Motion Control and Surface Interaction Behavior for ICE Particles
 
 
 

You can control particle behavior in many different ways, but the most common ways include controlling the particle's motion and the way in which it interacts with object surfaces.

There are several particle compounds that let you control the particle's behavior. These compounds are fairly complex and complete within themselves, but you can also use them in conjunction with State systems as part of a larger effect. Within a State system, you can choose one of these compounds to create the effect that happens when trigger compound's value is reached: example, new particles can be spawned when they collide with an obstacle.

Most of these behavioral compounds are described in this section, but there are a few others that are described elsewhere:

About ICE Particle Collisions

You can create different types of particle collisions depending on what type of behavior you want to happen upon impact. Collisions are often used to change the particle's behavior in a State system, but you can create collisions without using State compounds.

When particles collide with an obstacle's geometry, the collision geometry type that is used for the obstacles is its actual shape. As well, the particle's size is taken into account upon collision. However, if you're using instanced shapes as the particle geometry, an approximated bounding sphere is created around it: its actual shape is not used.

One thing you may notice when particles collide with objects is that their rotation doesn't change after a collision. That is, if a rotated particle collides with an object, it doesn't change its rotation as might happen in real life (such as with faster rotation or changed rotational direction upon impact).

These are the types of behavior you can make the particles have upon collision with obstacles:

The different collision compounds are based on the Basic Collide node. If you want to create your own collision compounds, you can use this all-purpose node to serve as a base.

Particle Surface Interaction Attributes

There are several particle attributes that are used to define particle surface interactions with obstacles and particles moving toward goals. These attributes are used in several compounds that are described in this section, but you can also use them on their own in an ICE tree by specifying them in the Get Data and Set Data nodes, as described in Using ICE Particle Attributes.

For more information on attributes in general, see ICE Attributes.