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The Softbody POP performs soft body deformations similar to the Spring SOP. The edges of the geometry act as "springs", which pull the points back toward their original shape.
When this operator is first activated, the geometry at that time is used. If the SOP changes thereafter, those changes will not be reflected in the geometry produced by the POP network.
The POP creates a new particle system that will move the points of the geometry. To make this particle system invisible to the scene, enable the Hide Particle System parameter. In the info pop-up, the particle system will be denoted as "virtual".
For more stable behavior, see the Squishy Object in DOPs.
Turns the POP on and off.
Specifies the SOP to use.
Use Parameter Values
Use the SOP specified in the SOP parameter below.
Use First Context Geometry
Use the SOP connected to the POP network’s first input.
Use Second Context Geometry
Use the SOP connected to the POP network’s second input.
Use Third Context Geometry
Use the SOP connected to the POP network’s third input.
Use Fourth Context Geometry
Use the SOP connected to the POP network’s fourth input.
Path to the SOP (when Geometry source is set to Use Parameter Values).
Ignore Transform Object
Particles normally use the object space of the SOP being cooked. Turn this parameter on to not transform into the space of the cooking SOP.
Points to be considered stationary.
Fixed Points go to Source Positions
Fixed Points are put to their positions in the Source.
Copy Groups from Source
All Source groups are copied at each frame. Useful if the Fixed Points group contents are animated.
Hide particle system
Make the particle system that controls the softbody deformation hidden (i.e. does not show in scene).
How the springs will behave.
Use Hooke’s law. Force = displacement x spring constant.
Like Hooke’s law except displacement is normalized to the original length of the spring. (Behavior used in Houdini 2.5).
No springs will be used.
Stiffness of the spring.
Initial spring tension before deformations.
Create Local Variables
Create local variables corresponding to inherited attributes.
Add ID Attributes
Add ID and parent attributes.
Add Generation Attribute
Add generation attribute.
Add Origin Attribute
Add origin attribute.
Use as Origin
How to set the origin.
Index as used in origin.
Add Speed Attribute
Add speed attribute (length of velocity vector).
Standard POP local variables
The seconds a particle in the template has been alive.
AX AY AZ
Acceleration of the particle.
BBX BBY BBZ
The point’s relative position in the bounding box.
Point is dead.
Processing iteration number.
A collision for this particle was detected (for example, by the Collision POP) during the processing of this timestep (that is, this iteration of the particle simulation). This variable is cleared at the beginning of each timestep. Note that the collision POP actually detects any collisions which would have occurred the during the previous frame.
Percent of total life used (from 0 to 1).
Expected lifetime of particle.
MAPU MAPV MAPW
Point or vertex texture coordinates.
Total number of points.
Total number of points in source group.
NX NY NZ
The point number of the currently processed point. The
PT is not constant like
ID; it changes based on the number of points.
RESTX RESTY RESTZ
The rest position.
The sliding state of the particle.
Elasticity of a point.
Point is stopped.
1 if particle is stuck to a collision object.
TX TY TZ
Surface UV values.
VX VY VZ
Point spline weight.
Distance from particle to last collision.
HCR HCG HCB
Diffuse color at the collision point on the surface the particle collided with.
ID for last collision. You can control how this attribute is set in the Collision or Limit POP to help distinguish types of collisions.
The time at which the last collision occurred.
The texture map UV coordinates for the surface location where the last collision occurred.
HNX HNY HNZ
The normal at the surface location where the last collision occurred.
HTX HTY HTZ
World space position of the last collision.
The UV coordinates for the surface location where the last collision occurred.
Number of times the particle has collided.
Added by Color POP
Point or vertex alpha value.
CR CG CB
Diffuse point or vertex color.
Added by Property POP
Charge of the particle.
Point is clinging to geometry.
Leader to follow.
SCALEX SCALEY SCALEZ
Added by Proximity POP
Either the point number or id of the particle nearest to this one.
The distance to the nearest particle.
The number of particles within a specified proximity to this particle.
Added by Rotation POP
ROTX ROTY ROTZ
Added by Source POP
ID number, which always remains constant.
Original Source point was birthed from.
Parent’s ID Number.
Added by Speed Limit POP
Added by Sprite POP
Sprite rotation around view axis (in degrees).
Texture coordinate of sprite’s lower-left corner.
Size of sprite in texture space.
Controlled by Suppress Rule POP
Suppress default position rule.
Suppress default velocity rule.
Suppress default up-vector rule.
Suppress default aging rule.
1 if particle is suppressing its default rotation rule.
1 if particle is suppressing its default angular velocity rule.
Added by Up Vector POP
PVX PVY PVZ
UPX UPY UPZ
Absolute speed of particle.