Business Process Model and Notation (BPMN)

IDEF modelling and Business Process Modeling Notation (BPMN) are two common methods used for BIM-related business process modelling (Smith and Tardif, 2012). However, BPMN appears to be more popular nowadays and to date, BuildingSMART International, the buildingSMART Alliance, and the U.S. national BIM Standard committee have standardized on the use of BPMN.

The Object Management Group (OMG, 2011) has developed a standard BPMN. The primary goal of BPMN is to provide a notation that is readily understandable by all business users, from the business analysts that create the initial drafts of the processes, to the technical developers responsible for implementing the technology that will perform those processes, and finally, to the business people who will manage and monitor those processes. Thus, BPMN creates a standardized bridge for the gap between business process design and process implementation.

BPMN is the de-facto standard for process modelling (OMG, 2011). It provides support for modelling control flow, data flow and resource allocation. BPMN is an excellent way to map out flows and process relationships to help document and communicate how a process is performed or should be performed.

A model developed with the BPMN modelling tool is easily understandable for both business and IT professionals. It can automatically generate codes that can be used directly by IT professionals to develop applications (OMG, 2011). Moreover, the development of BPMN is an important step in reducing the fragmentation that exists among process modelling tools and notations (White, 2004), such as DFD and IDEFØ as described in the previous sections.

BPMN uses a small set of notation categories to develop business process models and is powerful enough to express the complexity inherent in business processes. The categories of elements are illustrated in Figure 4.4. The four basic categories of elements are as follows (White, 2004):

Figure 4.4: Business Process Model and Notation (BPMN) (Saluja, 2009, p. 47)

1) Flow Objects

There are three Flow objects including Event which is represented by a circle and is something that “happens” during the course of a business process;

Activity represented by a rounded-corner rectangle; and Gateway represented by the familiar diamond shape.

2) Connecting Objects

The Flow Objects are connected together in a diagram to create the basic skeletal structure of a business process. There are three Connecting Objects

that provide this function including Sequence Flow represented by a solid line with a solid arrowhead, Message Flow represented by a dashed line with an open arrowhead and Association represented by a dotted line with a line arrowhead

3) Swimlanes

Many process modeling methodologies utilizes the concept of swimlanes as a mechanism to organise activities into separate visual categories in order to illustrate different functional capabilities or responsibilities. BPMN supports

swimlanes with two main constructs including a Pool which represents a Participant in a Process. It also acts as a graphical container for partitioning a set of activities from other Pools and a Lane which represents a sub-partition within a Pool and will extend the entire length of it, either vertically or horizontally. Lanes are used to organise and categorize activities.

4) Artifacts

BPMN was designed to allow modelers and modeling tools some flexibility in extending basic notation and in providing additional context appropriate to a specific modeling situation. Any number of Artifacts can be added to a diagram as appropriate for the context of the business processes being modeled. Data Objects are a mechanism to show how data is required or produced by activities. BPMN specification pre-defines only three types of Artifact. They are connected to activities through Associations. A Group is represented by a rounded corner rectangle drawn with a dashed line. The grouping can be used for documentation or analysis purposes, but does not affect the Sequence Flow. Annotations are a mechanism for a modeler to provide additional text information for the reader of a BPMN Diagram.

Most BIM process mapping is developed using BPMN modeling tools. The reasons for adopting this approach over others such as IDEFØ are (Saluja, 2009) summarized below as:

i. BPMN provides businesses with the capability of defining and understanding their internal and external business procedures through a Business Process Diagram. This also gives organizations the ability to communicate these procedures in a standard manner. It is a standard maintained by the Object Management Group (OMG) with a richer set of capabilities for modeling business process than IDEFØ (Wix and Karlshoej, 2010);

ii. It has a better capability to express a business process. In particular, it uses 'swimlanes' to enable communication between actors to be visualized. This is not easy to do with IDEFØ but is critical to seeing where exchange requirements are needed in IDM (Wix, 2007);

iii. The notation has a conversion method to the Business Process Execution Language for Web Services which is emerging as a standard XML based approach for workflow control (Wix, 2007); and

iv. There is a possibility to better integrate with the detailed information exchange mapping initiatives used in the IDMs which are currently being developed for the National BIM Standard (NBIMS) as well as BIM Standards in other countries.