Craftium: An Extensible Framework for Creating Reinforcement Learning Environments

Most Reinforcement Learning (RL) environments are created by adapting existing physics simulators or video games. However, they usually lack the flexibility required for analyzing specific characteristics of RL methods often relevant to research. This paper presents Craftium, a novel framework for exploring and creating rich 3D visual RL environments that builds upon the Minetest game engine and the popular Gymnasium API. Minetest is built to be extended and can be used to easily create voxel-based 3D environments (often similar to Minecraft), while Gymnasium offers a simple and common interface for RL research. Craftium provides a platform that allows practitioners to create fully customized environments to suit their specific research requirements, ranging from simple visual tasks to infinite and procedurally generated worlds. We also provide five ready-to-use environments for benchmarking and as examples of how to develop new ones. The code and documentation are available at https://github.com/mikelma/craftium/.