pFriction Node

pFriction applies progressive damping to the particles crossing its area. Without friction, particles emitted with an initial speed keep that speed forever - which is unrealistic in most cases (real life has air that slows things down).

Two separate frictions: Velocity Friction for translation speed, Spin Friction for rotation speed. They can be controlled independently.

• Effects Library: Tools > Particles > pFriction
• Quick add: right-click in the Node Editor → Add Tool > Particles > pFriction

• Particle Input (orange) - output of a particle node.
• Region Input (green/magenta) - optional. A 2D bitmap or 3D mesh that defines where the friction applies. Without a Region, friction applies everywhere in the field.

Explosion that dies down:
pEmitter (high radial Velocity) → pFriction (moderate Velocity Friction)
                                  → pRender
(the debris gradually slows down)

Particles settling on the ground:
pEmitter → pDirectionalForce (gravity) → pBounce (Elasticity 0.3)
        → pFriction (high Velocity Friction) → pRender
(the particles bounce, then stop)

Localized friction zone (region):
pEmitter → pFriction ← Shape 3D (friction sphere)
        → pRender
(the particles only slow down inside the sphere)

Velocity Friction

Strength of the resistance to movement. 0 = no effect. 0.01-0.05 = light friction (standard air). 0.1+ = strong friction (particles that stop quickly).

Spin Friction

Strength of the resistance to rotation. Independent of Velocity. Useful to stop sprites spinning on themselves without stopping their translation.

Random Seed

Randomizer seed (for subtle per-particle friction variations).

Conditions (Sets)

Friction only on certain sets.

• An explosion that runs out of steam - debris emitted violently + moderate Velocity Friction = debris that slows down naturally (as if the air were braking it).
• Confetti / leaves settling - gravity + high friction = a slow, swaying fall rather than an abrupt free fall.
• Particles on the ground coming to rest - after pBounce, a high pFriction = particles on the ground decelerate and eventually stop (instead of bouncing forever).
• Sparks dying out - high Velocity Friction = sparks that slow down just before disappearing (end of lifespan), a more realistic effect than a simple fade.
• Localized resistance zone - Region Mesh = a water sphere: particles entering the sphere slow down drastically (simulates entering a fluid).
• Rotation that settles - Spin Friction to gradually stop sprites from spinning (e.g. a coin that falls and lands flat).
• Dissipating smoke - moderate Velocity Friction on smoke = a gradual loss of momentum, a more natural look.

• 0.01-0.05 = standard air, 0.1+ = a thick medium (water, foam), 0 = a vacuum with no resistance.
• Independent Spin Friction - it can differ from Velocity Friction. E.g. particles that slow down in translation but keep their spin (paper flying and spinning in place).
• Combine with pBounce - a classic: pBounce stops the fall through collision, pFriction damps the successive bounces until the particles come to rest.
• Regions for different zones - friction in water (sphere Region = water volume) vs friction in air (Region all) = realistic physics depending on the environment.
• Velocity Friction is constant over time - for friction that increases over time (e.g. a particle that slows down more and more), use pCustomForce with an expression.
• Avoid friction too early - if pFriction is too strong right after pEmitter, particles stop before they move. Let the initial momentum play out before damping.
• For a realistic fluid (liquid, gel), combine a very high pFriction + subtle pTurbulence = particles drifting slowly as in a viscous fluid.