Generate Force Fields with nParticles

You can generate a force field from your nParticle object that either pushes or pulls nCloth objects or other nParticle objects away from or toward your nParticles. Positive Point Field Magnitude values produce a force that pushes Nucleus objects away, while negative Point Field Magnitude values generate a force that pulls objects towards the nParticles. The active area or region of the force field is defined by a Point Field Distance attribute. You can use the Point Field Scale ramp to control how Point Field Magnitude is distributed along the area defined by Point Field Distance.

nParticle objects can also generate a Self Attract force. By adjusting Self Attract, an nParticle object’s individual particles can be made to attract or repel each other.

To generate a force field for an nParticle object

Select the nParticle object that you want to generate force fields.
In the Attribute Editor, select the nParticle object’s nParticleShape tab.
In the Point Field Generation section, turn on force fields by selecting one of the following from the Point Force Field list:
- ThicknessRelative: Generates a Point Force Field that is relative to the radius of the nParticle object. See Radius.
- World Space: Generates a Point Force Field that is relative to world space.
Adjust Point Field Magnitude to increase or decrease the Point Force Field strength.
Adjust Point Field Distance to specify how far from the nParticles’ center the force field will be active.
Nucleus objects located in the area specified by the Point Field Distance are affected by the nParticle’s Point Force Field.

Controlling a Point Force Field using the Point Field Scale ramp

You can use the Point Field Scale ramp to provide additional control of your nParticle object’s Point Force Field. For example, you can define a Point Field Scale curve that varies Point Field Magnitude along the area defined by Point Field Distance.

For information about nParticle attribute ramps, see nParticle internal ramps and per-particle attributes.

To control a Point Force Field using the Point Field Scale ramp

Select the nParticle object that you want to generate point force fields, and in the Attribute Editor, adjust the object’s Point Force Field attributes.
In the Point Field Scale section of the Attribute Editor, set the ramp options by doing the following:
- Create the Point Field Scale curve by setting values for Selected Position and Selected Value. For more information, see Set nParticle internal ramps.
- Set an Interpolation method to determine how Point Field Magnitude blends between each position on the ramp. See Interpolation.
- Set Point Field Scale Input to determine which attribute is used as the input attribute for the Point Field Scale ramp.
- Set Input Max to define the range of the Point Field Scale ramp. See Input Max.

Setting Point Field Dropoff

You can use the Point Field Dropoff ramp to specify how much the Point Field Magnitude drops off nParticle’s center and the edge of the area defined by Point Field Distance.

For information about nParticle attribute ramps, see Set nParticle attribute ramps.

To set the Point Field Dropoff

Select the nParticle object that you want to generate point force fields, and in the Attribute Editor, adjust the object’s Point Force Field and Point Field Scale attributes.
In the Point Field Dropoff section of the Attribute Editor, set the ramp options by doing the following:
- Create the Point Field Curve curve by setting values for Selected Position and Selected Value. See Set nParticle internal ramps.
- Set an Interpolation method to determine how Point Field Dropoff blends between each position on the ramp. See Interpolation.