Action: Change Lights
This action will let you vary the parameters of lights generated by a Sprite object. It can either affect particles directly, or act by changing a Light modifier in the scene.
The Action's interface looks like this:
This sets the operation mode of the Action. There are two options:
The Action will directly alter the parameters of the light. It does NOT require a Light modifier. This lets you change the lights at a precise point without having to work indirectly through a modifier, which can be a little convoluted for such a simple alteration.
In this case the Action will let you control the operation of a Light modifier in the scene.
Control Modifier Mode
This field is only available if you choose 'Control Modifier' in the Mode setting.
This field accepts a Light modifier which you drag into the field from the Object Manager. Without a linked modifier, you cannot access any of the other parameters and the Action will have no effect. In addition, in the modifier's interface the Mode parameter MUST be set to 'Action-Controlled'. If it is set to 'Independent' the modifier will simply work on its own like any of the standard Cinema 4D modifiers and the Action will have no effect on it.
Effect on Particle
This drop-down menu has two modes:
Modifier Will Affect Particle
In this mode the modifier will start to influence the particular particle which is affected by this Action. Once the particle is influenced by a modifier, that influence will continue until the effect is turned off (e.g. by another Action).
Note that whether the modifier actually has any effect on the particle will depend on the modifier's parameters and especially on its falloff. Even if the modifier is set to effect a particle, it may have no effect on it if the particle never enters the field of effect of the modifier.
Modifier Will NOT Affect Particle
In this mode, the modifier's influence on the particle will be turned off and the modifier will never affect the particle, unless it is turned back on again (e.g. by another Action).
Direct Change Mode
These are the parameters which can be changed in 'Direct Change' mode.
Change Illumination and Change Visible Light
To change either of the parameters in these two sections, you must first check the relevant button. If a button is left unchecked, those parameters will not be changed by the Action.
The amount of illumination produced by the light. Note that the light will only illuminate if 'No Illumination' is unchecked in the Sprite object.
The brightness of a visible light.
Drag any particle group objects into this list. If there is one or more groups in the list, only those particles which are in those groups will be affected by the action. But if there are no groups, all particles will be affected by the action.