9.0

Table Of Contents

172 SOLVER OBJECT

DYNAMICS

SOLVER OBJECT 173

Details Tab

Here you’ll nd settings that

relate to collision detection

and baking.

Collision Eps (Epsilon)

This parameter is used for collision detection only. It denes a distance in units above

and below the surface in which collision can take place, helping to avoid penetration.

As soon as an object enters this region, the object will rebound.

Here, the dots represent the

nearest point of an object as the

object rebounds off a cuboid.

The rebound will take place as

soon as the point enters the Eps

region.

The Eps parameter is more important that it rst appears. It is especially critical

when fast-moving objects are colliding with each other. In such cases, the objects

will penetrate each other if the Eps value is set too low.

Set the Eps value too high, on the other hand, and objects will rebound before they

should. For example, two pool balls may rebound while they are still 10 cm apart

if the Eps value is too high. Here, a popular technique can help you to obtain more

reliable collisions. It works by making use of a proxy object, using a similar technique

to the proxy collision object described in the chapter on rigid bodies. This time, the

proxy object should be scaled down so that it is smaller than the real object. This will

enable you to use a higher, more reliable, Eps value.