Action: Change Sprites
This action will let you change the object generated by a Sprite object, or the material applied to the sprite. It can either affect particles directly, or act by changing a Sprite 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 sprite associated with the particle(s) affected by the Action. It does NOT require a Sprite modifier. This lets you change the sprite or its material 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 Sprite 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 Sprite 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.
If unchecked, this will cause the generator to stop generating sprites for the affected particle.
Change Sprite and Sprite Type
If the 'Change Sprite' button is checked, you can use the 'Sprite Type' drop-down to select which object is generated by the Sprite object. So for example, you could use this to change spheres to lights.
Note: if you change the sprite type, make sure you have changed any parameters in the Sprite object to the ones you want for the new type before you use this action to change the sprite.
Change Material and Material Index
If the 'Change Material' button is checked, you can use the 'Material Index' field to select which material is applied to objects generated by the Sprite object. The index refers to the Textures list in the Textures tab of the Sprite object. It is up to you to make sure that the index refers to a valid material. For example, if you specify an index of 2, and there is only one material in the 'Textures' list of the Sprite object, no material will be applied to the sprite.
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.