TYPE: POP
TITLE: Limit POP

The Limit POP determines when the particles have reached some
sort of boundary limit. The Attributes tab is used to add attributes that 
store information about the particle's last collision. With the exception of 
the distance attribute, these attributes are not set unless a collision 
occurred. Local variables are usable in parameters denoted with a *.

This POP modifies the following attributes: accel, dist, hitCd, hitN, hitid,
hitpos, hitposuv, hittime, hituv, numhit.

Parameters:
    Activation              - Turns the POP on and off	/activate
    Source Group            - Subset of points to act on
Limits
    Type                    - type of boundary limit
    +Limit                  - positive plane value	/limitposx /limitposy /limitposz
    -Limit                  - negative plane value	/limitnegx /limitnegy /limitnegz
Behavior
    Behavior                - How particle behaves after collision 
    Collision Event         - Generate event when any point collides
    Collision Group         - Group to contain collided points
    Preserve Group          - Add particles to group instead of clearing group first
    *Hit Index              - Index to use as Hit ID		/hitindex
    Bounce Accuracy         - Max # of inter-frame bounces to perform	/bounce
    *Gain Tangent           - Energy loss tangent to collision 	/gaintan
    *Gain Normal            - Energy loss normal to collision	/gainnml
Attributes 
    Add Num Hit Attr           - Number of times collided 
    Add Hit ID Attr            - Hit ID
    Add Hit Time Attr          - Time of collision
    Add Hit Position Attr      - Where collision occurred
    Add Hit Normal Attr        - Normal where collision occurred 
    Add Distance Attr          - Distance from current position to collision

Local Variables
    Overview - The standard local variables are usable in this POP.  Please
               refer to the Houdini manual for more details.

See Also: Collision, SoftLimit
