Creating%20Fire

1
Animating Fire
by Kathleen Marty
2
How to create fire?

• Implement the paper Structural Modeling of
  Flames for a Production Environment, by Arnauld
  Lamorlette and Nick Foster.
• Emphasis Total artistic and behavioral control.
• Basis Physics and stochastic models. No
  intention to perfectly model real world.

3
Motivation

• Why not use a numerical simulation to model fire?
• Numerical simulations scale poorly. Increase in
  resolution O(n3) increase in complexity.
• Fire is chaotic. Initial conditions cause drastic
  effects.
• Unintuitive to control under different physical
  circumstances.

4
Essential Model 8 stages
(1) Flame Spine
(2) Wind Field
(3) Flicker / Separate
(4) Profile
(5) Noise
(6) Transform
(7) Render
(8) Procedural Controls
5
What I did Flame spine

• Step 1 Created a B-spline that can interpolate
  through points that move in a wind field.
• Step 2 Windfield modeled thermal bouyancy and
  diffusion. Did not model rotational wind. Solved
  using rk4.
• Step 3 Modeled flame flickering. Flickers when
  reaches a certain height. Did not model flame
  separation.

6
What I did Flame profile

• Step 4 Obtained flame profile by thresholding a
  flame image and reading the boundary.
• Rotated the profile about the center and randomly
  sampled the volume to create particles.
• Step 5 Adding noise to the volumetric samples
  made it look bad. Paper uses Flow Noise
  Perlin.

7
What I did Profile Transformation

• Step 6 Transformed the flame from the profile
  space to corresponding points on the flame spine.
  
• Quaternoins worked perfectly for this step, I
  learned the hard way. (Rotation about an
  arbitrary axis).

8
What I did Rendering

• Step 7 Rendered the flame only by mapping colors
  from original image to particles.
• Did not
• Apply density function to determine
  incandescence.
• Super-sample profile based on camera position
  (flames are view-dependent).
• Do Step 8 flame spread, object interaction,
  smoke generation.

9
Some Results
10
Some Results
11
Getting into Maya

• Plugin Got particles in but lost color mapping.

12
Given more time