SpeedSix.Fire   (Discreet Fluidz Raptor)


PURPOSE

Simulates flames in two dimensions using a fluid flow approach (a flame is basically a hot fluid - so hot it glows). The flames are driven primarily by buoyancy when there is gravity around, hot air (which is less dense than cold air) gets pushed up as the cold air sinks. The simulation deals with temperature and density. You can map the different temperatures to colours of your choice.

firea.jpg fireb.jpg


INPUT CLIPS

fireH1.jpg Example : Fuel

 1: Fuel : Specifies the location and relative temperature of heat sources Black is cold and white is hot. The heat from the heat sources in each frame of this clip gets added in to the simulation at each frame (so heat builds up around the sources). This heat is the main driving force for the simulation so it is well worth experimenting with the input clip to see how it affects the generated fire. It is highly recommended that you work through the Fire tutorials available on the Speedsix web site.

fireH2.jpg Example : BackGround

 2: BackGround : The simulated flames will be composited over this clip.

fireH3.jpg Example : Barrier

 3: Barrier : Barrier clip. Lets you specify where there are solid objects that the flame will flow around. White denotes the presence of an object. Please note that at a given point there is either part of a solid object or there isn't. The resolution at which "objects" are defined is the resolution of the velocity simulation grid. This is independent of the image resolution being used and is set to 128 x 128. This will inevitably give rise to "jagged" edges around solid objects unless they align perfectly with the grid. A way of dealing with these is to composite full resolution versions of the solid objects over the result.


Fire   CONTROL PAGE

Restart  (Pushbutton)
     Restarts the flame simulation. Please note that this is a physical simulation, the whole point of which is that it evolves over time. It isn't possible to independently calculate frames at random. You must render a complete sequence in order from start to end. This makes it unsuitable for use in some background rendering systems.

PreMultiplyForeground  (Checkbox  Default: Off)
     Have the colours in the foreground fire premultiplied by the fire density before compositing. The simulated density usually makes a very effective alpha channel.

SmokeFader  (Number  Min: 0.0, Max: 1.0, Default: 0.2)
     Reduces density with time. This has a visible effect mostly in the older and colder regions - which can appear like smoke with a suitable choice of colours. So it fades out the smokier regions with time. The higher this value the more quickly things fade away.

Cold Transparency  (Number  Min: 0.0, Max: 21.0, Default: 0.0)
     This normalized gas density in the simulation will be fully transparent when the flame is composited over the background.

Hot Transparency  (Number  Min: 0.0, Max: 21.0, Default: 1.0)
     This normalized gas density in the simulation will be fully opaque when the flame is composited over the background.

Smoothness  (Number  Min: 5, Max: 50, Default: 5)
     Increasing this will reduce the "scalloping" effects that can sometimes be see when very thin, hot, regions are moving quickly. It will, however, make the simulation slower.

Speed  (Number  Min: 0.1, Max: 10.0, Default: 1.0)
     Relative length of the simulation time step between frames. To speed up the motion make this bigger. To slow it down, make it smaller. Best to keep it near 1.0 usually.

Flicker  (Number  Min: 0.0, Max: 10.0, Default: 0.5)
     Increasing this will have the visual effect of making the flames flicker and swirl more DLPage PageOne

SmokeWeight  (Number  Min: 0.0, Max: 10.0, Default: 0.0)
     Relative density of the gas for a fixed temperature. The bigger this is the faster cold gas (i.e. smoke) will fall.

FlameHeight  (Number  Min: 0.0, Max: 10.0, Default: 1.0)
     How quickly the density falls with increasing temperature. The bigger this is, the more quickly the flames will tend to rise. It will also tend to stretch the flames making them thinner.

TempDiss  (Number  Min: 0.0, Max: 1.0, Default: 0.5)
     Temperature dissipation rate. How quickly heat is lost. The bigger this is, the quicker hot gas will cool.

FuelAmount  (Number  Min: 0.0, Max: 1.0, Default: 1.0)
     We feed the fire by adding in the heat from the Fuel Clip to add to the temperature and density of the gas. This control sets how hot the Fuel Clip is. As this is increased, a given grey level represents a higher temperature and density.

Output Matte  (Checkbox  Default: Off)
     Output the alpha channel rather than the full colour image.

Use Barriers  (Checkbox  Default: Off)
     Use the Barrier Clip to define solid objects around which the flames should flow. White denotes the presence of an object. It is strongly recommended that to get anti-aliased flame edges near the solid objects, images of those objects should be composited over the output flame image.

BoundaryLayer  (List Box  Options: Slippery | Rough | Sticky, Default: Slippery)
Barrier object surface characteristics which determine how the flames flow over a surface.
Demos  (List Box  Options: Base | More Smoke | Wilder | Calm Smoke | Extreme | Bold Smoke | Smooth Dramatic | Lapping Fast | Lapping Slow | Smokey, Default: Base)
Select a preset to get you going. The simulation is controlled by a large number parameters, many of which interact. Starting from a preset will help to get appropriate results more quickly.

WandV   CONTROL PAGE

Restart  (Pushbutton)
     Restarts the flame simulation. Please note that this is a physical simulation, the whole point of which is that it evolves over time. It isn't possible to independently calculate frames at random. You must render a complete sequence in order from start to end. This makes it unsuitable for use in some background rendering systems.

Wind 1 Local  (Checkbox  Default: On)
     Make Wind 1 local. It will die away over the distance from Start to End.

Use Wind 1  (Checkbox  Default: Off)
     Turn on-off the first wind force. Values set will not be lost when turned off, only ignored. Wind forces can be used to blow the flames about.

Wind 1 Start  (Position  Default: 0.0,0.0)
     Position of the start of Wind 1.

Wind 1 End  (Position  Default: 0.5,0.5)
     Position of the end of Wind 1.

Wind 1 Strength  (Number  Min: 0.0, Max: 1.0, Default: 0.05)
     The strength of Wind 1.

Wind 1 Tight  (Number  Min: 0.0, Max: 200.0, Default: 1.0)
     The directional tightness of Wind 1.

Use Vortex 1  (Checkbox  Default: Off)
     Turn on-off the first vortex force. Values set will not be lost when turned off, only ignored. A vortex force will make the gas swirl locally. They are rarely useful for flames.

Vortex 1 Center  (Position  Default: 0.333 0.333)
     Position of the center of Vortex 1.

Vortex 1 Radius  (Number  Min: 0.001, Max: 1.0, Default: 0.1)
     The radius of Vortex 1.

Vortex 1 Strength  (Number  Min: -1.0, Max: 1.0, Default: 0.1)
     The strength of Vortex 1.


Colour   CONTROL PAGE

Restart  (Pushbutton)
     Restarts the flame simulation. Please note that this is a physical simulation, the whole point of which is that it evolves over time. It isn't possible to independently calculate frames at random. You must render a complete sequence in order from start to end. This makes it unsuitable for use in some background rendering systems.

AdjustColoursOnly  (Checkbox  Default: Off)
     Adjust only colours. Do not advance the timestep. Note: This will be automatically turned off when Restart is called. This lets you control the colour of the flame (based on its temperature) without affecting its development and motion.

HotBase  (Number  Min: 0.0, Max: 1.0, Default: 0.0)
     See ColdBase.

ColdBase  (Number  Min: 0.0, Max: 10.0, Default: 1.0)
     HotBase and ColdBase map the range of the internal "image" used to repesent the temperature to the range 0.0 to 1.0. You can use this to stretch out a small internal temperature range to a large variation in flame colour or, conversely, compress a large internal temperature range to a small colour range. The value entered for ColdBase is transformed to 0.0 for the value used as input to the temperature to colour mapping process. The value entered for HotBase is transformed to 1.0. The colour map you specify (see below) is defined in terms of mapping this 0.0 to 1.0 range to specific colours. We will refer to the 0.0 to 1.0 range as the normalized temperature below. This can be used to control whether you have flames without smoke or smoke without flames.

Cold Colour  (Colour Box  Default: R: 0, G: 0, B: 0, A: 65535)
     The colour that will be used for the normalized temperature set in the Cold control.

Warm Colour  (Colour Box  Default: R: 8320, G: 2816, B: 2048, A: 65535)
     The colour that will be used for the normalized temperature set in the Warm control.

Warmer Colour  (Colour Box  Default: R: 65535, G: 100, B: 100, A: 65535)
     The colour that will be used for the normalized temperature set in the Warmer control.

Hot Colour  (Colour Box  Default: R: 65535, G: 32214, B: 100, A: 65535)
     The colour that will be used for the normalized temperature set in the Hot control.

Hotter Colour  (Colour Box  Default: R: 65535, G: 65535, B: 100, A: 65535)
     The colour that will be used for the normalized temperature set in the Hotter control.

Hottest Colour  (Colour Box  Default: R: 65535, G: 65535, B: 65535, A: 65535)
     The colour that will be used for the normalized temperature set in the Hottest control.

Cold  (Number  Min: 0.0, Max: 1.0, Default: 0.0)
     The normalized temperature corresponding the the Cold Colour.

Warm  (Number  Min: 0.0, Max: 1.0, Default: 0.2)
     The normalized temperature corresponding the the Warm Colour.

Warmer  (Number  Min: 0.0, Max: 1.0, Default: 0.4)
     The normalized temperature corresponding the the Warmer Colour.

Hot  (Number  Min: 0.0, Max: 1.0, Default: 0.6)
     The normalized temperature corresponding the the Hot Colour.

Hotter  (Number  Min: 0.0, Max: 1.0, Default: 0.8)
     The normalized temperature corresponding the the Hotter Colour.

Hottest  (Number  Min: 0.0, Max: 1.0, Default: 1.0)
     The normalized temperature corresponding the the Hottest Colour.

Index