vector $dissolve = ffd1LatticeParticleShape.worldPosition;
float $expanse = ffd1LatticeParticleShape.expanse;
float $size = ffd1LatticeParticleShape.size;
if ($dissolve.y < $size)
{
ffd1LatticeParticleShape.velocity = unit(ffd1LatticeParticleShape.worldPosition - <<0,0,0>>)*$expanse;
}