Create or use STEP boundary-rep geometry. The most common use of STEP is to describe the CAD mathematical shape as a series of surfaces trimmed and connected by shared edges. STEP always describes products, so the shape information appears as a property of a product, often the only property. Tolerances attach to geometry to annotate the design with PMI information.

Assembly and Product

Create or use STEP assemblies. Assemblies have a product side and a shape side. The product side describes the structure from a bill-of-materials point of view, while the shape side describes the geometric positioning of all components.

Features and Other Data

While shape and assembly structure are the most common use, the STEP models can describe many different aspects of product design, and STEP-NC goes beyond that to describe manufacturing process that makes a design.