BIM Handbook chapter 2 overview

Before reading this chapter, I have never heard about the BIM software. I thought it was particular software used for architecture. After reading through the summary, I have learned the content of Building Information Modeling (BIM) applications, which represents objects by parameters and rules that determine the geometry as well as some non-geometric properties and features(20). So people can change the shapes and properties of objects by the way of changing parameters. The convenient is that only by changing the code of the object, all the same materials in the building will be changed accordingly. For example, all the windows in the building can be changed from 2ft*1ft to 2ft*2ft by changing the code. The revolution makes the whole process simplified and facilitates the design of large and complex models in 3D.

Although the BIM technology goes through a long way to today’s situation and improves more since it was first developed 1980s, the principle remains the same, which is defining each object as a node with parameters then connects them together to make a larger assemblies. The improvement reflects in the portion of update. For early parametric modeling system, the whole model was rebuilt however in the modern parametric modeling system, only regenerate affected parts are updated.(44) Therefore minimizing the calculation and make the model can design more complex building.  Referring to the post of G. Carpenter, early BIM also had  other shortcomings, notably (a) designers who were more comfortable with 2D drawings and (b) cost of each seat ("upward of $35,000 per seat"). 

 However, each type of object has its own properties and within different BIM, the way of definition is different. For example, we can’t transform a model from Revit to Bentley Architecture. Each BIM has its own advantage and disadvantage. Understanding the function of each software well can help a lot on choosing appropriate one.

Revit is the best known software in the architectural design. It includes an excellent object library that supports a multi-user interface(58). However, if size of the project is bigger than 220 megabytes, the software will be significant slowed down and it isn’t good at curved surface drawing.

Compared with Revit, Bentley is powerful on complex curved surfaces, including Bezier and NURBS. It allows user to define parametric objects to fulfill their desired building model. It allows a project with bigger size and therefore more complex. However, it is not very friendly with other software and it is hard to learn.

Another software I am interested in is AutoCAD-based application because I have used AutoCAD for drawing. The advantage of this application is that its easy adoption. However, the applications are not parametric based so people must manually change the drawing. So I think in future it will be eliminated.