Physics engine
The software component of Gazebo that computes rigid-body dynamics: contact forces, joint constraints, gravity, friction, and collision responses at each simulation timestep. Modern Gazebo uses DART by default; Bullet and Bullet-Featherstone are the supported alternative engine plugins. ODE (used in Gazebo Classic) is not a standalone engine plugin in modern Gazebo; it survives only as a collision-detector option inside DART. The physics engine operates on collision geometries, not visual meshes.
Defined in 2 GAGE programs, which carry 3 distinct definitions of it. The wording above is taught in Foundations of Robotics and Physical AI.
How each discipline defines it
The same term does different work depending on who is using it. These are the definitions as each program teaches them, unedited.
The software component of Gazebo that computes rigid-body dynamics: contact forces, joint constraints, gravity, friction, and collision responses at each simulation timestep. Modern Gazebo uses DART by default; Bullet and Bullet-Featherstone are the supported alternative engine plugins. ODE (used in Gazebo Classic) is not a standalone engine plugin in modern Gazebo; it survives only as a collision-detector option inside DART. The physics engine operates on collision geometries, not visual meshes.
The software core of a simulator that advances rigid-body dynamics, contact, and constraint equations through time. Gazebo and comparable robotics simulators wrap physics engines with sensor models, robot descriptions, and world scenes.
The mathematical component of a robot simulator that models forces, inertia, friction, and contact dynamics, stepping the simulated world forward in time according to the laws of rigid-body mechanics. Common examples include ODE, Bullet, and PhysX.
Terms it appears with
Not an alphabetical neighbourhood: these are the terms taught in the same lessons, ranked by how often they appear together.