A simple 0-to-3 scale (from the UK BIM Task Group) describing how far a project has moved from isolated 2D drawing toward fully collaborative, data-rich BIM:

• Level 0 - unmanaged CAD, paper or digital drawings, no collaboration standard.
• Level 1 - managed CAD, some 3D, a shared CDE for drawings but each discipline still works separately.
• Level 2 - collaborative 3D models per discipline, federated together, exchanged via a common format (this is where ISO 19650 workflows live).
• Level 3 - a single shared, cloud-hosted model that every discipline edits directly (still more aspiration than everyday practice for most of the industry).

Most real projects today operate at Level 2 - which is exactly what ISO 19650 was written to standardize.