PyBullet

PyBullet wraps the Bullet physics engine with a friendly Python API. For beginners it is often the first “real” physics sim after browser visualization (Three.js): install pip package, load a URDF, step a robot.

It is lighter than Isaac and less research-default than MuJoCo for modern IL/VLA papers, but excellent for teaching contacts, joints, and cameras quickly. Many legacy tutorials still use it.

Learning Path role: Simulation intro — run random actions, record a short trajectory, then move to MuJoCo/ManiSkill when you need paper-comparable envs.