Trying to understand how pop forces work when there are multiple nodes used. My assumption was that they are additive, like when using Noise and an Add node in a Point VOP on P. But due to the Air Resistance param they don't seem to work like that and fight against eachother. Unless I'm missing something?

Eg if I have a POP velocity in a FLIP sim then add a POP Wind node for layering in some noise (0,0,0 for wind velocity) the POP velocity is reduced from what it was and I either have to reduce the Air Resistance of the wind, or scale up the POP Velocity force. That gets problematic when directing a fluid sim since when you add a new force it also reduces the effect all the others.

Is there some way to make the forces combine without overwriting eachother so it's easier to control?

If you want a directional force without air density, you should use pop force. Pop wind won't necessarily accelerate your particles, it will match their velocity to the wind' s velocity over time, at a rate that is decided by the air density, so it can definitely slow them down.

Tanto
If you want a directional force without air density, you should use pop force. Pop wind won't necessarily accelerate your particles, it will match their velocity to the wind' s velocity over time, at a rate that is decided by the air density, so it can definitely slow them down.

I'm using pop velocity for a directional force and only using pop wind to add noise, I assumed that setting the wind directional velocity to 0,0,0 would make it have no effect, but you're suggesting it's going to try to slow the particles to 0. That would make sense for what I'm seeing.

I see that pop force has a noise section so that looks like the approach I'm after. thanks.

Right, a wind at 0,0,0 is basically a drag force.