BIM objects

BIM objects are digital twins of the building elements. They are not just geometric models, but include all relevant information about the element, including physical, functional and logistical characteristics.

Table of contents

BIM object features

Each BIM object has a 3D geometric model that represents a building element that exists in the real world.The geometry can be modified based on parameters, allowing flexible changes to the size, shape and other geometric properties of the object.

The object contains information about the material, such as its type, density, thermal conductivity, but also its weight and load-bearing capacity.

In addition, the object also includes its function: you know that it is a door, a window, a pillar or other building element. It also knows its connection to other elements, for example, the wall and the door inside it are connected.

BIM objects contain manufacturer information, such as the manufacturer’s name, product part number, delivery date, but also information to help with installation, operation and maintenance.

By creating a digital twin (where an as-built model of BIM objects is linked to the building using smart devices), buildings can be operated much more efficiently, cheaply and predictably, which can prevent, for example, unplanned outages that cause losses.

Information such as costs (cost of materials, labour, etc.) and time-related data (date, duration, sequence, etc.) can be linked to the object, which can be of great help during the construction process:

BIM object types

All elements to be installed and mounted are also available in a digital version, for example:

Walls and wall systems

• Geometry: exact dimensions, location
• Materials: concrete, bricks, insulation materials, etc.
• Function: load-bearing or partition
• Logistics: manufacturer information, delivery, installation data

Doors and windows

• Geometry: dimensions, opening direction, location
• Materials: wood, metal, glass, etc.
• Function: entrance / interior door, ventilation window, etc.
• Logistics: maintenance information, life cycle data

MEP system

• Geometry: precise layout of pipelines, cable ducts.
• Materials: steel, PVC, copper, etc.
• Function: plumbing, electrical wiring, HVAC systems…
• Logistics: maintenance schedule, manufacturer information

Benefits of BIM objects

BIM objects are the information-carrying units on which the BIM methodology is based, and therefore have many advantages:

• the disciplines (architectural, structural, mechanical, electrical…) can be easily integrated, design errors can be detected in advance;
• all project participants have access to the same BIM model, improving communication and collaboration;
• predicted clashes and failures reduce the need for changes during construction, leading to cost and time savings;
• maintenance and operation tasks can be tracked throughout the lifecycle of the building, ensuring a more sustainable operation in the long term.

Objects not only provide valuable data during the design and construction phase, but are also key during the operation and maintenance phase. Through integrated and detailed data, BIM objects contribute to more efficient, accurate and sustainable construction projects.

Creation of BIM objects

BIM objects produced in-house

Designers then have full control over the BIM objects, whether it’s detail, accuracy or updating.

Their advantage is that they can be precisely adapted to the needs of the designer, the client and the specific requirements of the project. They can be easily and quickly modified and are secure in the sense that they do not leak sensitive information to external parties.

Their disadvantage is that they are extremely time and resource intensive. They also require expertise to set up and maintain, cost money to buy the right software and tools and, of course, to train staff.

BIM objects from external sources

External BIM objects are “boxed products” and should only be used in certain circumstances.

Their advantage is that they can be used immediately, which can save time and even money on projects.

The disadvantage is that they do not usually meet the specific needs of the project and may have limited customisation. There may also be occasional incompatibilities and data leaks, and sharing sensitive information with external parties may pose security risks.

External BIM object sources:

• manufacturer libraries: manufacturers offer their own BIM objects of their products (e.g. RevitCity);
• BIM libraries and databases: online platforms offering BIM objects (e.g. BIMobject, NBS National BIM Library);
• expert service providers: companies specialised in the creation of BIM objects (e.g. BIMsmith).

There are advantages and disadvantages to using both in-house and externally sourced BIM objects. The choice of the best methodology depends on the specific needs of the project, the resources available and the design requirements. It is important that the BIM objects selected are compatible with the software used and provide the necessary accuracy and detail to successfully deliver the project.

BIM objects and classification

A construction project can involve many, even tens of thousands of BIM objects.

If we consider that an architect’s office usually manages not only one (or more) project, but also designs a hospital, a condominium or a high-rise warehouse, in addition to industrial facilities, we may wonder: how to navigate among all these BIM objects, so that they have a coherent structure, sufficient detail and do not contain too much unnecessary information.

The usability of BIM objects is created by a uniform classification.

Main classification systems:

• IFC (Industry Foundation Classes): an open standard developed by buildingSMART to enable the interoperability of BIM data between different software.
• OmniClass: a construction classification system used to categorise construction elements, materials and activities.
• Uniclass: a classification system for systems, products, processes and other construction activities used in the UK.

BIM objects can be classified into categories defined by classification systems so that they can be stored and managed using a single data structure. This allows us to quickly locate and identify them in digital models, making any query easier and clearer, something like this:

Clarity is also important because BIM objects store a wide range of information (dimensions, materials, functions, technical data, etc.) which, if not entered into the model according to a consistent logic, can lead to many misunderstandings. Classification makes the data of objects compatible and easy to exchange and manage between different project participants and systems.

This increases the reliability and usability of the models throughout the life cycle of the building (design, construction, operation and maintenance, retrofit, demolition).