Unified Particle Solver

An implementation of Macklin et. al's Unified Particle Physics for Real-Time Applications for both the CPU and GPU.

This physics simulation was implemented on both the CPU (leveraging the Qt framework) and GPU (using CUDA) as a final project for Brown University's graduate-level course CSCI2240: Interactive Computer Graphics by Evan Birenbaum '15, Logan Barnes '15, and Geoff Trousdale '15.

Overview

The simulation supports a variety of states of matter by representing the entire world as a large set of small, individual, and independent particles that are influenced by a set of constraints. The system supports the following physical phenomena with two-way interaction:

• Inter-particle collisions
• Rigid bodies with approximated stacking
• Friction
• Rope and cloth
• Fluids
• Gases

CPU demo scenes

The following demo scenes are built in the CPU application, labeled with appropriate key commands to bring them up:

• 1 - A collapsing sand pile demonstrating frictional effect on angle of repose
• 2 - Stiff stacks of rigid bodies
• 3 - Stable stacking of rigid bodies in the formation of a wall
• 4 - Chained rigid bodies acting as a pendulum
• 5 - A fluid caught and held by a rope
• 6 - Two fluids settling, demonstrating the Rayleigh-Taylor instability
• 7 - Solids sinking or floating based on density
• 8 - Gas particles interacting with a swinging rope
• 9 - A rigid body being stopped by friction
• 0 - Fluids trapped like a water balloon
• D - Gas particles emitted into a closed space
• S - Gas particles emitted into an open space
• W - I came in like a wrecking ball!
• N - Newton's cradle
• . - Resolution of interlocked rigid bodies
• V - A volcano erupting and settling

The following commands may also be useful:

• T - Toggle real-time or time-step mode
• Space - move forward by a time step during time-step mode
• R - reset the simulation
• C - toggle rendering of individual particles

GPU demo scenes

Note: This version of the program no longer uses the CUDA 7 cuSolver library allowing it to be run on CUDA 5 capable machines.

The following demo scenes are built in the GPU application, labeled with appropriate key commands to bring them up:

• 1 - A single rope demonstrating basic distance constraints
• 2 - A cloth created with a grid of distance constraints
• 3 - Two fluids settling, demonstrating the Rayleigh-Taylor instability
• 4 - A single stack of solid particles
• 5 - Multiple stacks of solid particles
• 6 - A grid of solid particles falling into a cloth net
• 7 - A giant ball of fluid being fluidy, and demonstrating surface tension
• 8 - A combo scene of solid particles, cloths, ropes, and an immovable sphere
• 9 - Hair...just hair
• 0 - Empty scene

Moving around in the scene:

• W - Move forward
• A - Move left
• S - Move backward
• D - Move right
• Mouse - Look around
• Left Click - Shoot particle into scene
• Space - Add fluid to scene at origin (not guaranteed to maintain stability)

Pretty pictures