Model-Based Definition (MBD) is used by companies to create, organize, and manage a fully defined 3D model that captures design intent and serves as the master product definition for the extended enterprise (*Madhavi Ramesh, Model-Based Definition eBook). If you’re new to model-based definition and/or engineering, you can use this list of terms to familiarize yourself with the language and terminology associated with MBD.


3D PDF- A 3D PDF is a file format that supports 3D geometry. Using a viewer, you can zoom, pan, measure, and section a 3D model in a 3D PDF file. In the same way a 2D PDF file won't allow users to modify the source document, a 3D PDF prevents them from making significant changes to the geometry.

Annotation- An element that describes a model or a feature of a model. An annotation could be a dimension, a note, a symbol, a datum feature symbol, a surface finish symbol, weld symbols, etc.

Annotation Plane- A datum plane or flat surface used in Creo to define the orientation of annotations.

ASME/ISO Standards- Major standards used for model-based engineering. Specifically, ASME Y14.5 & ASME Y14.41 and ISO 1101 & ISO 16792.

Combination State- A collection of display settings used in Creo to control the visibility of objects in a model. This is helpful for model-based definition due to the fact that you can create a combination state to show annotations and geometry.

Coordinate Measuring Machine (CMM)- A CMM is a device, often used in manufacturing, that measures the geometry of physical objects. CMM can be programmed in minutes using MBD. It provides an example of how downstream processes benefit from 3D annotated models.

Control Characteristics- Control characteristics, also known as key characteristics, capture and communicate the design intent and critical product information required for manufacturing. You can use control characteristics in the planning stage, to find or reuse model data, etc. Control characteristics provide a way to access information for manufacturing decisions without having to open the models in the Creo application or other CAD systems to verify the model data. In Creo, you can designate annotation elements as control characteristics.

Datum Feature Symbol- A type of annotation that represents a datum. A datum, according to ISO standards, is an exact geometric feature used to locate or orient tolerance zones for tolerance features of virtual conditions.

Datum Target- Designated points or areas that are used in establishing a datum.

Datum Reference Frame (DRF)- A set of three mutually perpendicular planes that constitutes a reference frame for dimensioning and tolerancing.

Geometric Dimensioning and Tolerancing (GD&T)- A system for defining and communicating engineering tolerances. It uses a symbolic language on engineering drawings and CAD models that explicitly describes nominal geometry and its allowable variation.

Geometrical Product Specifications (GPS)- The ISO term for GD&T, GPS is a symbolic language for communicating workpiece requirements on engineering drawings and CAD models.

GD&T Advisor- This is an extension to Creo that provides expert guidance on the application of GD&T and validation that it has been done correctly. GD&T Advisor ensures models comply with the relevant standard and are fully constrained.

Jupiter Tessellation (JT)- A neutral 3D file format used for product visualization. It may contain faceted data, boundary representation surfaces, product and manufacturing information, and text attributes either exported from the native CAD system or inserted by a PDM system.

Model-Based Definition (MBD)- The practice of specifying product information, such as materials and geometric dimensioning and tolerancing, from within a 3D CAD model.

Product Data Management (PDM)- A type of software that stores, organizes, and secures data across teams. PDM systems may also include sharing and reviewing capabilities to make engineering data more consumable for non-engineering teams.

Product and Manufacturing Information (PMI)- The non-geometric attributes in 3D CAD systems needed to manufacture product components and assemblies. PMI may include GD&T, 3D annotations, surface finishes, material specifications, and more.

STEP AP242- A widely used and shared neutral CAD format. It's used to represent 3D objects and related information, such as PMI.

Technical Data Package (TDP)- The complete technical product information including annotated 3D geometry, PMI, and metadata. The Technical Data Package is typically sent to suppliers, manufacturers, or customers.

Tolerance- The total amount that a specified dimension is permitted to vary. The tolerance is the difference between the maximum and minimum limits.

Tolerance Analysis- A calculation to determine the effect of the accumulation of tolerances on product requirements.