Details Tab

Collision Eps [0.001..10000000]

This parameter is used for collision detection only.

It defines 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 first 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.

Collision Use Rest Speed / Collision Rest Speed [0..10000000]

When you slide an object over a surface using Dynamics, under some circumstances, the object may start to ‘sink’ through the surface.

The Collision Rest Speed parameter is designed to prevent this sinking from happening. When the Use option is enabled, it will give the sliding object a little push away from the surface (in the direction of the surface’s normal, that is).

To prevent this little push from being added to rebounding objects that are not sliding, the push will be exerted only if the object’s velocity in the direction of the surface is below a certain velocity — this threshold velocity is the Collision Rest Speed.

For an object to rest on a surface, the distance between the object and surface must be less than the Eps distance and the object’s velocity must be less than the Collision Rest Speed. Static drag will then take hold.

A . Collision Use Rest Speed enabled. B. Collision Use Rest Speed disabled. The Rest Speed parameter helps to prevent sliding objects from penetrating the surface they are sliding over.

Particularly with complicated spring-mass systems or soft bodies, an inappropriate integration method can create unexpected behavior. This unusual behavior is possible in all existing dynamics engines.

Also possible are instable states with which no realistic motion can be achieved regardless of the integration settings. Such states can be tackled only by using a new spring arrangement or by adjusting the masses, spring forces and damping.

Baking

Baking Frame Step [1..100]

Here you determine how many keyframes will be created when you bake the motion in the Timeline. The most accurate setting here is 1, which will cause a keyframe to be created for each frame. If you intend to edit the animation, you should choose the highest value possible that does not lead to errors with the motion.

Baking Layer

CINEMA 4D’s timeline has eight layers. For this parameter, select the layer in which the baked track will be placed when you bake the motion in the Timeline. For details on the Timeline’s layers, please consult your CINEMA 4D Reference Manual.