Real-Time Fire Simulation




Santikongka, Sarayuth

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UTSA Department of Computer Science


Natural phenomena simulations (e.g. fluid simulations) are used in variety of applications including game and movie production. Fire simulation, in particular, is extensively used in many games. On game systems, interactive response to the user is a crucial constraint, and interaction with the environment (including interaction with characters) is also an important property. Normally, the time to take for realistic fire simulations to generate a frame can not satisfy the timing constraint of games. This thesis develops a new physics-based simulation technique which capable of creating realistic (or at least plausible) results in real-time.

The simulation technique can be divided into four components: A physics-based particle system, fire volume generation, fire rendering, and smoke simulation. The physics-based particle system is used to control movement of simulated fire and smoke; each particle in the system is utilized as a control point in the later simulating processes. Every particle possesses its own physical properties such as acceleration, velocity, temperature, and density. The particle system is controlled using the Smoothed Particle Hydrodynamics (SPH) method. SPH manipulates the motion of each particle depending on its neighboring particles and its own physical attributes. This physics-based particle system can enable the simulation to interact with the environment physically. Fire volume generation utilizes particles from the particle system to create small-size polyhedra. The final volume of fire from the generation process is the integration of these polyhedra. After this process, the generated volume will look relatively like a burning fire; however, it consists of only small polygons. Small-scaled detail is needed to make the results more realistic. Fire rendering technique is utilized for this simulation to transform sharp-edge polygons into more realistic forms. Naturally, fire can create smoke; therefore, a new smoke simulation technique is included in the simulation. The smoke simulation is also based on a particle system. For each particle, a grid system is created that depends on the particle’s physical properties. The smoke is constructed from these per-particle adaptive grid systems.

This simulation is expected to generate moderate-scaled fire in real-time (20 – 30 frame per second) on a typical gamer PC. The details of the simulated fire can be controlled by some parameters and more particles can be used to create more stable fire or larger fire with higher detail. This simulation technique is also expected to be able to generate the fire in game and movie production.





Computer Science