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Table Of Contents
160 FORCE FIELDS
DYNAMICS
DYNAMICS
FORCE FIELDS 161
The Newton eld can be used to
create elliptical paths, making it
suitable for planetary orbits.
Shown above are two rigid bodies that have been placed in a Newton eld. If the
motion is drag-free — like motion in outer space — the bodies will travel along an
elliptical path. This is because the force of attraction will increase as the bodies near
each other. It is this principle of attraction that explains why the planets in our solar
system orbit the sun. The sun itself remains largely unaffected by the pull of the
planets due to its enormous mass. So to simulate planetary orbits, you should use
the Newton eld.
The Newton eld has many other uses besides planetary orbits. In particular, it can
simulate collision detection such as pool balls bouncing off each other. Although
you could alternatively use the collision detection engine, collision via gravity elds
is much faster to process.
To simulate collision detection using a Newton eld, enable the Exclusion option
(Shape tab) and set Falloff to Step (Falloff tab).
Strength
Strength denes the size of the force exerted by the eld. You can enter a positive
value or a negative value. In the case of a Newton eld, a positive value will cause
attraction whereas a negative value will cause repulsion.
The effect of a varying Strength
value on the Axial, Radial and
Newton elds.