Class AngleLockEquation

Locks the relative angle between two bodies. The constraint tries to keep the dot product between two vectors, local in each body, to zero. The local angle in body i is a parameter.




B: number
G: Vec2

The Jacobian entry of this equation. 6 numbers, 3 per body (x,y,angle).

a: number
angle: number
b: number
bodyA: Body

First body participating in the constraint

bodyB: Body

Second body participating in the constraint

enabled: boolean

Whether this equation is enabled or not. If true, it will be added to the solver.

epsilon: number
index: number
invC: number
lambda: number
maxBias: number

Cap the constraint violation (G*q) to this value.

maxForce: number

Max force to apply when solving.

maxForceDt: number
minForce: number

Minimum force to apply when solving.

minForceDt: number
multiplier: number

The resulting constraint multiplier from the last solve. This is mostly equivalent to the force produced by the constraint.

needsUpdate: boolean

Indicates if stiffness or relaxation was changed.

offset: number
ratio: number

The gear ratio.

relativeVelocity: number

Relative velocity.

relaxation: number

The number of time steps needed to stabilize the constraint equation. Typically between 3 and 5 time steps.

stiffness: number

The stiffness of this equation. Typically chosen to a large number (~1e7), but can be chosen somewhat freely to get a stable simulation.

timeStep: number

The default relaxation when creating a new Equation.


The default stiffness when creating a new Equation.


  • Add constraint velocity to the bodies.


    • deltalambda: number

    Returns void

  • Computes the RHS of the SPOOK equation


    • a: number
    • b: number
    • h: number

    Returns number

  • Computes G*W, where W are the body velocities

    Returns number

  • Computes G*Wlambda, where W are the body velocities

    Returns number

  • Computes G*inv(M)*G'

    Returns number

  • Computes G*inv(M)*f, where M is the mass matrix with diagonal blocks for each body, and f are the forces on the bodies.

    Returns number

  • Computes G*q, where q are the generalized body coordinates

    Returns number

  • Compute the denominator part of the SPOOK equation: C = G*inv(M)*G' + eps


    • eps: number

    Returns number

  • Multiply a jacobian entry with corresponding positions or velocities


    Returns number

  • Parameters

    • torque: number

    Returns void

  • Parameters

    • ratio: number

    Returns void

  • Returns void