8

Collision Test 209
Inthenextstep,you’llseewhathappenswhen
actions in an event are not in the right order.
9. In Event 01, move the Collision test above the
Force operator, and then play the animation.
Quite a few particles leak through the deflector.
This happens because the software first tests
the particles for a collision, and then applies
theGravityforce. Theparticlesthatare
approaching the deflector and are very close
to it are being tested for a collision, which tests
False because they haven’t ac tually struck the
deflector yet. T he software then applies the
gravity, which pushes them past the deflector,
making them no longer eligible for testing for
collision. Generally speaking, it is best to keep
ForceoperatorsaboveCollisiontestsineach
eventtoensurethatparticlesdon’tleakthrough
the deflector.
Interfa ce
The user interface appears in the parameters panel,
on the right side of the P article View dialog.
Deflectors group
This group displays the deflectors currently in
effect, and let you add and remove deflectors.
[list]—Shows the deflectors t hat apply to this
operator. If more than three deflectors apply, a
scroll bar appears at the r ight side of the l ist.
If you delete a listed space warp from the scene,
itsnameisreplacedinthelistbytheentry
“<deleted>”.