What is I3S?
The I3S (Indexed 3D Scene Layer Specification) is a format for large 3D Geo datasets. The specification is especially designed for streaming large 3D data over the web. The specification originates from Esri and was adopted as a Community Standard by the OGC (Open Geospatial Consortium) in 2017. An I3S dataset is also called a Scene Layer.
What is an SLPK?
A Scene Layer Package (SLPK) is a file format for the storage/exchange of one I3S layer.