# closed-chain-ik/core

```js
import { ... } from 'closed-chain-ik/core';
```

### Classes

- [Frame](/tools/docs/closed-chain-ik/core/Frame.md): Base class for `Link`, `Joint`, and `Goal` representing a frame defined by a position and rotation in space.
- [Goal](/tools/docs/closed-chain-ik/core/Goal.md): A frame representing a target for a connected link to reach. The degrees of freedom set on a goal are the axes that are constrained, as opposed to the movable degrees of freedom of a joint. A goal cannot have children and can only be connected to a link with `makeClosure`.
- [Joint](/tools/docs/closed-chain-ik/core/Joint.md): A frame representing a kinematic joint with any combination of degrees of freedom. Each degree of freedom is an offset applied on top of the frame transform. Only links may be added as children and a joint may only have a single child.
- [Link](/tools/docs/closed-chain-ik/core/Link.md): A frame modeling a fixed connection between joints. Only joints may be added as children.
- [Solver](/tools/docs/closed-chain-ik/core/Solver.md): Solves the closure and joint target constraints of a system of frames using damped least squares. Every independent chain of joints found in the roots is solved separately.

### Functions

- [findRoots](/tools/docs/closed-chain-ik/core/functions.md): Finds the unique roots of the trees the given frames belong to, following closure connections so every connected tree is included.
- [saveRestPose](/tools/docs/closed-chain-ik/core/functions.md): Saves the current joint values of every joint in the tree as its rest pose and sets `restPoseSet` to `true`.

### Constants

- [DOF](/tools/docs/closed-chain-ik/core/constants.md): Degrees of freedom that can be assigned to a joint.
- [DOF_NAMES](/tools/docs/closed-chain-ik/core/constants.md): Names of the degrees of freedom indexed by `DOF` value.
- [SOLVE_STATUS](/tools/docs/closed-chain-ik/core/constants.md): Statuses returned for each independent chain by `Solver.solve`.
- [SOLVE_STATUS_NAMES](/tools/docs/closed-chain-ik/core/constants.md): Names of the solve statuses indexed by status value.