Decay
This page describes the Decay layer in Cinema 4D's Field system. It makes Field changes fade out over time — effects linger and decay after the Field has moved on, like cooling traces.
The Decay Layer is similar to the Delay Layer, as it influences the temporal course of changes (due to fields/modifier layers arranged before it in the field list; which also includes color changes, for example) and can therefore also have an effect outside a field influence area.
If, for example, a clone moves from one animation frame from Y = 0 to the next to Y = 100 and then to Y = 0 again, i.e. performs a sudden movement, the Decay field ensures that this lightning-like movement is transformed into a slow decaying movement (the speed can be adjusted).
To describe it a little more precisely (and to distinguish it from the Delay Layer): it is a lightning-like increase in value with a delayed decay (or vice versa).
Example
In this example, spherical fields leave their footprints on a vertex map. The first half of the video shows the effect strength 100%, which maintains the effect over time (this could be used to create footprints of a walking character in the snow, for example).
