> For the complete documentation index, see [llms.txt](https://unfinishedstudios1.gitbook.io/fp-motion/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://unfinishedstudios1.gitbook.io/fp-motion/components/spring-system.md).

# Spring System

## Description

> In engineering and physics, a *Spring System* or *Spring Network* is a model of physics described as a \[graph]\(<https://en.wikipedia.org/wiki/Graph_(discrete_mathematics>) "Graph (discrete mathematics)") with a position at each vertex and a \[spring]\(<https://en.wikipedia.org/wiki/Spring_(device>) "Spring (device)") of given stiffness and length along each edge.

With *FP Motion*, the *Spring System* is the part of the asset that allows developers to **produce motion effects** like: [Lean](/fp-motion/components/motion-effects/lean.md), [Bob](/fp-motion/components/motion-effects/bob.md)...etc

The [Handle ](/fp-motion/components/untitled.md)class contains all the spring code; every component that uses the spring system holds an instance of this class, as it is the ‘bridge’ between it and the [Motion Manager](/fp-motion/components/motion-manager.md).

## How does it work?

In order for the *Spring System* to work its magic, it first needs to have an object designated as a target, in *FP Motion* we do this by **subscribing** that object to the [Motion Manager](/fp-motion/components/motion-manager.md) trough a component (usually on that same object).

Once you subscribe the object to the manager, the latter will create and return a [Handle ](/fp-motion/components/untitled.md)for it, which is the component in charge of **calculating the spring physics**.

Once the object gets a [Handle](/fp-motion/components/untitled.md) value, the [Motion Manager](/fp-motion/components/motion-manager.md) having now registered and created a spring system for it will update the object’s physics every frame.

The system works in the following way:&#x20;

1\. Take a force.&#x20;

2\. Calculate the effect that force produces on an object.&#x20;

3\. Changes the object's state (Position, rotation and scale) to match.

The resulting changes in position, rotation and scale are something we calculate using [Hooke's Law](https://en.wikipedia.org/wiki/Hooke%27s_law), and thus allow you to have access to a couple of parameters, making each force **interesting and unique**, while keeping the precision that some games need.