B-2 - Dung T.

This blog post starts with my expression about next topic discussed throughout this week. I believe BIM would become an integral part for my future career, as many of BIM applications have been subscripted by AEC firms recently. Moreover, at my first Co-Op with the city, we had to delay our construction process when a design change was accepted. In fact, if a BIM model of the pipe connection was created, construction could seamlessly continue instead of waiting for 2-weeks due to re-investigating and re-evaluating of the old design. However, I have neither experience nor knowledge about BIM before enrolling in the class, which has haunted me since transferring to Drexel. My blog post may contain ambiguous statements, and I am waiting for our lecture next Tuesday for discussion about BIM.

The first part of Chapter 2: “BIM Design Tools and Parametric Modeling” discussed about the development of object-based parametric modeling. Several researches were conducted to generate three-dimensional model during 1960s. After the introduction of solid modeling in 1973, two modelling techniques has been competed for years: Boundary representation (B-rep) approach and Constructive Solid Geometry (CSG) approach. The first technique developed an object through operations and object arguments, when the second one applied algebraic expressions to define object. Contemporary parametric modeling has been established after the combination of both techniques, as the CSG-like tool acts as a database to create a visual model in the B-rep tool. Frankly, although it is boring to read, the development of object-based parametric modeling established a solid foundation for further techniques that could not be applied until computing power would handle highly complex models.

The development of object-based parametric modeling tools inspired basic capillaries of BIM design applications, which can currently handle more capabilities than a basic 3-D object designing tool (as SketchUp). By involving with different uses, BIM design applications must split into three distinct way to describe: a tool, a platform, and an environment. For instances, BIM environment applications can utilize tools within the application for crafting and managing design database (In other terms, “libraries of objects”). Moreover, most BIM platforms can perform other engineering or management tasks such as structural analysis, energy analysis, rendering, and cost estimating, etc.… through add-ons interfaces. In short, BIM provides a faster, more precise, and affordable option to design, build, and manage a project.

Revit platform was introduced as current market leader for BIM in architectural design by the authors. It is still a best-known BIM platform in the building construction, since Revit has been listed as either required or recommended skills for design jobs. Being an Autodesk product, Revit users can access to Autodesk-provided library (SEEK) for object specification. Also, many vendors create libraries of their products for Revit platform, which supports a big list of file types: RVA, DWG, DWF, DGN, GSM, SKP, IES... Moreover, due to its dominant market position, many add-ons and softwares in diverse sector under civil engineering umbrella have been associated with Revit including structural (STAAD), mechanical (MagiCAD), energy (EnergyPlus), rendering (3D Max), facility management, site analysis (Civil 3D). However, it can only process smoothly for projects lower than 300 MB, and provides limited support for complex structures.

Source:

C.M. Eastman. "Chapter 2: BIM Design Tools and Parametric Modeling" in BIM Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers, Engineers, and Contractors, 2nd ed., Hoboken, NJ: Wiley, 2012 pp.31-97.

Comments:

Kerry, 

Thank you for summarizing the long chapter into 3 paragraphs, which I was used as a guideline to skim through 66 pages of dry writing. I believe Revit has changed drastically than at the time this book was published, and additional options have been added. Similar to Zac comments from above, it is essential for a large multisector company to open a BIM-related modeling department to fully understand about the software as well as the technology

Dee Dee,

Thank you for sharing your Co-Op and Revit experience at your blog post. I really wonder about the central model function of Revit. It is really cool to design models of structural system or MEP system without depending on Architect's model. Also, I am curious what would happen if the architect decide to change a design? Otherwise, it is really cool to know that Revit MEP has developed add-ons for air duct sizing.

Thomas,

A company that can control the interoperability between BIM and its add-ons becomes a winner in this competition. I agree with you on your concern about Autodesk's domination on BIM software, as it is currently the only software company could be able to create Revit-friendly add-ons to fulfill the seamless transition of a model between every software. Collaborations between multiple companies to create a public BIM tools to transfer models between software are good, but then it might lead to an interest group of these companies controlling BIM industry because there is no such thing as a free lunch. 

Milligan - Blog Post 2

B2: BIM

BIM Handbook Chapter 2: BIM Tools and Parametric Modeling

It is not very easy to define what “BIM” is, but this chapter helped put the idea into a bit clearer of a perspective. It describes BIM design applications in three ways – as a tool, a platform, or an environment. These are three distinct views of BIM and help create a complete picture of what it is. At the level of considering BIM as a tool, it is able to carry out specific tasks to reach a specified outcome. Not all BIM tools are created equal, however. There are different predefined object databases, methods for creating new and updating objects, surface types available, drawing generation capabilities, and the limit to the number of objects it can handle. Considering BIM as a platform, it generates and manages data within a model for several uses, as opposed to one specified outcome. Each BIM platform has a different capability to handle certain levels of project detail, ability to interface with other platforms, and the data they store for management. Considering BIM as an environment takes it to a new level that incorporates data management across tools and platforms.

It was interesting to learn that BIM is just one subset of parametric modeling, which shares these aspects as a tool, platform, or environment. Evolving from basic 3-dimensional modeling of shapes and figures, parametric modeling first creates a family of objects that becomes its own element. This element contains information about its shape, but also rules, properties, and behaviors as well. There are several technologies that encompass a parametric modeling system. The first layer of parametric modeling is the ability to define complex shapes in a few parameters. The next layer is defining assemblies which automatically update when the parameters of any shape are changed. The final layer is the ability to link parameters across multiple shapes, with the program automatically updating when needed.

Like all programs and tools, parametric modeling has strengths and limitations. One of the major strengths of this modeling system is the “intelligent design behavior” of objects. This refers to the ability of the program to automatically update and edit when needed, and is aware of the type of object it is editing and the rules and parameters that go along with it. This increases the complexity of the BIM program, which demonstrates one of its limitations. It can take quite a while for a user to become proficient and efficient at using the program. BIM also holds an advantage over basic 3D modeling software (such as SketchUp) in that it can link objects together in intelligent and meaningful ways, easing the design process.

Source: BIM Handbook Chapter 2: BIM Tools and Parametric Modeling

Comments

Jordan: I found your blog post to be particularly interesting, especially since through my co-ops and part time work I have been working on the owner's/facility manager's side of work. You said that the executive summary indicated that BIM can be used for analyzing and complying with codes which I find really interesting. Where I work part time at the moment, we are constantly working to figure out if our renovation ideas are code compliant. I am curious as to how BIM could be used to assist in this process, as I am sure it is more efficient and accurate than our current methods.

Mark: Having read the same chapter as you, it was nice to get a different perspective on the reading! One thing you mentioned that I did find somewhat interesting in our chapter was the idea of different BIM programs for different applications, even within the building and construction industry. I wish that the chapter had gone a little more in depth about the differences, but found the idea itself to be interesting. I wonder if there will ever be a master BIM program to rule them all, which is able to provide for the needs of all aspects of our industry.

Cody: You bring up a great point that BIM becomes increasingly important as IPD and similar projects gain momentum. It is critical to use collaboration technologies, such as BIM, to efficiently utilize IPD and other integrated methods. Also, I knew that some BIM programs were preferred over other by certain firms or people, but I didn't know that there was a difference in preference between architects and engineers. It is interesting that you describe a similar process taken by both architects and engineers when using BIM, yet there are still programs that are more tailored for certain parts of design.