Apps similar to MuJoCo include Bullet Physics, which is free and open source. Other options are ProtoTwin, Matter.js and Open Dynamics Engine. In total there are four CAD Software like MuJoCo for Mac, Windows, Linux, Android and iPhone.
Bullet Physics SDK: real-time collision detection and multi-physics simulation for VR, games, visual effects, robotics, machine learning etc.
ProtoTwin is an advanced physics-based simulation platform for industrial automation and robotics. Users use ProtoTwin to help design and test their industrial machines in simulation before deployment to physical hardware.
United Kingdom
ODE is an open source, high performance library for simulating rigid body dynamics. It is fully featured, stable, mature and platform independent with an easy to use C/C++ API. It has advanced joint types and integrated collision detection with friction.
