Color tips:
• Using a low setting on the Color Randomizer,
you can retain the overall color tone of your effect, while still adding a
bit of variety for greater realism.
• Color Randomizer settings do not affect the
relative changes over time you have set in the Color Gradient. The first
control point color will be randomized, and the relative change between
its color and that of the second control point will be retained. For
example, if you set the Color Gradient to transition from red to light
red, and the randomizer assigns a particle a purple color, that particle
will transition from purple to light purple.
Opacity Randomizer
Basically works the same as the Color
Randomizer, but for the opacity. Opacity Randomizer settings do not affect the relative changes over time you have set in the
Opacity Gradient. The opacity of the first control point will be
randomized, and the relative change between each subsequent control point
will be retained.
Real flames have a fairly large variety in their opacity, so we can
set the Opacity Randomizer fairly high. I used a setting of 0.54, but you
might be able to higher if you want.
Speed Curve
The Speed Curve intially
appears as a straight line. Similar to the gradients for color and
opacity, it represents the lifetime of the particle, from left to
right.
Click on the curve to open its editing widget.
You should be familiar with the control point concept now, so you will
notice that this curve basically edits the same way as the color and
opacity gradients.
Click anywhere in the curve to create a new
Control Point, then drag the Value Gradient slider to set
the speed for that point. You can have up to 20 control points in the
Speed Curve. The speed Value is in pixels per frame.
For this particular effect, we want our flames to continue at a
consistant speed, until the very end of their lives, where we will speed
them up a bit to give them a bit of a snap. This will make the fire more
active and energetic. Set the first Control Point to Value 1.8690,
Location 0%. Now click to add another Control Point, and set it to Value
2.8030, Location 95%. Now add a third, drag it all the way to the end, at
Location 100% and set its Value to 7.4750.
A fire of this
size uses a lot of oxygen. As it burns the oxygen inside the building, it
begins to choke itself, so it grabs at the oxygen outside. As the air
outside is heated by the fire, it rises. These processes are what makes
the fire reach up and outward so quicky, as opposed to a small campfire,
which has plenty of oxygen, and burns at a slower, more lazy pace.
Speed Randomizer
Paired with the Speed Curve you have the Speed Randomizer, which makes the initial particle speed
more variable. Each particle will still follow the speed curve, based on
its individual starting speed.
Flames move at widely varying speeds, so keep the Speed Randomizer set
high. 0.61 at least, you may want to go higher.
Size Curve
Works the same as the Speed Curve but affects
the size of the individual particles. Up to 20 Control Points can be set
in the Size Curve, to alter the size of an individual
particle over the course of its life.
Use the Value Gradient slider
to set the size value for each control point. The size value is a
percentage of a full-size (512x512 pixel) texture. So at 25% each particle
texture will register at 128x128 pixels on your footage.
We don’t need our flame size to change much, so we will leave the
curve as a straight line. One control point, Value 0.2000, Location 0%, is
all we need.
Size Randomizer
The Size Randomizer sets the
randomness of the particles at the start of their life. Each particle will
still grow or shrink according to the relative settings in the speed
Curve.
A wide variety in the size of our flames is a good thing, so use a
setting of 0.61 on the Size Randomizer.
