## Mass operator

The Mass operator allows you to control the mass of particles. The mass value of a particle will affect the way it behaves within the bind solver, as well as the PhysX solver.

#### Mass

• Value: the initial absolute mass value assigned to particles.

• Variation %: the per-particle percentage of variation to apply.
• Clamp min: the minimum allowable mass value.

• Clamp max: the maximum allowable mass value.

• Relative to property: controls whether assigned mass values will be relative to a particle property.

• Property: the property type which the mass value will be relative to.

• *Threshold: the target threshold that particle property will be compared to, when assigning mass values.

• Exponent: the exponent that particle property ratios will be raised to. Larger exponent values will increase the mass disparity between large and small property values.

• Invert: controls whether the resulting property ratio will be inverted.

• Relative to bindings: controls whether masses will be affected by their distance to deactivated/kinematic particles in their binding network.

• Particle bindings: regular particle bindings will be considered in the breadth-first traversal of the binding network.

• PhysX bindings: PhysX bindings will be considered in the breadth-first traversal of the binding network.

• Multiplier: the multiplier applied to masses, relative to their depth in the breadth-first search.

• Exponent: the exponent applied to the depth-relative multiplier. The larger the exponent, the greater affect the multiplier will have on particles relative to their depth in the breadth-first search.

#### Interpolation

• Normal interpolation: linearly interpolates the current value towards the target value.

• Full interpolation on entry: linearly interpolates the particle's current value towards the target value, unless the particle's event age is 0 - then the particle's current value will be set to the target value.

• Full interpolation at time of birth: linearly interpolates the particle's current value towards the target value, unless the particle's age is 0 - then the particle's current value will be set to the target value.

• Curve interpolation (static): uses a curve to interpolate the particle's current value towards the value assigned to the particle when the particle first entered the event.

• Curve interpolation (dynamic): uses a curve to interpolate the particle's current value towards the target value.

• Duration: the number of frames over which the curve interpolation will be performed.

• Value: the amount to linearly interpolate values each frame.

• Variation %: the amount of variation to apply to the interpolation value.

#### PhysX Center of Mass

• Set: controls whether to override the local center of mass offset value on PhysX particles.

• X/Y/Z: the axis values for the center of mass offset, relative to the local particle transform.

#### Uniqueness

• Seed: the seed value for all varied parameters.