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Overview
While the Source POP emits particles from existing geometry, the Location POP simply emits particles from a 3D coordinate.
If you're looking for a way to explicitly set the coordinates of existing particles, use the Position POP.
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).
Const. 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.
Const. 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.
Locals
TX, TY, TZ
Particle position
Examples
The following examples include this node.
AverageSpeed Example for Vector channel node
fieldforce Example for Field Force dynamics node
ParticleClusters Example for Cluster geometry node
ConvertMetaballs Example for Convert Meta geometry node
CopyCubes Example for Copy Stamp geometry node
pscaleVOPSOP Example for Add Attribute VOP node
parameterVOP Example for Parameter VOP node
ParticleVolumeCollision Example for Volume Sample VOP node
See also 