Location particle node

Emits particles at a location in space.

All

Parameters

Local variables

Overview

While the Source POP emits particles from existing geometry, the Location POP simply emits particles from a 3D coordinate.

Synonym alert: if you're looking for a way to explicitly set the coordinates of existing particles, you want the Position POP.

Placing an Emitter in the viewer

To...	Do this
Place Emitter anywhere in the scene	Click the Emitter tool on the Create Particles tab. Move the cursor into the scene view. You can hold Alt to move off the construction plane. Click to place the particle system anywhere in the scene view and press Enter to confirm your selection. If you press Enter without clicking, Houdini places the emitter at the origin. Click play to see the particles.
Place Emitter at the origin	Press Ctrl + on the Emitter tool on the shelf.

Parameters

Location

System

Coordinate system of the Coordinates parameter below.

Cartesian	Specify location as X, Y, and Z coordinates.
Cylindrical	Specify location as radius, theta, and Z coordinates (where theta is the angle between the X and Y axes).
Polar	Specify location as radius, theta and phi coordinates (where phi is the angle between the X and Z axes).

Coordinates

Location in space to emit particles from.

Birth

This operator has two methods for emitting particles. You can use these methods together or separately:

Impulse creates a certain number of particles each time the node cooks.
Constant creates a certain number of particles per second.

Impulse Activation	Turns impulse emission on and off. Impulse emits the number of particles in the Impulse birth rate below each time the operator cooks. A value of 0 means off, any other value means on.
Impulse Birth Rate	Number of particles to emit each time the node cooks (when Impulse activation is on).
Constant Activation	Turns constant emission on and off. Impulse emits the number of particles in the Constant birth rate below each second. A value of 0 means off, any other value means on.
Constant Birth Rate	Number of particles to emit per second (when Constant activation is on).
Birth Group	Name of a group to put the new points into.
Preserve Group	If the Birth group already exists, append the new particles to the group instead of replacing its contents.
Life Expectancy	How long the particle will live (in seconds).
Life Variance	Particles will live the number of seconds in Life expectancy, plus or minus this number of seconds. Use 0 for no variance.

Attributes

The parameters on this tab let you control which and how attributes are initialized on the emitted particles. See the POP locals page for explanations of these variables.

Velocity	Set or add to velocity attribute.
Variance	Variance to velocity set above. The node will add +/- from 0 to this number along each axis to the Velocity parameter.
Ellipsoid Distribution	By default, the variance (if any) is distributed in a box, the size of which is determined by the Variance parameter. When this option is on, the variance is distributed in an ellipsoid instead.
Add ID Attributes	Add ID and parent attributes to the created particles.
Add Generation Attribute	Add the generation attribute to the created particles.
Add Origin Attribute	Add the origin attribute to the created particles. The origin attribute holds an arbitrary number that can help you identify the source of a particle.
Origin Index	Value for the origin attribute (when Add origin attribute is on).
Add Speed Attribute	Add speed attribute. In Houdini, the speed attribute is the length of the velocity vector.

Local variables

TX, TY, TZ

Particle position

Usages in other examples

Example name	Example for
CopyCubes	Copy surface node	Load \| Launch
FieldForceSmoke	Field Force dynamics node	Load \| Launch
DentingWithPops	SOP Solver dynamics node	Load \| Launch
MultiAxisOrbiting	Orbit particle node	Load \| Launch
SimpleCreep	Creep particle node	Load \| Launch
CreepFromCenter	Creep particle node	Load \| Launch
TorqueBox	Torque particle node	Load \| Launch
AttractToGrid	Attractor particle node	Load \| Launch