B2 - Group A - BIM Tools and Parametric Modeling

The second chapter of the BIM Handbook is entitled BIM Tools and Parametric Modeling, and provides an overview of the technology that distinguishes BIM design tools from other types of CAD programs.  The main benefit of object-based parametric modeling seems to be that since the objects being represented are modeled based on parameters and rules which are then used to choose the objects geometry and some properties of the object.  This means that if one of the parameters is changed by the architect or engineer, the objects can use the updated parameters to modify themselves and report their new dimensions or costs to other parts of the BIM program, such as an accounting or scheduling page.

The biggest difference between BIM and traditional CAD software is that by utilizing the parametric modeling in BIM, objects do not have to have every single aspect of their geometry manually entered into the program.  BIM programs allow users and companies to create families of objects which have certain parameters which layout the basic geometry and properties, but the users can then edit one set of parameters and create a new object without having to change every other dimension and property.  This makes it very simple for BIM programs to be used to create layouts much faster than traditional CAD programs, but can also lead to trouble with unusual designs, since the base parameters of the objects may be missing or think the design is impossible while the designer knows that it can be done.  Overall however, BIM tools make modeling buildings and other structures very simple and easy to do, and the designers can complete the plans faster and have a better idea of the quantities and materials involved in the project faster than they could using traditional CAD programs. .

Comments:

To J Schwakoff – I think that you have a great summary of the main points of the article and I definitely agree with your summary that the development of object-based parametric modeling was the catalyst in the switch from paper to computer aided drafting and design.  I do think that the fact that there is more to BIM than just the parametric modeling is something that not many people (myself included) talked about very much with this post, simply because it was easier to talk about the benefits of the model instead of all of the other features which BIM programs can perform.