Bifröst Physics Arman J. Frasier Christopher Newport University Department of Physics, Computer Science, and Engineering Mentor: David Heddle April 22

Bifröst Physics

Arman J. FrasierChristopher Newport University

Department of Physics, Computer Science, and EngineeringMentor: David Heddle

April 22nd, 2011 Washington Room, David Student Union

Bifröst Physics Christopher Newport University Arman J. Frasier

Roadmap What is Bifröst Physics? The Physics The Programming Future Development Conclusion & Questions


What is Bifröst Physics? A two dimensional physics simulator designed

to facilitate long distance physics education through a local network or the internet.

Developed in Java


FeaturesPhysics Simulator Kinematics Inelastic Collisions Mutual gravitational and

electric effects Gravitational and Electric

fields Fluidic Resistance

Trajectory tracing Velocity vector display Automatic entity generation Optimized threading Alterable time iteration


FeaturesRenderer Accelerated 2D graphics

through AWT Maximum frame rate of 60

frames per second

Networking Integrated chat functions Ability to transfer

simulation data Centralized Relay Low bandwidth usage


Physics Steps through each entity, calculating the net

acceleration affecting that entity. Uses these accelerations in basic kinematic

equations, along with a specified time step, to determine the new velocity and position vectors of each entity.


Collisions The false positive check helps correct errors from large time steps.

Pseudo-code algorithm:

if(distance > (radius1 + radius2)) {//no collision (too far away)return;} else {rotate frame so that the collision vector becomes the new x axis} if (not false positive) {//collisiondo collision calculations}return frame to normal rotationreturn;

An example of a false positive collision


Collision Example

Detect collision Find collision vector Rotate the frame, making the collision vector x’.

Find the x-component of each entity’s velocity

21

212111

2)(

mm

ummmuv

21

111222

2)(

mm

ummmuv

Use the x-components in these 1D inelastic collision formulas to calculate new x-components.

Update the velocity vectors, and then return the frame to its original rotation.


Programming Simulation Programming Network Programming


Simulation Programming Upon initialization, the simulation control

thread creates as many worker threads as there are logical processors on the host machine.

These threads are synchronized using a sleep/interrupt schema.


Simulation Threading

Taskmaster Simulation Control

Worker Threads

(One per logical processor)

Aggregate Data

1 kHz

SimulationCalculations

Sleep

Proceed

Interrupt

Action

Thread

Legend

Update Entity Data

Play?

YesNo


Network Programming Central host accepts connections from clients Host sends physics data to clients Host acts as a chat relay for clients Low bandwidth usage


Future Development Networked simulation calculations Simulation video capture Further simulation optimization Extension into 3D Abstraction of Physics simulation with API


Conclusion Bifröst Physics can help students understand

complex physical concepts through instructor designed experiments, as well as through instructor led networked class sessions.


Questions?Resources Project Webpage (Includes jar files, user’s guide, change log, and this presentation)

http://www.pcs.cnu.edu/~afrasier/bifrost Contact: [email protected]

http://www.pcs.cnu.edu/~afrasier/bifrost

Documents

Bifröst Physics Arman J. Frasier Christopher Newport University Department of Physics, Computer Science, and Engineering Mentor: David Heddle April 22