Spring Force

Spring Force

Abstract class

extends Force

implements N/A

Introduction

Spring Force is a component which inherits from Force and applies a spring force to a group of edges assigned to it.

Fields

Accessibility	Type	Field Name	Description
public	float	constant	spring constant
public	float	targetLengthRatio	ratio which represent the resting length of the target divided by its original length

Methods

Accessibility	Return Type	Method Name	Description
public	void	setConstant	sets the value for constant
public	void	setTargetLengthRatio	sets the value for targetLengthRatio
public	Vector	calculateSpringForce	calculates spring force vector derived from calculation of Hooke's law

Physics/ Mathematics

Hooke's law

The spring equation can be denoted as

F = -k(l - l₀)

Where F is the force applied by the spring, k is the spring's stiffness constant, l is the current length of the spring and l₀ is the resting length of the spring.

Modification with targetLengthRatio

We use the targetLengthRatio to provide a more easily tunable parameter across the model, where l₀ may be of different values depending on the position/ location of different nodes/ edges. With r representing tragetLengthRatio and l_start representing the length at the time of the simulation start here, we calculate

*l₀ = r (l_start) and therefore,

F = -k(l - r (l_start))