Creating Realistic Fires in
EffectsLab & VisionLab Studio, Pg. 7
Blend Mode
Here you can set how the particles are blended
into each other, as well as the underlying layers. Normal means that the colors of your particle effect will not be altered. Add and Screen are designed to be used
with effects which create a light source, such as fire, or some magical
effects.
In reality, the more flames you have, the brighter the fire is going
to get. To realistically simulate this, set the Blend Mode on our flame
effect to Add. This will let our flames composite properly onto each other
when they overlap, and composite properly onto the background. Now you
should have Particle Properties controls which match this:
You now have all of the basic settings for your fire. Go to the last
frame of your effect, and set the Out Point for your clip by pressing 'O'.
Turn off the Preview Emitters in the Canvas menu, and Preview render your
effect (click the RAM button on the Top left of the timeline).
Take a look at your newly-kindled fire.
:)
Now we will use Gravity and some additional keyframing animation to
make the flames move a bit more realistically. You may want to return to
your Preview Emitters before we begin editing once again.
Environment Gravity
You can use Gravity to pull
your particles in a given direction after they are emitted. It can be used
to pull them downward, and thus simulate actual gravity, or you can set it
to pull them sideways, to simulate the effects of wind, for example. Use
the Direction Wheel to set the direction toward which
gravity should pull.
Gravity Strength
The Gravity Strength slider
adjusts the strength of the gravity’s pull. This will determine how
quickly it affects the particles after their emission, and how quickly
they move in the direction gravity is pulling them.
When you have a fire
near a wall, the fire (and smoke) will, in general, automatically hug the
surface of the wall as they rise. Some of the smoke will often wander
about, but the majority of it will stay near the wall surface.
To simulate this behavior, we will use the gravity controls to pull
them upward. Set the Direction Wheel in the Gravity controls to straight
up, or just barely off to the right of straight up. I have it at an
Absolute angle of 0.38.
We want the gravity to pull the flames upward, but not too fast.
Set the Gravity Strength to 0.07. Turning up the gravity too far would
cause the particles to start moving in their new direction too soon after
their creation, and at too great a speed. Keeping it low means that it
will still have an effect, but not until their original momentum has
carried them out of the window.
Another trick that we can now use, with this gravity in place,
will give more movement to our flames. The pull of gravity will keep all
of the flame particles moving in the same general direction, so by varying
the direction of our emitter, with the Direction Wheel in the Particle
Creation settings, we can get a lot more variety in the direction of the
individual particles.
This step will get too involved for me to provide specific data
for each keyframe, so here is the basic procedure. At random intervals on
the timeline, we will alter the direction of the flame emitter. I used
intervals of anywhere from 3 to 35 frames or so, and waved the emitter
back and forth to arbitrary angles ranging roughly from -5 degrees to 90
degrees, Absolute.
Look at the Inferno preset to see more specifically how this
works, if you are unclear. Once you have these keyframes set, your
particles are pretty much finished. Now we just have to place them in the
window. Preview render again, and have a look at your work.
