SHREDDER EFFECT

Shredder (Explosion) effect:

Example Project:

100 frame animation.
Default size primative sphere at position (0, 0, 0).
Ground object at position (0, 0, -100.0).
Shredder applied to the Sphere from frame 2 to frame 100.

This example will give you a starting point when working with Shredder.
To speed up the animation so that all the particles stop moving, increase
the "End Time" to something like 2.

Overview:

Shredder does an explode that breaks up an object into random
shaped/sized
particles.  The effect can also explode an object while keeping subgroups
intact or, in the case of a grouped object made of many, smaller parts, it
can keep the whole objects intact.

The effect tries to use real-world numbers (seconds and meters) instead of
the usual frames and units measurements.  Because of this, you have to tell
Shredder how many units are in a meter and how many seconds are
represented
in the included frames.

Textures that are properly tacked to an object (State objects with shape
and texture data saved as well as lock states in all the textures) will
remain tacked during the explode.

Shredder is a very complex effect, and shredding an object with a lot of
faces will be slow compared to Imagine's other effects.  Using subgroups
or keeping objects intact is much faster than shredding up an object La
Machine style.

Shredder F/X Info

The first part of the Sredder requester asks the following info:

o Whole Objects as Parts (Grouped Object)
o Use Defined Subgroups as parts
o La Machine
Maximum Number of Triangles in Group []
Bounding Subgroup []

This Controls how the object(s) are shredded.  "Whole Objects as Parts"
keep
entire objects intact - like you may use to explode a grouped object while
keep the individual objects intact.  By selecting this, you can also make a
single object bounce on the ground like a rubber ball.  "Use Defined
Subgroups" lets you absolutely control the size and shape of the pieces that
fly off the shredded object.  By defining subgroups on the object you can do
something like blowing up a sphere with a logo pasted on it while keeping
the chunk of the object with the logo intact.  "La Machine" is where
Shredder gets its name - it totally shreds an object into random shaped and
sized pieces.  The size of the pieces is controlled with the "Maximum
Number of Triangles" parameter.  The "Bounding Subgroup" can be use to
restrict the explosion to a specific part of the object.  Try the example
project with "Whole Objects" selected to see the sphere bounce.

When Shredder shreds an object in "La Machine" mode, it selects groups of
adjacent faces by doing a random walk over the surface of the object.  This
produces shapes that tend to wander across the surface instead of looking
like clumps of faces all grouped together.

The Timing of the effect is controlled in the following seciton of the
requester data:

Start / End Time (seconds) [] []
Explosion Timing Delay (%) []
"Hold at" Frame Number []

The start and end time parameters control the speed and direction of the
animation.  These tell the effect how much real time apparently passes
during the time of the effect.  For example, increasing the end time from
1.0 to 3.0 without changing the number of frames in the effect will triple
the speed that the effect happens at (ie - originally n frames meant 1
second of time, now the same n frames represent 3 seconds of time).  The
start and end times can also be used to reverse the explosion timing (set
the start time to 1.0 and the end time to 0.0).

The "Delay" factor is used to slowly explode the object from the axis
position outward and the "Hold at" number will freeze the explosion at
a certain time.

The data that describes the bouncing of the particles is as follows:

o Bounce Particles
o Flip on Bounce
Ground Z Position (Imagine units) []
o Use Maximal Bounding Sphere
o Use Minimal Bounding Sphere
o Use Average Bounding Sphere
Elasticity Min/Max (%) [] []

Selecting "Bounce Particles" turns the particle bouncing part of the effect
on.  Selecting "Flip on Bounce" will cause the particle rotation to reverse
each time a particle bounces.  Where the particles bounce must be set in
the "Ground Z Position" parameter since the FX knows nothing about the
other objects in Imagine's world.  When particles bounce, they bounce
relative to when their center of mass hits the ground.  By selecting one of
the bounding spheres, you can make the particles  bounce as if their shapes
were actually spherical (they had a radius) instead of just points in space.
The Maximal Bounding sphere will totally enclose all the points in the
particle, the Minimal Sphere is inside all the points, and the average
Sphere has a radius of the average point distance from the canter of mass.
The Elasticity range allows you to control how much bounce the particles
will have.

The particle conditions are set up in the following:

Inital Velocity Range Min/Max   (m/s) [] []
Triangle Rotations Min/Max    (rot/s) [] []
Particle Trajectory Min/Max (degrees) [] []
Final Scaling Factor Range Min/Max    [] []
Gravitational Acceleration    (m/s^2) []

The Initial Velocity values control the initial energy of the explosion,
that is, how far and fast the particles blow away from their original
positions.

When the object explodes, it explodes as if the object's axes are the origin
of the explosion.  The Trajectory adjustment randomly varies the angle that
the particle flies off, relative to the objects axes position.

The Gravitational Acceleration controls how fast the particle will fall to
the ground.  Set this to 0.0 in outer-space scenes to emulate zero gravity.
Watch the sign on this value - negative values make particles fall down,
posative makes them fall up.

Lastly, the following parameters must be set up:

Imagine Units per Meter      []
Random Number Generator Seed []

"Imagine Units per Meter" needs to be set so that you can use real world
values for the velocity and gravity settings.  The Random Seed value is
used to vary all the randomness in the effect (ei - particle shapes, initial
velocities, etc...).