Chapter Two of BIM Handbook

     Chapter 2 of this text focuses on the origin of technologies that have been updated throughout the past couple of decades and are still used as common 3D imaging tools. It defines the word behavior as the ability of how an object can update itself and a very important characteristic to maintain when incorporating new and customized features into new BIM programs. It also stresses that BIM environments can include many different architectural platforms so that accessing tools necessary to create any type of object can be made easier.

     The earliest modeling occurred in the 1960s and started with very basic 3D shapes that were able to be modified to a certain extent. Towards the late 1970s this had evolved into more complex structures such as the gable figure shown within the text. CAD systems soon joined within the 1980s but were not as well developed or user friendly as techniques most drafters and designers had gotten used to up until that time. After discovering that shapes could share parameters more shapes were able to be generated within the programs such as AutoCAD and older methods were allowed to be updated as well. Parameters can be thought of as objects that are able to be altered, given specific rules or properties and also be connected to other objects. 
     Much of the processes to create parameters is found within “if-then” statements but had not evolved tools to allow for complex curved shapes. Along with that, the programs were starting to also incorporate self-fixes within the modeling design process which proved to be a lot less work in the end than previous 3D techniques done by hand.  

     Eventually the chapter starts leading up to current generation of BIM tools and the modeling of current structures. They discuss many of the programs that can be included within the BIM environment and how parametric design works. First topic discussed is wall construction and the rules associated with that. Next, they proceed to explain more complicated figures such as difficult design connections. The book goes on to describe several different technologies combined to form a modern parametric modeling system followed by “Base Object Families” that are designed to work well with each other within BIM Architectural Design Applications.  

     Further sections describe what to do when a certain capability does not exist in any BIM tools, how to create user defined objects and which types of libraries can be useful resources since parametric objects are ever-evolving. A common issue that many users have with BIM and associated programs has to do with scalability. This issue leads to usage of a program becoming bogged down when files get too large to process quickly. To overcome this problem, object management can be a good technique to abide by. The last few sections of the chapter discuss Revit in further depth along with the interfaces it works well with depending on the specialist using or creating the file. It defines them as either a tool, platform or environment while listing specific strengths and weaknesses of each as well. 

     After reading other posts within my group, I notice that I am not the only one who did not imagine how much is done in the background to make all of the most useful BIM programs work well with each other. I also had no idea that this design process dates back to the 1960s. This is good because many different types of expertise need to utilize these types of tools to be successful and this software makes it even easier to exchange information and integrate everyone well. 

Comments:

Nay Ye Oo - Thank you for concentrating on the history sections of this chapter. I as well reached the same conclusions you did about CAD being a bit more "rugged" as compared to BIM, especially after reading the chapter. I think it is very interesting that although BIM is more widely used that it is not taught as often as CAD like programs.

Sarina - I like how your post includes a lot of the up to date applications that are considered to create a BIM "environment". It really helps provide a quick summary of the end of the chapter where many different interconnected interfaces are described further in depth. I agree that with the way technology has advanced in the past 50 or so years, that there is no stopping when it comes to the level of detail we can and will achieve in order to keep improving.

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