B2: Chapter 2: BIM Tools and Parametric Modeling - Harvin Bhandal

In chapter 2 of the BIM Handbook, Eastman delves into different BIM tools and aspects of parametric modeling. He begins with the evolution of parametric modeling and its shift from 2D drafting to 3D modeling using computer softwares. The chapter discusses the importance of both predefined and user-defined rules in the BIM process. An object’s behavior is defined as “how [it] updates itself as its context changes” (in relation to defined rules). Each parametric object has certain attributes which makes it a lot more efficient to create and modify geometries. For example, a building element, such as a wall or door, is first defined by a class or family with rules that govern its parameters. As better put by Eastman, “Designing a building that contains a hundred thousand or more objects would be impractical without a system that allows for effective low-level automatic design editing”. 

In BIM application, the predefined objects and rules are mostly correspondent to existing design standards. For example, the standard practice for steel design is based from the AISC handbook. Eastman discusses certain scenarios where the industry standards cannot be used in the design model, and a designer has to create new objects. These scenarios include specific design conditions, aesthetic criteria, and new technology that has not been standardized yet. 

The chapter also compares different BIM platforms and discusses each of their strengths and weaknesses. Revit is the market leader in BIM software, and it is known for having user-friendly interfaces along with many useful development tools and libraries. As of now, I have no experience with Revit and I was a little apprehensive about having to use it in this class. However, this chapter emphasizes that the use of BIM platforms exist to make design tasks a lot less time-consuming and less error-prone. BIM has the capability to detect design clashes, which can alert the designer where changes need to be made. While Eastman states that often times it takes months to use a BIM design application proficiently, they are still very powerful tools and is necessary to use in many design scenarios. As the models are rendered in 3D, all parties involved in the project will have an easier time understanding certain components that may be difficult to interpret from a 2D drawing. Since the publication of this book in 2011, it appears that BIM has been growing as predicted and has had huge impacts on the ACE industry, saving both time and money for everyone involved.

Sources: 

Eastman, Charles M. BIM Handbook : A Guide to Building Information Modeling for Owners, Managers, Designers, Engineers and Contractors. Vol. 2nd ed, Wiley, 2011. EBSCOhost, http://web.b.ebscohost.com.ezproxy2.library.drexel.edu/ehost/ebookviewer/ebook/bmxlYmtfXzM2NDIzOV9fQU41?sid=bc728db5-ac2a-463a-be02-b1d1edcfc78a@pdc-v-sessmgr02&vid=0&format=EB&lpid=lp_71&rid=0

Comments to others:

To Alec Silverstone:

Alec, you present very good points and I agree that contractors should be involved, or at least informed of the design process. By providing contractors access to the BIM models, they will be able to get a better understanding of the project and see it in a 3D view. It also definitely would save time and prevent any issues by BIM’s ability to detect clashes. While it would be ideal that a contractor is involved in the design process, unfortunately I feel like many times that does not happen. During my first co-op, I worked at a construction claims consulting firm, and it was apparent that a lot of the issues that contractors encountered during the construction process (which invevitably caused the project to be delayed) was due to unclear designs and miscommunication. I think BIM has the potential to lower the frequency of these issues and make for a smoother construction process, especially if contractors are involved. 

To Christian Tait:

Christian, you highlighted a major issue that business and money can hinder the development of using BIM across different platforms. During my co-op, I always found it frustrating that it was not as intuitive to use files from AutoCAD and Microstation in tandem. While it's obvious that a company would only operate within its best intesest; ie making the most money, it is frustrating as a user that many programs do not work well together. Even though companies would claim there is no reason to have to interchange between programs, clients may have special requests for certain platforms to be used. Furthermore, users may be more familiar and proficient operating under a certain platform.

To Albert Hanan:

Albert, you did a great job discussing the evolution of parametric modeling and how it evolved into today’s uses. As I discussed in my post, the development of 3D modeling was a huge advancement and expanded the limits for design. The combination of the two classic modeling methods to produce the modern method truly shows how it is important to understand a product’s history in order to improve it. In this case, the best aspects from the CSG and B-rep method were combined to make modern parametric modeling both modifiable and easy to use.