Model-Based Definition (MBD), also known as Model-Based Design, is the use of 3D CAD models to provide specifications — such as geometric tolerancing, PMI, and other annotations —  for individual parts and assemblies.

3D modeling is the best way to design products. Yet 2D drawings remain the primary reference for dimensions, tolerances, and annotations at 90% of manufacturing companies. Making new 2D drawings from the master 3D model is time-consuming, and can introduce errors into the project. If design changes are made, it is a tedious job to update the entire series of related 2D drawings.

MBD can drive accuracy and efficiency into your engineering and manufacturing operations by avoiding the time and effort of creating 2D drawings to explain parts and assemblies. The information needed can be either displayed on the model in a familiar way for machinists, manufacturing engineers, and others in the manufacturing process, or new views can be created of specific parts of the model.

New views always linked

Any number of new views from the 3D Master can be composed and annotated for downstream usage. These views may be 2D or 3D in view as needed. For geometric dimensioning and tolerancing (GD&T), a build-in tolerancing advisor guides the user in placing tolerance notes on the part while preventing the user from creating an invalid tolerance.

Any new drawings created from the master 3D model remain linked and will automatically update if there are change orders. Creating 2D drawings direct from the 3D model eliminates the need for recreating GD&T data in downstream uses.

Mobile or desktop viewing apps are available for those who need to view data from the master model but do not participate in creating it. These viewers are free or inexpensive, and allow all team members to have accurate information at any time.

The benefits of Model Based Definition

By converting to the 3D Master method and Model Based Definition, companies can define 100% of the product definition using a single 3D dataset. This makes it possible to reduce costs and improve quality throughout the product development process. Engineers can increase the amount of design information reused from one project to the next. Manufacturing costs are optimized by reducing manufacturing tolerances.