API Docs for: 0.7.1
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RotationalLockEquation Class

Extends Equation

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.

Constructor

`RotationalLockEquation`

(
• `bodyA`
• `bodyB`
• `[options]`
)

Parameters:

• `bodyA` Body
• `bodyB` Body
• `[options]` Object optional
• `[angle]` Number optional

Angle to add to the local vector in bodyA.

Methods

`addToWlambda`

(
• `deltalambda`
)

Add constraint velocity to the bodies.

Parameters:

• `deltalambda` Number

`computeB`

() Number

Computes the RHS of the SPOOK equation

Number:

`computeGiMf`

() Number

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

Number:

`computeGiMGt`

() Number

Computes Ginv(M)G'

Number:

`computeGq`

() Number

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

Number:

`computeGW`

() Number

Computes G*W, where W are the body velocities

Number:

`computeGWlambda`

() Number

Computes G*Wlambda, where W are the body velocities

Number:

`computeInvC`

(
• `eps`
)
Number

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

Parameters:

• `eps` Number

Number:

`gmult`

() Number

Multiply a jacobian entry with corresponding positions or velocities

Number:

`update`

()

Compute SPOOK parameters .a, .b and .epsilon according to the current parameters. See equations 9, 10 and 11 in the SPOOK notes.

Properties

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.

`G`

Array

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

`maxForce`

Number

Max force to apply when solving.

`minForce`

Number

Minimum force to apply when solving.

`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.

`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.