BIM Basics: Possible Elements of a 3D BIM Model

When creating a 3D BIM model of a structure, the elements to be included in the model can vary depending on the end-users needs. A BIM model can be as simple or as complex as the user needs. The LOA and LOD apply directly to the structure and the elements of the structure being modeled. So before starting the model, knowing the elements that need modeling is crucial. There are four categories that these elements can fall into. They are architectural, structural, mechanical, and exterior.

Architectural

Architectural elements are those elements of the structure that are most easily changed. These elements are not crucial to structural stability. Most often, these are the elements in which the end-user will be thinking about moving around, changing, or removing depending upon the scope of the project. Below is a brief list of examples of these types of elements:

• Floors

• Walls

• Ceilings

• Roof

• Windows

• Doors

• Curtain System

• Stairs

• Railings

• Ramps

• Cabinetry

• Lights

As you can see from the list, these elements are fixed to the structure. Tables, chairs, etc., are not included in our standard list of architectural elements. These un-fixed objects can be modeled but add extra time to the modeling project.

Structural Elements

Structural elements of the model are those that pertain to the structural reliability of the building/structure. These elements, if removed, would cause major safety concerns and would be unwise to remove. It is important to know where these elements are to maintain and to work around their location. A few examples of these are:

• Columns

• Beams

• Trusses

Mechanical (MEP) Elements

One way to think of MEP elements is to think about major systems within the structure. Similar to the architectural elements, these elements are often of interest to the end-user and a reason why a 3D BIM model is being requested. Understanding how these systems work, what they look like, and what the LOD is is crucial to understand before taking on a MEP project. Some firms specialize in modeling these complicated MEP systems. Some examples of what could be included in these systems are:

• HVAC

• Ductworks

• Plumbing Fixtures

• Piping System

• Cable Trays

• Communication Devices

• Security Devices

• Lighting Fixtures

• Electrical Panels

As you might imagine, the complexity of these MEP systems will vary depending on the type of structure being modeled. As mentioned before, the LOD and LOA become really important when modeling these systems. With the varying sizes and materials of pipes and wires, understanding the size limit of what is in scope will save you a lot of time.

Exterior Elements

When considering the uses of a 3D BIM model, most people think of the interior of the structure. The value of what can be modeled on the exterior, such as walls, roofs, doors etc., is often forgotten. These elements can include:

• Parking Spaces

• Railings

• Sidewalks

• Ramps

• Plantings

• Lighting

• Stairs

• Paths

Having these elements in the 3D BIM model allows the user to experience and view the structure as it relates to the environment. Also, there is valuable info that can be gathered for outdoor maintenance and projects.

While the complexity of what can be modeled is far greater than what can be touched on here, understanding the basics of architectural, structural, mechanical, and exterior elements is an essential starting point to discovering what the end-user needs.