The procedures outlined in this document describe how 3D reference objects are designed and revised by the Medical Illustrator, and how subject matter experts (SMEs) are selected, as well as how these experts review and approve these 3D reference objects. Models appear under the 3D Reference Object Library on the CCF Portal and are used in the Registration User Interface (RUI) and Exploration User Interface (EUI). The 3D reference objects are a critical part of the evolving Human Reference Atlas. See (Börner et al. 2021) for background information. This document is intended for medical illustrators and subject matter experts (SMEs) involved in the 3D reference object approval process, many of whom are organ experts from funded components of HuBMAP or other projects.