Announcement: Want to get your hands dirty and provide your thoughts or ideas for a proposed external shape model library? While the hope is to provide an API for ISIS, the author also wants it to be independently useful. Another goal of the API is to help support small (irregular) body cartography.
see: ISIS External Library Dependency API Design - Planetary Shape Model and Ray Tracing System (PSMRTS). https://github.com/DOI-USGS/ISIS3/discussions/5309. Comments are likely best to be posted to this GitHub discussion site.