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172 Chapter 11: Space Warps and Particle Systems
Shape
Particle View (page 2–121) >ClickShapeinaneventor
add a Shape operator to the particle system and then
select it.
Shape is the default operator for defining the
geometr y used in the p art icle system. You can use
it to specify particles in the shape of pyramids,
cubes, spheres, or ver tices, as well as particle size.
Note: Al l primitive part icles created with Shape
have pivot points in their geometric centers.
See also
Shape Instance Operator (p age 2–174)
Shape Facing Operator (page 2–172)
Shape Mark Operator (page 2–179)
Inter face
Shape—Sets the shape of the particles to
Vertex or one of three geometric primitives.
Default=Pyramid.
•
Vertex—Usethisoptiontocreatenon-rendering
particleswhosesoleattributeistheirlocation.
This can be useful when using script operators.
•
Tetra—These tetrahedron-shaped particles
haveafourtriangularsides. Havingonly
four polygons, the tetra is the simplest of the
rendering particle shapes.
•
Cube—These box-shaped particles have six
square sides, all the same size.
•
Sphere—Creates spherical part icles. The sphere
has the most polygons of the rendering particle
shapes, and its orientation isn’t obvious.
Size—Sets the overall size of the par ticles in system
units. Default=10.0
Setting Size=0 makes the particles invisible.
Scale—Turn on to set the size of the par ticles as a
percentage of the Size value. Use the numeric field
to set the Scale percentage va lue. Default=100.
Scale is animatable, w hile Size is not. Also, turning
onScalecreatesthescaledatathatanyScale
operators fur ther on in the flow c an work with.
Shape Facing Operator
Particle View (page 2–121) > Click Shape Facing in an
event or add a Shape Facing operator to the particle
system and then select it.
The Shape Facing operator creates each part icle as
a rectangle that always faces a part icular object,
camera, or direction. For effects like smoke, fire,
water, bubbles, or snowflakes, use Shape Facing
w ith a material containing appropriate opacity and
diffuse maps.
By default, the particles’ top and bottom sides are
parallel to the horizontal plane. The Orientation
setting lets you change this default alignment.
Note: FortheShapeFacingoperatortobeableto
calculate the part icle orientation, it must know the
current particle position. For this reason, always
placetheShapeFacingoperator
below a Position
operator in an event.
See also
Shape Operator (page 2–172)
Shape Instance Operator (page 2–174)
Shape Mark Operator (page 2–179)