Digital Model–Based Project Development and Delivery: A Guide for Quality Management (2025)
Chapter: Appendix A: Glossary
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Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
APPENDIX A
Glossary
This glossary contains terms related to 3D modeling and quality management principles that are relevant to project development and delivery.
| Asset | Fixed facilities within a transportation network that are managed and operated by public agencies. See also Facility |
| Asset Category | Primary or top-level classification used to catalog transportation assets. Priority asset categories for agencies include bridges and structures, pavements, drainage networks, traffic safety, and intelligent transportation systems. |
| Asset Class | The second level of cataloged assets within an asset category hierarchy. |
| Attribute | Nongraphical data that is part of a model element definition. Modern modeling software includes property fields that can be used to embed pay item numbers as attributes to elements in a 3D model. See also Nongraphical Data; Property |
| Audit Date | The date on which the quality documentation was audited. |
| Auditor | The person who audits a project’s quality documentation. |
| Back Checker | The person who goes over the reviewer’s comments and markup and resolves issues or areas of nonconcurrence. This person may also be the originator. Some state departments of transportation do not require back checks for design reviews. |
| Back Check Date | The date on which the back check was completed. |
| BIM Execution Plan (BEP) | A plan to manage the use of BIM, especially in collaboration and information delivery, to accomplish project goals. See also BIM Manager; Building Information Modeling (BIM) |
| BIM Manager | The individual, normally identified in a BEP, who is responsible for overseeing BIM usage on a project. See also BIM Execution Plan (BEP); Building Information Modeling (BIM); Model Author; Model Manager |
| Building Information Modeling (BIM) | The use of a shared digital representation of a built asset to facilitate design, construction, and operation processes and to form a reliable basis for decisions [ISO 19650-1:2018(E)]. See also BIM Execution Plan (BEP); BIM Manager |
| Calculation | A mathematical process requiring a manual or automated way of extracting numerical data via formulas, equations, or computer programs to achieve a numerical solution or interpretation of data. |
Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
| Certification | Verifies that the design has been completed to the agency’s specifications and in alignment with a comprehensive quality management framework. |
| Certifier | The discipline lead or design manager who certifies that the design was completed to the agency’s specifications and in alignment with a comprehensive quality management framework. Typically, only final deliverables are certified. |
| Check | The act of inspecting or testing something to determine its accuracy or quality. |
| Clash Detection | A technique used in BIM or digital delivery processes to identify conflicts or collisions between various model elements. See also 3D Coordination |
| Common Data Environment (CDE) | The agreed-upon source of information for a project or asset, which is used for collecting, managing, and disseminating each information container through a managed process [ISO 19650-1:2018(E)]. |
| Computer-Aided Design and Drafting (CADD) | The process of creating computer models based on identified parameters. |
| Contract Documents | A collection of clearly identifiable documents describing the requirements and terms for a project. Contract documents typically include plans, specifications, and working drawings. Specifications define plans and working drawings, as well as how to coordinate contract documents in the case of a conflict. Models or CADD documents may be included in the definition of plans and working drawings or defined as specific contractual entities in the specifications or special provisions. |
| Correction Date | The date on which corrections were completed. |
| Corrector | The person who made corrections in the design documents. This person may be the originator. |
| Data Exchange | The process of working with data that is structured under a source schema to transform and restructure it into a target schema. This enables the target data to be an accurate representation of the source data within specified requirements and with minimal loss of content. |
| Design Authoring | The process of using 3D design or modeling software to develop 3D models based on specific roadway and structural criteria to convey design intent for construction. Core functions of design authoring include development and analysis of design elements, while the functions of modeling software include the development of 3D objects. Depending on the discipline, the design authoring software can be the same as the modeling software. |
| Design Element | A component of a model that represents a physical object (e.g., a sign) or abstract concept (e.g., alignment or north arrow). |
| Design Review | The process of using a 3D model to review and provide feedback related to multiple aspects of design, including evaluation of design alternatives and environmental constraints, review and validation of geometric design criteria, and assessment of completeness or quality of overall design. |
Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
| Digital Record | A file that contains data stored in a digital format. See also Quality Artifact |
| Discipline | The field or area of the content being reviewed. See also Functional Area |
| Discipline-Specific Model | A model or linked models related to a single discipline. The superstructure model, substructure model, and detailing models are linked together into a federated structural discipline model. See also Federated Model |
| Documentation | Documents or records used to preserve and track various aspects of the review process. |
| Document Type | The type of document being reviewed (e.g., calculations, design model), which could come from a lookup list. |
| Facility | Any physical asset within a transportation or roadway network (e.g., roads, bridges, tunnels, overpasses, and rest areas). |
| Federated Model | A model that is compiled by referencing other models together using a common spatial reference frame, commonly used to combine all discipline-specific models together to represent a project as a whole. However, when an individual discipline uses multiple models to develop a discipline-specific design, a federated model can be used to represent a single discipline. See also Discipline-Specific Model |
| Functional Area | The subdiscipline of reviewed content. See also Discipline |
| Graphical Data | Data conveyed using shape and arrangement or location in space. Graphical data includes spatial data and nonspatial data. See also Spatial Data; Nongraphical Data |
| Industry Foundation Classes (IFC) | A nonproprietary data schema and format to describe, exchange, and share the physical and functional information for assets within a facility. See also Open Data Format |
| Layer | A means of segmenting data within a file, similar to a level. Model entities are assigned a layer, and layer properties can be used to control the visual style as well as the editability and visibility of elements on the entire layer. |
| Level of Information Need (LOIN) Specifications | The minimum requirements for each model element within a discipline or project model. LOIN defines both the level of detail of the geometry and the level of information attached to model elements. A LOIN specification may define requirements for the final deliverable, or it may be a progressive specification with increasing detail and information provided at successive milestones. |
| Library | A software resource file with configurations or utilities that improve the software’s usability. A library may contain object definitions, styles, scripts, property sets, configuration data, and more. Libraries are generally developed to reflect the agency’s model development standards and packaged into the modeling software configuration. |
| Metadata | Information that describes the characteristics of a dataset. This information may include structural metadata, which describes data structures (e.g., data format) and descriptive metadata, which describes data contents (e.g., roadway design). Metadata is used to describe and manage documents and other information containers. |
Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
| Milestone | The stage of the project development life cycle in which the review occurred. Each milestone must be populated by a lookup list. |
| Model | A representation of a system that enables the system properties to be investigated (EN ISO 29481-1:2016). |
| Model Author | The individual, normally identified in a BEP, responsible for creating a specific model element or group of model elements. See also BIM Manager; Model Manager |
| Model Element Table (MET) | A classified list of model elements. A MET can be used to create a model progression specification, which describes how elements of discipline-specific models increase in LOIN throughout the design process. The MET can also be used to document the quality management process. |
| Model Manager | The individual, normally identified in a BEP, responsible for a discipline-specific model. Model manager responsibilities are normally documented in the BEP. Typical responsibilities include managing design authoring within the discipline-specific model and implementing quality procedures for the discipline. See also BIM Manager; Model Author |
| Nongraphical Data | Data that describes attributes and properties of a model element that do not relate to its physical dimensions or location. A globally unique identifier is a common nongraphical attribute. See also Attribute; Graphical Data; Property |
| Open Data Format | Data structured according to a schema that has been published in a format that is free to use and redistribute. Open data formats are frequently supported by software products, enabling the exchange of data. See also Industry Foundation Classes (IFC); Proprietary Data Format |
| Originator | The individual responsible for the content that is being reviewed. |
| Project Identifier | A project number or another identifier that can be used to connect review documentation to the project dataset. |
| Property | Nongraphical information that describes a model element. For instance, the modulus of elasticity is a property of a material (e.g., steel). See also Attribute |
| Proprietary Data Format | Data that is structured according to a proprietary schema, which means it can usually only be read and written by one vendor’s software products. See also Open Data Format |
| Quality Artifact | An auditable record of quality checks that have been performed. See also Digital Record |
| Quality Assurance (QA) | All the planned and systematic activities necessary to confirm that a product or facility will perform satisfactorily once in service. The three key components of QA are quality control, independent assurance, and acceptance. |
| Quality Control (QC) | Actions and considerations necessary to assess production and construction processes to control the level of quality being produced in the end product. |
Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
| Reference | An information container (e.g., a 3D model) stored in a separate file and federated with a 3D model as a read-only backdrop. While the visibility and visual styles of a reference can sometimes be adjusted, data within the reference cannot be edited. See also Federated Model |
| Review | An assessment or examination of a design model. |
| Reviewer | The individual responsible for reviewing model content. |
| Reviewer Credentials | The reviewer’s certifications or other qualifications. Some DOTs require specific types of reviewers to be registered professionals, such as professional engineers, structural engineers, or land surveyors. |
| Review Criteria | The standard or code against which the review is executed (e.g., design manual, standard code, checklist). |
| Review Date | The date on which the review was completed. |
| Reviewer Title | The reviewer’s professional title, included as a way to demonstrate the reviewer’s expertise to justify their position as a reviewer. Some DOTs have seniority requirements for conducting some review types. |
| Review Type | A description of the review’s specific purpose. |
| Rule Set | A collection of criteria for implementing an algorithm. Rule sets are typically used with clash detection algorithms, where they specify clearance envelopes around specific groups of model elements that would constitute a clash. |
| Saved View | A predetermined set of saved attributes including viewpoints, scale, render style, orientation, and object and display settings saved for future retrieval. |
| Spatial Coordination | The process in which models are interrogated to identify spatial conflicts. Spatial coordination can be partially automated using spatial clash detection algorithms. It can be applied within a discipline (e.g., to check for conflicts between rebar and post-tensioning) or across disciplines (e.g., to check for conflicts between foundations and subsurface utilities). See also Clash Detection |
| Spatial Data | Graphical data placed within a coordinate reference frame that is tied to a geographical coordinate system, which links the information to a physical location. Spatial data is often stored in 3D models and geographic information systems. See also Graphical Data; Nongraphical Data; Model |
| Transmittal Date | The date on which the originator submitted materials for review. |
| Verifier | The person who verified that corrections were adequately addressed. This person may be the reviewer. |
| Verification Date | The date that corrections were verified. |
Suggested Citation:
"Appendix A: Glossary." National Academies of Sciences, Engineering, and Medicine. 2025. Digital Model–Based Project Development and Delivery: A Guide for Quality Management. Washington, DC: The National Academies Press.
doi: 10.17226/29171.
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