Project Description

1. Senior Project – Computer Science - 2005Frisbee Physics SimulationCharles GeorgeAdvisor – Professor Brian Postow Project Description This project began life as a simulation of the sport of Ultimate Frisbee. Due to time constraints, the project was constrained to a demo of Frisbee flight. This allowed me to create a simulation with a more fully realized physics system. Graphics All Graphics were rendered using Microsoft’s DirectDraw libraries. To achieve smooth animation, frames are pre- rendered to off screen memory, and copied quickly to the frame buffer, creating a smooth render every 1/30 of a second Input While the simulation itself is simple, the input system allows for expandability. It abstracts keystrokes, allowing either human or AI players to utilize the same set of avatar controls. This screenshot demonstrates the simple, functional, visuals of the game engine. The three meters on the bottom represent bank, roll and power of the initial Frisbee throw. The most challenging element of the physics is properly aligning all the vector components. Rotation matrices were used to adjust the coordinate system of the Frisbee. Parameters Varying a : Angle of Attack v : Velocity Parameter variables m: mass in kg d: diameter in mA: surface area in m2 Ro: air density in kg/m3 g: gravity Parameters Cx represent Aerodynamic coefficients, these Are constant and defined by Sarah Hummel in ISEA 2002 Frisbee Aerodynamics. Frisbee Flight Physics The flight of a Frisbee can be described as the combination of a gyroscope and a wing. The wing part of flight gives the Frisbee lift, and creates drag, while the gyroscopic elements stabilize the Frisbee. For this project I assume a throw with high spin, so stability does not need to be factored in. The three forces I calculate are Lift, Drag, and Gravity. The lift force and drag force are given above, along with the table of corresponding constants. The Angle of Attack, and Velocity along with the listed constants are used to calculate Lift and Drag according to the formulas above. These force vectors are summed, and the resulting vector is used to calculate acceleration. Acceleration is then used to calculate the new velocity, which is used to reposition the disk. Some images courtesy of Sarah Hummel, ISEA 2002 Frisbee Aerodynamics. Frisbee is a trademark of Whammo! inc