twolinks

SwiftyTwoLinks and KotlyOtlyDobleDosLinks

iOS Files and Functionality

• ContentView.swift displays the 3D visualization of the double pendulum, and includes user controls
• ContentViewController.swift controls the objects used to render in SceneKit, and updates simulation at 1/60 second increments
• TwoLinks.swift models the physical behavior of the double pendulum
• TextSlider.swift implements a slider control with a text label above it, with semi-transparent background

Android Files and Functionality

• MainActivity.kt is the layout and scene manipulation features
• MainViewModel.kt controls resetting, pausing, or updating states
• TwoLinks.kt models the physical behavior of the double pendulum

Calculating Offsets and Pivot Points

There are five normalized values that define dimensions of the two link pendulum system. Each link has a length L, and a minimum distance d from its end where an attachment point can be defined. Three points are defined, the hinge point H about which the link rotates, the link center point C, and a pivot point P about which a second link rotates. The dimension x defines the distance from H to C, and the dimension y defines the distance from H to P. The diagram below references these dimensions, and explains how they are calculated using normalized values that the user controls.