remodeling them as it used to be common in primitive 3D CAD packages (and is still the common workflow in simple 3D CAD nowadays).

The 3rd dimension in CAD was conquered long ago and has been improved to the point that almost any imaginable shape can be modeled in a computer, and buildings can be built based on those 3D models. The 4th dimension (time) has been also explored with flythrough and animations being used in almost any big building project. But part of this 4th dimension of time can still be used more deeply. On the following documentary about the construction of the Yas Hotel by Asymptote in Abu Dhabi we can see this fourth dimension explored in depth.

Time is used not only for fly through animations, but to simulate the construction process and, that way, find possible collisions between building elements during the construction phase (the crane and some façade elements in the video). The logical step, is to use this 4D approach more and more to avoid conflicts during the construction phase.

What comes after the 4D dimension is the area where BIM means a real revolution. Incorporating the nD, or “n” dimension to the 3D Modell is what makes BIM so revolutionary and at the same time so necessary. We will explore this on the next issue of “From CAD to BIM”.
Go to Part I

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From CAD to BIM: Part I - History of CAD

A brief history of CAD to understand the path that led to BIM
Català - Castellano - Deutsch
I mentioned on a previous post my intention to go into BIM and IPD. Unfortunately for now, I have not the luck to be working on a daily basis with either, so my initial approach here will be more theoretical. I am trying to build the basis of what my Master Thesis is going to be, so forgive me if sometimes things sound a bit basic or repetitive.

BIM, as I see it, is still Computer Aided Design, but it allows you to add an “n” number of dimensions (like costs, scheduling, etc), and strongly modifies the work process to design, build and maintain a building. But since it is in my point of view an evolution of CAD, I think it is important to start with brief history of CAD.

In 1957, Dr. Patrick J. Hanratty had developed the first commercial CAM (Computer Aided Machining) program. It was a numerical control (NC) machining software developed in Pronto , the first NC commercial programming language. Hanratty is regarded as the father of CAD / CAM since these two branches became slowly one.

The first CAD software with a graphical interface was Sketchpad, developed in 1963 by Ivan Sutherland. Sketchpad was a Program in which the user could graphically interact with the program through a screen, a light pen used to draft, and a set of buttons that allowed the user to enter parameters and constraints. Although it never became commercially available, the ideas on Sutherland´s PhD dissertation became highly influential for future generation CAD developments.

First-generation CAD software systems were 2D drafting applications developed by a manufacturer's internal IT group and primarily intended to automate repetitive drafting tasks. During the 1960s, Hanratty himself developed DAC, a CAD system, while working for General Motors Research. Other companies like Ford (PDGS - 1967), McDonnell-Douglas (CADD - 1966), and many others followed soon after that.

During the 1970s the transformation from 2D to 3D began. The French Aerospace Company, Avions Marcel Dassault, developed CATIA, after purchasing a source code license from Lockheed Martin. CATIA is still nowadays leading software in the Aerospace, Automotive and Shipbuilding Industries. One of the most important research dissertations of the decade was K. Vesprille's (at Syracuse University) 1975 PhD dissertation "Computer-Aided Design Applications of the B-Spline Approximation Form" on Complex 3D Modeling. It is from the end of this decade that one of the first books marketing CAD for architects appeared. “Computer Aided Architectural Design” by William J. Mitchell from 1977 is a hint that CAD was already being marketed to architects. The widespread adoption by architects would take still years.

During the 1980s the CATIA, Pro/Engineer, Unigraphics and I-DEA became the leading CAD software packages. All of them powerful 3D modeling software systems with their core business on the industrial production (for this reason sometimes referred as CAE systems rather than CAD) and their main hardware platform being UNIX. On the 2D and PC Platform Autodesk, with AutoCAD, was gaining market share.

It was on the 1990s, that the PC explosion happened and with it the raise of a new player. Autodesk had been focusing on the PC platform since its AutoCAD version 1 released in 1982. The licensing of the ACIS 3D Kernel, allowed Autodesk to release in 1993 AutoCAD Release 13. For the first time AutoCAD had 3D Solid Modeling Functions. AutoCAD became widely spread, but other packages like Bentley’s Microstation, soon became strong competitors on the mid-price market. The widespread adoption of CAD by architectural offices was happening slowly and soon would burst into being the dominant trend. We will see more on that on the next post on this series

Sources: CADAZZ, American Machinist

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