As of Cinema 4D 2025.1, it is also possible to attach custom properties to the particles, which can then be queried again in Conditions, in Math or Data Mapper modifiers, for example, or offset against other properties of the particles. The Follow Spline modifier offers four properties for saving.

To activate the corresponding storage, activate the option to the left of its name and enter the name of the user particle property that you have created via the Scene Presets in the text field behind it. Alternatively, you will also find a drop-down menu behind each name field, which you can use to call up a list of the user variables that have already been created. There you can also call up the corresponding variable directly, which is then automatically entered in the name field.

You can find out more about creating individual variables for particle properties in the section on Particle Presets within the Scene Presets.

Inside Effect Radius

Here you get a bool value for each particle, whether it is in the area of influence of a spline (true) or not (false).

Distance

Here you get the shortest distance between each particle and the spline as a floating point value. If a particle is outside the spline's area of influence, the effect radius is output.

Segment Index

Here you receive the index of the spline segment that influences the particle as an integer value. If a particle is outside the effect radius, the value -1 is output here.

T Value

A value between 0 and 1 is output here, indicating the current position of each particle along the spline. The value 0 corresponds to the start and the value 1 to the end of the spline.