5D.Smoke

PURPOSE
Simulates smoke. The smoke is created within an area chosen by the user. You can control where the smoke is born, the qualities of the atmosphere it travels through, the strength and direction of gravity, and a wind force. In many cases, these can be controlled by positioning overlay icons on the image display. You can also confine the birth of smoke to only occur within non-black areas of a matte clip.

INPUT CLIPS
Background: the clip to draw the smoke on.
Birth Clip: the smoke can optionally be created only within areas in this clip which are not black. This lets you restrict the source of smoke to, say, a candle.

Tips:

Smoke is a time based effect; the characteristics a particle is born with, will evolve over time (every frame generated) to create the effect.

Jumping to a random frame will not show you the same result as when the sequence is generated sequentially.

Each particle is created with certain birth characteristics. On the frame they are born they are given:

lifetime
fadeout factor
an initial velocity and variance
a birth position ( the birth generation line )
a color (RGB) with variations (Color variance & Mono variance)

These factors are only changed by other forces acting on them.

animating the color will not change all the particles, only the particles that are born at that frame; but the color may fade over time depending on the Extinction factor.

the initial velocity causes the particles to move, but then gravity, wind; swirling, friction etc take effect.

Birth Limits: Particles can be born in an arbitrarily shaped region controlled by the intensity levels in the birth clip (which are 128 or greater) and the birth generation line (which should cross this region) if Use Matte Limits is on. If your control clip is not bright enough or your birth creation line misses the required area in the control clip, particle generation is stopped. Otherwise you would be forever trying to create a particle while the conditions for birth are not suitable.

Smoke relies on a large number of very small and faint particles to draw the representation of smoke. It can take longer than most particle systems to generate.

TIME EDITOR CONTROLS

CREATION
Preroll Frames (Min: 1 Max: 1000 Default: 50)
How many frames to run the particle system before generating the first frame of the output clip if Do Preroll is selected.

Density (Min: 0.0 Max: 10000.0 Default: 1800.0)
Average number of smoke particles created per frame.

Extinction (Min: 1.0 Max: 1000.0 Default 180.0)
Number of frames over which a particle of smoke will fade away.

To Live (Min: 1.0 Max: 1000.0 Default 80.0)
Number of frames of life after which a particle of smoke will be destroyed.

POSITION
Radius (Min: 0.0 Max: 500.0 Default: 0.4)
Distance from the smoke creation line within which smoke will be created.

XY Left (Default: center)
XY Right (Default: center)
The ends of of a line along which smoke will be created.

SIZE
Puff Radius (Min: 0.0 Max: 20.0 Default: 2.0)
The maximum size a puff of smoke can be when the style Puff is chosen.

Puff Variance (Min: 0.0 Max: 100.0 Default: 100.0)
The posibiltiy of puffs of different being created when the style Puff is chosen.

FORCES

HEAT
btu (Min: -80.0 Max: 80.0 Default: 8.0)
The initial speed given to a smoke particle when created. (btu = British Thermal Units) The direction is always in the direction of gravity.

btu Variance (Min: -100.0 Max: 100.0 Default: 100.0)
Size of random variations in initial speed of a smoke particle. The direction is always in the direction of gravity.

GRAVITY
Strength (Min: 0.0 Max: 1000.0 Default: 0.1)
Scales the strength of the gravitational force.

Angle (Min : 0.0 Max: 360.0 Default: 270.0)
Controls the angle at which gravity acts, measured in degrees clockwise from due East. The default is towards the bottom of the image.

WIND
Speed (Min: 0.0 Max: 100.0 Default: 0.0)
The speed of the wind.

XY Target (Default: pointing to center)
The point on the image at which the wind is blowing.

Spread (Min: 0 Max: 180.0 Default: 90.0)
Angle (in degrees) of a cone within which the wind blows. The wind has zero strength outside this cone, and reaches full strength inside a cone that is 10% smaller.

XY Source (Default: bottom left)
The point on the image from which the wind is blowing.

SWIRL
Density (Min: 0.0 Max: 100.0 Default: 28.8)
Number of turbulent bumps in the atmosphere across the frame. The smoke can bump into these, causing them to swirl.

Amplitude (Min: 0.0 Max: 100.0 Default: 0.0)
Strength of the turbulent bumps in the atmosphere.

To Maximum (Min: 0.0 Max: 500.0 Default: 0.0)
The swirling of the atmosphere builds up from zero to its specified amplitude over this number of frames.

Friction (Min: 0.0 Max: 100.0 Default: 1.0)
Controls the frictional force of the atmosphere on the drops as a percentage of the drops velocity lost per frame. Slows the smoke down and helps it swirl more densely.

SMOKE COLOUR
Red/Green/Blue (Default: light greyish blue)
The color given to the smoke particles when they are created.

Color Variance (Min: 0.0 Max: 100.0 Default: 0.0)
Random variation in the color of the smoke particles.

Monochrome Variance (Min: 0.0 Max: 100.0 Default: 0.0)
Random variation in the brightness / density of the smoke particles.

Intensity (Min: 0.0 Max: 400.0 Default: 62.5)
Initial intensity (or brightness) of a smoke particle.

Condensation (Min: 0.0 Max: 100.0 Default: 0.0)
When born, a smoke particle can be transparent. This controls how quickly it becomes denser and more visible.

PI CONTROLS

restart
Restart the rain simulation, destroying all current raindrops first.

preroll
Run the particle system for the specified number of pre-roll frames before generating the first frame of the output clip.

RENDER PREROLL
This MUST be turned ON prior to rendering a sequence if you need the preroll effect. Rendering starts a completely new rainstorm; it cannot continue from where you currently are.

SIZE STYLE
points/streaks/puffs
Select the desired smoke particle shape.
Hint: choose Streak to checkout the speed and direction of movement.

CLIP CONTROL
birth limits (Default: Off)
Off: uses only the position 'lozenge' to generate the rain particles.
On: uses the Birth clip to generate rain only if covered by the position lozenge.

RENDERING
colour & density/colour/density (Default: colour & density)
These options affects how the smoke particles composite with one another and with the background image and may have a great effect on the final appearance. For smoke, using Density is usually best.

DEMOS
wisp: set smoke parameters for wispy (snuffed candle/cigarette) style of smoke.
steam: set smoke parameters for a steam effect.
puff: set smoke parameters for a steam train smoke trail effect.
dry ice: set smoke parameters for a dry ice effect.

5D.Smoke

Index