This diagram shows the integrated definitions used by STEP and STEP-NC models. In a STEP file, each ARM concept is stored as one or more instances of the integrated definitions — low-level details like cartesian points and bspline curves that are combined to describe concepts like product shape. Like a normalized database, these are designed to be stable for the long term (20+ years) and general enough for use with new ARM concepts as they appear.
The browser text search function is the fastest way to find a concept. Avoid Internet Explorer or Safari, they display the diagrams but do not have full SVG support for following links. All other browsers work fine. Updated 2020-10-29 with FDIS ballot