User Guide

Working with Models and Model Resources 479
Mesh generator commands
Use these commands to work with mesh primitives:
Particle system properties
Particle systems are unique among model resources in that they include animation by default.
Particle systems, whose type is #particle, can have an almost infinite variety of appearances,
simulating fire, smoke, running water, and other streaming or bursting effects.
Use these properties to work with particle systems:
Command Description Returns
build() Builds the mesh according to the current property values.
(The mesh construction properties specified in the previous
table have no effect until
build() is called.)
Generates a Lingo error if any properties specify an
invalid list.
Nothing
generateNormals
(
style)
Generates a new normal for every vertex in every triangle.
The
style parameter can be #flat, so that each triangle
is clearly delineated, or
#smooth. The command assumes
that all triangles were specified in a clockwise order.
Nothing
Property Access Description Value Range
lifetime Get and set Lifetime of all particles emitted, in milliseconds. Positive integer. The
default is
10.000 ms.
colorRange.
end
Get and set Color value of a particle at the end of its life. Any color value. The
default is
rgb(255,
255, 255)
.
colorRange.
start
Get and set Color value of a particle at the start of its life. Any color value. The
default is
rgb(255,
255, 255)
.
tweenMode Get and set The variation of a particle’s color throughout its
life. The change can be based on either velocity
or age.
#velocity:
Alter particle color
between
colorRange.
start
and
colorRange.
end
based on velocity.
#age:
Alter particle color
between
colorRange.start
and
colorRange.end
based on the particle’s
lifetime.
sizeRange.
start
Get and set The size of a particle at the start of its life. Positive integer.
The default is
1.
sizeRange.
end
Get and set Size of a particle at the end of its life. The size is
linearly interpolated between
startSize and
endSize.
Positive integer. The
default is
1.
blendRange.
start
Get and set Opacity of a particle at the start of its life. Any value between
0.0 and 100.0.
blendRange.
end
Get and set Opacity of a particle at the end of its life. Any value between
0.0 and 100.0.