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JSim

SimWorld

Yet-Another-Software-Suite/JSim

SimWorld¶

frc.jsim.api.SimWorld

Top-level entry point for the JSim physics simulation. Create one per subsystem (or share a singleton), add bodies, and call step() each robot loop.

Constructors¶

Signature	Description
`SimWorld()`	Default timestep (20 ms / 50 Hz) and 10 solver iterations
`SimWorld(double fixedTimestepSeconds)`	Custom timestep
`SimWorld(double fixedTimestepSeconds, int solverIterations)`	Custom timestep and iteration count

Body management¶

Method	Description
`SimBody addBody(SimBodyBuilder)`	Build and register a body; returns the handle
`void removeBody(SimBody)`	Remove a body and its actuator from the simulation
`List<SimBody> getBodies()`	Read-only list of all bodies in insertion order
`SimBody findBody(String name)`	First body with the given name, or `null`
`SimBody findRobot(RobotId id)`	Body registered with the given alliance/station, or `null`

Force generators¶

Method	Description
`void addForceGenerator(ForceGenerator)`	Register a custom force generator
`void removeForceGenerator(ForceGenerator)`	Unregister a force generator
`DragForce addDragForce(SimBody, double linear, double angular)`	Create and register velocity-proportional drag
`MagnusForce addMagnusForce(SimBody, double k)`	Create and register Magnus lift for spinning bodies

Simulation control¶

Method	Description
`void step()`	Advance by the configured fixed timestep
`void step(double dtSeconds)`	Advance by an explicit timestep (breaks determinism if varied)
`double getTimestep()`	Returns the configured fixed timestep in seconds

Example¶

SimWorld world = new SimWorld();

world.addBody(new SimBodyBuilder("Floor")
    .planeCollider(0, 0, 1, 0)
    .material(Material.CARPET));

SimBody robot = world.addBody(new SimBodyBuilder("Robot")
    .robotId(RobotId.BLUE_1)
    .mass(54)
    .boxCollider(0.3, 0.3, 0.15)
    .noGravity().fixedRotation()
    .material(Material.CARPET));

// In simulationPeriodic():
world.step();
Pose3d pose = robot.getPose();

See also¶