BIM Basics

What is Building Information Modeling (BIM)?

Building Information Modeling (BIM) is a digital representation of physical and functional characteristics of a building or infrastructure. It is a collaborative process that allows stakeholders to visualize, design, simulate, and manage the construction and operation of a facility in a virtual environment.

The Core Concept:

Consider BIM to be a digital version of a building, although it goes well beyond a basic 3D model. Every component is covered in detail, including the electrical systems, HVAC, doors, windows, walls, and more.

This information is not just geometric data, but also properties like material type, cost, and maintenance requirements.

Key Components of BIM

  1. 3D Modeling: BIM uses 3D models to represent the physical and spatial aspects of a building. These models are detailed and can include architectural, structural, mechanical, electrical, and plumbing (MEP) elements.
  2. BIM Objects: Intelligent components within the model that carry specific data.
  3. Data Integration: BIM integrates various types of data beyond geometry, such as cost estimates, scheduling information, material quantities, and performance analysis. This data helps in making informed decisions throughout the project lifecycle.
  4. Collaboration: BIM facilitates collaboration among architects, engineers, contractors, and other stakeholders by providing a centralized platform for sharing information and coordinating workflows.
  5. Visualization and Simulation: BIM enables visualization of designs in 3D, improving understanding and communication. It also supports simulations for energy analysis, clash detection, and construction sequencing.
  6. Lifecycle Management: BIM supports the entire lifecycle of a building, from initial design and construction through operation, maintenance, and eventual demolition or renovation. It helps in managing and maintaining information about the building's components and systems.

Dimensions of BIM

Building Information Modeling (BIM) encompasses various dimensions that represent different aspects of information within a digital model of a built environment. These dimensions are often referred to as 3D, 4D, 5D, and beyond. Here is an overview of each dimension:

  1. 3D (Spatial Dimension): This is the basic representation of physical objects and spaces in a digital environment. It helps stakeholders visualize the building or infrastructure project in three dimensions, allowing for better design comprehension and spatial coordination.
  2. 4D (Time Dimension): Adds the element of time to the 3D model, linking it with scheduling information. Enables visualization of the construction sequence over time, helping in project planning, scheduling, and identifying potential clashes or logistical issues.
  3. 5D (Cost Dimension): Integrates cost-related information with the 3D model and schedule data. Provides cost estimation and management capabilities throughout the project lifecycle. It helps in budgeting, tracking expenses, and making informed decisions regarding materials and resources.
  4. 6D (Environmental Dimension): Incorporates environmental data into the BIM model. Facilitates analysis of energy use, lifecycle costs, sustainability assessments, and environmental impact.
  5. 7D (Facility Management): Extends the BIM model into the operational phase of the built asset. Supports facility management activities such as maintenance, repairs, renovations, and space management. It provides a comprehensive digital record for ongoing facility operations.
  6. 8D (Health and Safety): BIM 8D involves the incorporation of health and safety-related data and considerations into the digital model of a building or infrastructure project. he primary goal is to enhance safety planning, risk assessment, and management throughout the lifecycle of the built environment. This dimension focuses on identifying potential hazards, evaluating risks, and implementing preventive measures early in the design and construction phases to mitigate safety issues during operation and maintenance.
  7. 9D (Legal and Security): BIM 9D integrates legal and security considerations into the digital modeling and management processes of construction projects, contributing to enhanced compliance, risk management, and security throughout the lifecycle of the built environment.
  8. 10D (Operations and maintenance): BIM 10D integrates operational and maintenance considerations into the digital modeling and management processes of construction projects, facilitating efficient facility management and ensuring long-term sustainability and performance of the built environment.

Benefits of BIM

  1. Improved Coordination: Enhances coordination and reduces conflicts among different disciplines by detecting clashes early in the design phase.
  2. Cost and Time Savings: Optimizes construction schedules, reduces rework, and minimizes errors, leading to cost savings and faster project delivery.
  3. Enhanced Visualization: Provides stakeholders with a clear visual understanding of the project, aiding in better decision-making and client communication.
  4. Sustainability: Supports sustainable design by analyzing energy performance, material efficiency, and environmental impact during the design phase.
  5. Maintenance: The integration of models in the BOS could be relevant and used to facilitate maintenance operations (for example, to replace a luminaire, a precise date could be entered in the models, which will be traced in the BOS (Building Operating System) and will facilitate the management of a task).

Level of Development vs. Level of Detail

LOD is sometimes interpreted as Level of Detail rather than Level of Development. This Specification uses the concept of Level of Development. There are important differences.

Level of Detail is essentially how much detail is included in the model element. Level of Development is the degree to which the element’s geometry has been thought through – the degree to which project team members may rely on the information when using the model.

It is important to note that the international terminology regarding Level of Development and Level of Detail varies. Some countries refer to the Level of Development concept defined within this specification as the Level of Detail and use different numbering systems.

  • LOD 100: Conceptual design.
  • LOD 200: Schematic design.
  • LOD 300: Detailed design.
  • LOD 350: Construction documentation
  • LOD 400: Fabrication and assembly.
  • LOD 500: As-built or Facility management.

Examples de type de LOD

BIM Levels of Development (LOD)

LOD Official Definition from the American Institute of Architects Practical Interpretation (source: BIM Forum 2023 LOD Specification)
LOD 100 The Model Element may be graphically represented in the Model with a symbol or other generic representation, but does not satisfy the requirements for LOD 200. Information related to the Model Element (e.g., cost per square foot, tonnage of HVAC, etc.) can be derived from other Model Elements. LOD 100 elements are not necessarily geometric representations. Examples are information attached to other model elements: symbols showing the existence of a component but not its shape, size, or precise location; or space reservation volumes. In essence, if information about an element can be derived from the model but the element is not at LOD 200 it is said to be at LOD 100. Any information derived from LOD 100 elements must be considered approximate.
LOD 200 The Model Element is generically and graphically represented within the Model with approximate quantity, size, shape, location, and orientation. LOD 200 elements are generic placeholders but are recognizable as the components they represent (e.g. a pump, a light fixture, a beam, etc.). Any information derived from LOD 200 elements must be considered approximate.
LOD 300 The Model Element, as designed, is graphically represented within the Model such that its quantity, size, shape, location, and orientation can be measured. LOD 300 elements are sufficiently developed to fully convey the design intent for the represented item. Note that while neither the LOD definitions nor this Specification specify who models the element, designers rarely generate model elements higher than 300.
LOD 350 The Model Element, as designed, is graphically represented within the Model such that its quantity, size, shape, location, orientation, and interfaces with adjacent or dependent Model Elements can be measured. LOD 350 is intended to define requirements for model elements that are sufficiently developed to support construction-level coordination. This LOD usually requires craft knowledge, thus the caveat in the LOD 300 interpretation above that designers rarely generate elements at LODs higher than 300. It should be remembered, though, that neither the LOD definitions nor this Specification specify who models the element – if a design team has craft knowledge available, they might choose to develop elements to LOD 350 or higher.
LOD 400 The Model Element is graphically represented within the Model with detail sufficient for fabrication, assembly, and installation. Essentially LOD 400 describes a model element developed to the level of shop drawings – in most cases, if a project’s specifications call for shop drawings of an item, the project team might model the item at LOD 400. Thus, most models contain few LOD 400 elements.
LOD 500 The Model Element is a graphic representation of an existing or as-constructed condition developed through a combination of observation, field verification, or interpolation. The level of accuracy shall be noted or attached to the Model Element. LOD 500 does not indicate a higher level than LOD 400, rather it indicates that the element’s geometry is determined through observation of an existing item rather than design of a future item.

The stakeholders involved in different levels of LOD (Level of Development) BIM models (ranging from LOD 100 to LOD 500) can vary depending on the project phase and the specific requirements at each level. Here is a breakdown of stakeholders typically involved with each LOD:

LOD 100

  • Architects and Designers: They use LOD 100 models to convey basic conceptual designs and spatial arrangements to clients and stakeholders.
  • Clients and Owners: Request LOD 100 models to understand initial design concepts and project scope
  • Urban Planners and Authorities: Assess the feasibility of proposed projects within the context of city planning and zoning regulations.
  • Developers: Utilize LOD 100 models for initial project proposals and feasibility studies.

LOD 200

  • Design Professionals: Architects, engineers, and consultants use LOD 200 models to develop detailed designs and coordination between disciplines.
  • Contractors: Begin to use LOD 200 models for early-stage construction planning and coordination.
  • Fabricators: Review LOD 200 models for detailed component design and fabrication.

LOD 300

  • Contractors: Use LOD 300 models for detailed construction planning, coordination, and clash detection.
  • Subcontractors: Refer to LOD 300 models for precise installation and construction sequencing.
  • Facility Managers: Begin to utilize LOD 300 models for early-stage facility management planning and operations.

LOD 400

  • Fabricators and Manufacturers: Refer to LOD 400 models for detailed component fabrication and assembly.
  • Contractors: Use LOD 400 models for shop drawings, fabrication, and installation planning.
  • Owners and Operators: Begin to benefit from LOD 400 models for detailed facility management and operations planning.

LOD 500

  • Facility Managers and Operators: Utilize LOD 500 models for ongoing facility management, maintenance, and operations.
  • Owners: Rely on LOD 500 models for comprehensive as-built documentation and asset management.
  • Maintenance Teams: Refer to LOD 500 models for ongoing maintenance and lifecycle management of the facility.

Additional Stakeholders Across Levels

Regulatory Authorities: Ensure compliance with building codes and regulations at all-LOD levels.

Educational Institutions: Use LOD models for research, teaching, and training purposes across all levels.

Insurance Providers: Assess risk management and insurance requirements based on LOD models.

Each stakeholder group interacts with BIM models at different LOD levels to meet their specific needs throughout the project lifecycle, from initial design concepts to ongoing facility management and maintenance.

Concepts for Information management in BIM

In the context of BIM (Building Information Modeling), there are three important concepts related to information management:

  1. LOI (Level of Information):
    • Definition: LOI refers to the level of detail and amount of information included within a BIM model for each element or component.
    • Purpose: It specifies how much information is needed to meet the requirements of stakeholders at different stages of a project.
  2. LOD (Level of Development):
    • Definition: LOD defines the level of geometric detail and accuracy of information in a BIM element.
    • Purpose: It helps stakeholders understand the reliability and usability of BIM data at various stages of the project lifecycle.
  3. LOIN (Level of Information Need):
    • Definition: LOIN specifies the specific information requirements (what information is needed) for different project stakeholders.
    • Purpose: It ensures that the right amount and type of information are available to support decision-making and project requirements.

Key Differences

  • LOI focuses on the amount and depth of information within the BIM model itself.
  • LOD relates to the level of geometric detail and accuracy of the BIM elements.
  • LOIN addresses the specific needs and requirements of stakeholders regarding the information they require from the BIM model.

These concepts work together to ensure that BIM data is effectively managed and utilized throughout the lifecycle of a construction project.

LOD (Level of Detail) has given way to LOIN (Level of Information Need).

There are several main reasons for this change:

  1. Broader scope
    • LOD was limited to the level of detail in BIM models, neglecting other crucial information.
    • LOIN encompasses all project information, both geometric and non-geometric, providing a holistic view.
  2. Greater flexibility
    • LOD imposed rigid levels of detail, not always adaptable to specific needs.
    • LOIN allows you to define customised levels of information for each project.
  3. Improved communication
    • LOD could generate ambiguities and misunderstandings.
    • LOIN requires an explicit definition of information needs, reducing the risk of confusion.
  4. Better collaboration
    • LOD limited the involvement of other project disciplines.
    • LOIN encourages interdisciplinary collaboration, promoting better integration of expertise.
  5. Support for a complete life cycle
    • LOD was mainly used for design and construction.
    • LOIN applies to the entire building life cycle, from design to operation and maintenance.

Adopting LOIN enables more comprehensive, collaborative and efficient management of project information, resulting in better decision-making, reduced risk and optimised processes.

Sources

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