These settings define how particles should roll over a surface or how they should squash and stretch.
The node offers two modes, which you set here:
Enable Roll so that particles will roll according to their size and velocity. The Axis values define the axis about which the rolling takes place.
Enabling the Direction Of Travel mode means that particles will be scaled along their direction of travel, in which case Stretch controls the amount of stretching.
Controls how long, in seconds, it takes for the particles to fully adopt the new rolling setting. The higher this value, the slower the transition. This setting can help you to achieve a smooth, gradual change rather than an abrupt, unnatural one.
If Type is set to Roll, these Axis values define the axis about which the particles will be rotated.
The Source value defines which axis will be used for the rolling. If the Invert option is enabled, the chosen axis is inverted to give the negative direction of the chosen axis. For example, if the option is enabled and Source is set to Z, the negative Z axis will be used.
This value is used as a factor for stretching the particles along their direction of travel. The effect depends on the speed of the particles. Using a value of 0.1 will stretch the particles 10 times their usual length, whereas a value of 0 leaves them unchanged.
Additional input ports:
A Boole value of True switches the node on; a value of False switches it off.
Since the node’s parameters can be keyframe animated, by default the Cinema 4D time is used internally to ensure that the values are interpolated correctly. However, you can pass your own time value to this port. This should be of the data type Time, which is a Real number in the simplest case. If no value is passed, Cinema 4D’s time is used.
Connect this port to the stream of particles that you want to be rolled, such as to the Particle output port of a PPass node.