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Structural Modeling of Flames for a Production Environment. Eric Hielscher CS 777. Reasons not to use a simulator. Numerical simulations are computationally complex Multiple factors affect its appearance and thus lead to unintuitive control parameters
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Structural Modeling of Flames for a Production Environment Eric Hielscher CS 777
Reasons not to use a simulator • Numerical simulations are computationally complex • Multiple factors affect its appearance and thus lead to unintuitive control parameters • Chaotic – small changes in initial conditions lead to dramatically different results and thus iterative methods are difficult
So… we cheat • Instead of simulating real fire, we can use this paper’s method of breaking down how flames look into various things that “look good” even though they aren’t necessarily correct
System Components • B-spline models flame’s structure • A profile is used to create a volume to represent the oxidization region • A flame image is sampled and mapped to the spline • Top portion of flame can break away • Procedural interface
B-spline – the curve’s spine • First, the user creates a B-spline to model the height of the flame • The B-spline’s control points convect within wind fields • Curve is resampled parametrically to ensure that clustering of control points doesn’t lead to visual artifacts
Flame Profile • A profile of a flame is selected from a library of them or drawn by hand • This profile is rotated to create a volume of revolution in which the flame resides
Flame image sampling • Next, a flame image is sampled and particles are created that match the image’s colors • These particles are then cylindrically mapped to the B-spline
Separation • Periodically, a random function is tested to decide whether the top portion of the flame separates
Procedural Interface Various controls are presented to the user, including: • Flame source image • B-spline modeling • Life span of separated plumes • Wind field controls • Interaction with other objects • Flame Spread
What I did • Created B-spline • Created volume from profile curve • Sampled flame image • Tried to cylindrically map particles to B-spline
Some shots A screenshot of a flame A source flame image
What was hard • Paper assumed lots of background knowledge and resources • Some of that background was hard to find, other parts were too large/difficult to implement given the timeframe • It never seemed to look right