Reservoir rendering is divided in two different approaches.
The classic approach ReservoirGrid, and the big data with multi resolution handling GigaGrid.
Both are based on the same ReservoirAPI, but they differ in implementation.
ReservoirGrid is the classic implementation of the rendering, based on JCarnac3D-OGL rendering. It allows to load and display grdecl and resqml files.
Its limitation is the computer memory which reduces the sizes of the grid you can render.
GigaGrid was created to support big sizes of grid that can't fit in computer memory. A complete build to a new datamodel must be executed before rendering the grid.