Fabiko

A Java inverse kinematics library implementing the FABRIK algorithm.

The Fabiko library is a hard fork of the Caliko library.

The user guide can be found on the repository wiki.

Features

• FABRIK algorithm for 3D
• various joint constraints (Local Rotor, Global Rotor, Local Hinge, Global Hinge)
• ability to connect multiple IK chains together in a hierarchy
• visualization of IK chains

Important

This library does not implement the FABRIK algorithm for 2D.

Improvements over Caliko

• migrated build system from maven to gradle
• refactored entire library to use JOML for algebra operations instead of Caliko's own custom algebra operators
• reduced object allocations
• updated & improved JUnit tests
• migrated performance tests to jmh
• fix backward pass failing to constrain local & global hinges of non-base bones (doesn't seem to make any difference)

Cons

• no support for 2D FABRIK
• requires JOML

TODOs

• add GitHub action workflow for building releases automatically from conventional commits
• add prismatic joint/constraint
• refactor FABRIK algorithm to properly use Quaternions or redesign it to use Dual-Quaternions?

License

The library is licensed under the MIT software license.

Credits

• Caliko, a free open-source software (FOSS) implementation of the FABRIK (Forward And Backward Reaching Inverse Kinematics) algorithm created by Aristidou and Lasenby.
• JOML, a math library for linear algebra operations needed by 3D Applications.

Literature

Further details on the FABRIK algorithm itself can be found in the following paper: Aristidou, A., & Lasenby, J. (2011). FABRIK: a fast, iterative solver for the inverse kinematics problem. Graphical Models, 73(5), 243-260.

Structure

The library is a multi-module gradle project with the following modules:

The core module contains the core IK portion of the library and has a dependency on JOML

The visualisation module contains the optional visualisation component of the library which provides the ability to draw various IK structures/chains/bones and depends on the core Fabiko functionality as well as the LWJGL 3.3.5 library.

The demo module contains a demonstration of the library utilising both 2D and 3D IK chains in various configurations. It requires the fabiko-core, fabiko-visualisation and LWJGL 3.3.5 libraries.

Build and Setup

To build yourself:

git clone https://github.com/Elenterius/Fabiko

gradlew build

Usage

To include the library in your own project use the jitpack maven repository or download a release from GitHub.

repositories {
    maven { url 'https://jitpack.io' }
}

dependencies {
    implementation 'com.github.Elenterius:Fabiko:TAG'
}