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176 Chapter 11: Space Warps and Particle Systems
Shape
Shape Operator
Particle View (page 2–125) >ClickShapeinaneventoradd
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 article system. You can use
it to specify particles in the shape of pyramids,
cubes, spheres, or vertices, as well a s particle size.
Note: All pr imitive particles created with Shape
have pivot poin ts in their geometric centers.
See also
Shape Instance O perator (page 2–178)
Shape Facing Operator (page 2–176)
Shape Mark Operator (page 2–183)
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 scr ipt operators.
•
Tetra—These tetrahedron-shaped par ticles
haveafourtriangularsides. Havingonly
four p olygons, 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 particles. The sphere
has the most polygons of the rendering particle
shapes, and its orientation isn’t obvious.
Size—Sets the overall size of the particles in system
units. Default=10.0
Setting Size=0 makes the par ticles invisible.
Scale—Tur n on to set the size of the particles as a
percentage of the Size value. Use the numeric field
to set the Scale p ercentage value. Default=100.
Scale is animatable, while Size is not. A lso, turning
onScalecreatesthescaledatathatanyScale
operators fur ther on in the flow can work with.
Shape Facing Operator
Partic le View (page 2–125) > 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 particle as
a rectangle that always faces a par t icular object,
camera, or d irection. For effects like smoke, fire,
water, bubbles, or snowflakes, use Shape Facing
w ith a material containing appropriate opacity and
diffuse map s.
By default, the particles’ top and bottom sides are
parallel to the horizontal plane. T he Orientation
setting lets you change this default alignment.
Note: FortheShapeFacingoperatortobeableto
calculate the particle orientation, it must know the
current particle position. For this reason, always
placetheShapeFacingoperatorbelow aPosition
operator in an event.
See also
Shape Operator (page 2–176)
Shape Instance Operator (page 2–178)
Shape Mark Operator (page 2–183)