Use the sampled attributes

These are Niagara particle attributes. The sampler writes them before later modules run.

Attribute	Use
Particles.Position	Position already set by the sampler, including NormalOffset.
Particles.TUNS.Position	Stored sampled position, including the offset. Useful as an effect origin.
Particles.TUNS.Normal	Surface normal; use for outward motion or orientation.
Particles.TUNS.UV	UV at the sample; use for color or reveal textures.
Particles.TUNS.MaskWeight	Baked density weight; use for brightness or size.
Particles.TUNS.TriCoord	Triangle and barycentric coordinate for this sample.
Particles.TUNS.Triangle	Triangle index.
Particles.TUNS.Velocity	Skeletal velocity; zero for the static module.
Particles.TUNS.Valid	Whether the sample is usable. Invalid samples are also marked not alive.

Example: inherit the mesh’s motion

1. Use the skeletal sampler in Particle Spawn. Add Set Variables immediately after it.
2. Add Particles.Velocity to Set Variables. Open its value menu and bind Particles.TUNS.Velocity.
3. Keep Solve Forces and Velocity in Particle Update. It integrates that velocity as the particle moves.
4. Play the skeletal animation. Each new particle receives the surface velocity at its birth; it can then move independently.

123

1. 1
   Set Variables

   Place after TUNS so the sampled attributes exist.

2. 2
   TUNS.Velocity

   Bind this as the value of Particles.Velocity.

3. 3
   Solve Forces and Velocity

   Integrates the particle’s movement in Update.

For outward motion, use Particles.TUNS.Normal × Speed instead. For texture color or reveal effects, use Particles.TUNS.UV as the texture coordinates.