[Brian Jones]

another of the presets should get you there – TP Follow Spline – I don’t know how ‘roughly’ that is, it seems to keep initial spacing by default, however, Precision, Point Velocity and Tangent Velocity seems to be the way to get a more approximate follow, you can lower Precision and Tangent and get pretty predictable results. Point Velocity is weirder, below the default 0.1 and it gets less able to follow, between 0.1 and 1 it will ‘focus’ along the length of the spline and at 1 and 1+ it glues all particles to the spline, touchy but interesting

[Brian Jones]

the xpresso node you want is PDeflector but in the Content Browser Presets/Studio/Simulation/Thinking Particles/Interaction/TP Object Collision is a preset to simplify things (or at least give you an example if you want to DIY)

[Brian Jones]

can you post the scene file (without the phone I assume). QMC would likely solve your problems but sometimes artifacts can be minimized (though artifacts that stay are unusual)

[Brian Jones]

the point node in Adam’s xpresso works with poly objects as well as splines, so you just have to feed the pyramid (it has to be editable) as the Object into the Point node (instead of the spline object) and in the Point node set the Point Index to the number of the point you want to follow (be forced to…) the Null’s position

[Brian Jones]

a linear spline in the Thickness/Distance controller is not good visually at that viewing angle, a cubic-ish one looks better.
The different rates at which the short and long spline parts fade can be fixed by changing the spline’s Intermediate Points to Uniform. I did testing on Path.3 as it seems to have most of the structure but makes the test simpler and the file smaller.

11133_linethicknesstest.c4d.zip

[Brian Jones]

yes, Backlight shader in the luminance channel on the plane

[Brian Jones]

the selection should work for all selected clones once the min/max is right as far as I know… can you post the scene?

[Brian Jones]

have to know more about the setup to know but my first thought was this tutorial https://www.thepixellab.net/c4d-tutorial-mograph-selection-deleting-individual-clones

[Brian Jones]

ok, had to change a bunch – really I just set a lot of stuff back to normal values and started fresh-ish. The biggest change I remember is with the bristles – I changed them to Moving Mesh from Automatic (which wouldn’t follow the bend and was a reason things were moving too soon). Oh and made the small particles be dynamic as well rather than colliders – as colliders they just make it a really rough floor which probably doesn’t help. Added colors to be able to visualize better. Changed a bunch of settings, frictions (the help says there is no rolling friction at all in the system so some angular damping is needed). Changed the spheres (large and small) to Density. Lowered segments of the spheres and rotation segments the bristles (but increased the height segments) to make the simulation run a bit faster. I ended up increasing the steps per frame some but still with the current setup ended up with some spheres sticking to the broom but now at least they release on the back stroke. However, it seems to be related to the Bend as when I disable the Bends the spheres don’t stick at all. Perhaps the bristles could be soft bodies and that would fix it (haven’t tested that).

Current setup –11129_broomtest.c4d.zip

[Brian Jones]

I assume you are using the Distance modifier under thickness. What do you have Range set to? I’m guessing you are going to have to set it to Custom and work out what the distances are.