PhysX Force Operator

Force Type - Defines the force magnitude, as affected by particle properties. The standard Force operator applies the same force value to a particle; the force magnitude is affected only by particle speed and position. With the standard Force operator, if two particles have the same position and speed then the same force is applied to these particles.

The PhysX Force operator can also take into consideration other particle properties — their mass and shape — by using the appropriate Force Type option:

• Gravity - The force magnitude is adjusted by particle mass, in direct proportion — the higher the mass, the higher the force — in a way somewhat similar to the gravity effect. The option most closely resembles the standard Force operator. Because force is adjusted proportionally to particle mass, two particles, even with different masses, will travel with the same speed, as in the fabled experiment in which Galileo dropped two different weights off the Leaning Tower of Pisa.

• Surface - The force magnitude is adjusted by particle surface area visible from the direction of the force. This type simulates the effect of wind force.

• Uniform - The force magnitude is applied as is, without any adjustment by particle mass or size. This is like a finite force from an external force. With this force type, if two particles of different sizes have different masses, then the larger particle would accelerate less.

Example 1:  PhysXForce_ForceTypes_01.zip

Example 2:  PhysXForce_ForceTypes_02.zip