Particle Size attributes

The Particle Size attributes set particle radius. You can use the Radius Scale ramp to map radius on a per-particle basis using nParticle attributes, such as Lifespan, Color, and Mass, as the ramp's input values.

Radius

Radius of individual particles belonging to the nParticle object. The Radius setting provides the input value for the Radius Scale ramp.

Radius Scale

Lets you set per-particle radius based on the Radius attribute value. On the ramp, the vertical component represents values from 0 (no radius) to 1 (equal to the Radius attribute value). See Set attributes using ramps.

If the Radius Scale Input is set to Off, the per-particle attributes are deleted. If it is set to any other value, the radius per-particle attributes are created if they don’t already exist.

Radius Scale Input

Specifies which attribute is used to map the Radius Scale ramp values.

Off

When off, the per-particle attributes are deleted. If you want to use an expression with the per-particle attribute, you need to manually add them again. See About nParticle internal ramps and per-particle attributes.

Age

The per-particle attribute values are determined by the nParticle’s age, which is based on the particle Lifespan mode. See nParticle Lifespan attributes.

Normalized Age

The per-particle attribute values are determined by the normalized age of the nParticle. To use Normalized Age, the nParticle object must have a defined lifespan. For example, the nParticle object’s Lifespan Mode attribute must be set to Constant or Random range.

When Normalized Age is used, The per-particle attribute values are mapped within the range of the nParticle object’s lifespan.

Speed

The per-particle attribute values are determined by nParticle speed.

Acceleration

The per-particle attribute values are determined by nParticle acceleration.

Particle ID

The per-particle attribute values are determined by the nParticle’s ID. Particle IDs are unique and generated at the beginning of the particle’s lifespan.

Randomizing ID

The per-particle attribute values are determined by a randomized nParticle ID.

Input Max

Sets the maximum value for the range used by the ramp.

Radius Scale Randomize

Sets a random multiplier for the per-particle attribute values.