In the src/GRANULAR/pari_gran_hooke_history.cpp file, the code checks if there is more than one rigid body. The documentation states that it is generally recommended to create one rigid body for computation time reasons, but multiple rigid bodies are allowed. There is some confusion regarding why this recommendation exists. Is it possible to comment out the relevant check code to allow for the creation of two rigid bodies?
You can have multiple rigid bodies with just one fix rigid command. Please check the documentation.