DSpline Daemon
The "DSpline" daemon is the perfect choice if you want to make particles following a given path.
Start with the spline, e.g. one of Cinema 4D's native types like "Helix", or a hand-drawn spline.
Add a "DSpline" daemon and drag the spline to Daemon Spline > Spline Object.
The viewport gizmo has the spline's shape and red circles, indicating the daemon's control circles.
The circles around the central points represent the area (or better: volume) where the daemon's radial forces are active.
A "DSpline" daemon with default and additional control circles.
In many cases the number of control circles is not sufficient, because the distance between them is too big: some particles might not be dragged from one circle to another. To fix this, add new circles:
Go to Emission > Control and press "Add Control Circle" or in the menu Cinema 4D > RealFlow > Spline Control Circle .
A new control circle appears.
Repeat this process until you have enough circles.
Of course, an emitter is required: the emitter can be placed anywhere on the spline, but please make sure that it is placed inside a control circle. Otherwise some particles will not be attracted, because they are out of scope. Ideally, emission direction is aligned with the spline.
Adjusting Forces
It is possible to adjust each control circle's forces individually under Daemon Spline > Control > Axial | Radial | Vortex. If you want to change forces globally for all circles use the "Strength" parameters:
"Offset" in which position the control circle is located (0 means the begin of the spline and 1 end of the spline).
"Vortex" adds a clockwise (positive values) or counter clockwise (negative values) twist to the particles. The particles might leave their path with high settings, but you will also get a more turbulent fluid.
"Axial" attracts (positive values) particles towards the spline or repels (negative values) them. This way it is possible to create a thinner or thicker particle stream.
"Radial" moves the particles from one control circle to another. Particles outside the circles will not be attracted and leave the path.
"Radius" The circle scope is adjusted with "Radius" or the gizmo handles.
A "DSpline" daemon with a "Sphere" emitter: default forces (left), adjusted forces and a "Drag" daemon (right).
Supporting Daemons
Sometimes it can be difficult to adjust the fluid's velocity or get enough turbulence:
A → "Drag" daemon decelerates the particles. This daemon is very sensitive and you should start with moderate values between 0.1 and 0.5.
Add bounded → "Noise Field" daemons for more turbulence and a vivid fluid simulation. Normally, the daemons are placed along the control circles.
The → "Sheeter" daemon helps to fill holes inside the fluid and prevents the particles from being torn apart.
The → "k Isolated" daemon removes stray particles.
With → "k Age" it is possible to delete particles after a certain time.