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Setup attributes
Type 
Name 
Description 



(Point) Set by the Planar Patch or Planar Patch from Curve SOPs. Used to determine warp/woof directions for anistropy. 


Scale by Attribute in Vellum Constraints defaults to these sorts to adjust the scale. Should be 
Sim attributes: geometry
Note
Geometry is also considered particles, so all of POP Attributes apply.
Dynamics: parameters
Type 
Name 
Description 



(Point) How much to scale wind effects when the face of the cloth is heading straight into the wind versus sliding parallel to it. For hair, Note This controls the innate behavior of the cloth property, the strength of the wind is controlled with 


(Point) The resistance of a particle to rotational hair constraints. If this is zero, the particle will not rotate. 


(Point) Default 1. A value of 1 or a reference to itself means not welded, but something might be welded to this point.
The value is a point number, unless there is an



(Point, Detail) How much to scale the static friction ( Note These are combined by multiplication. So if two objects have a 


(Point) How much to scale the effect of a Pressure constraint on a perpoint basis, from Note This attribute can be used for interesting inflation effects, but should be used with care as it can also lead to unbalanced forces if the 
Dynamics: state
Type 
Name 
Description 



(Point) For 2nd order we need the previous frames position and velocity ( 


(Point) Hair requires point orientations and the corresponding angular velocity (w). Same previous/last. 


(Point) This is a standard POP attribute, but it is used and respected by Vellum. Autosleep and awaken will manipulate the stopped attribute. Pins that are to be released can be controlled using stopped rather than setting the mass to zero. Stopped controls both orientation and position updates via bits 0 and 1.

Collision
Type 
Name 
Description 



(Point) Radius at each point. Triangles are fattened at their corners by spheres of the corner 


(Point) Controls soft priority of collisions. Only greater/less matters, not magnitude of difference. 


(Point) A value of 0 means this point will use self collisions or external collisions.
This point will use self collisions or external collisions. (Note the double negative: setting
Collisions are disabled for this point. If any points in an edge or triangle are disabled (not Autoenable/disable does bitwise tricks with this value:
This trick means that to disable a point independent of autodetection, you should set the value to 


(Point) The default value is 10000. Stores how much of the original 


(Point) The default value is "". Stores a pattern for the objects and collision groups to not collide with. This means the default empty string will enable all collisions. To disable all collisions, use the string The currently solving Vellum object always uses the object name Note that this will match against both the object name and the collision group. The latter is specified with the string 


(Point) The default value is "". Gives the collision group that this point belongs to. If this matches a collision ignore label, it will not engage in collision detection. The default empty string will only match against the 
Targeting
Type 
Name 
Description 



(Point) The target path and point number for any pins when the Target parameter is set in Vellum Source. If 


(Point) Affect the strength of the pinned points using a 0..1 weighting value. 
Breaking
Type 
Name 
Description 



(Point) The threshold for breaking welds and branch welds, measured against the breaktype, which can be one of the following: 
Pressure
Type 
Name 
Description 



(Point) When a point is part of a Pressure constraint, these attributes hold values computed during constraint evaluation. The 
Internal worker variables
Removing/adding attributes every frame is expensive, so we have a few internal things that leak out.
Type 
Name 
Description 



(Point) Constraint displacements/weights. Likely of last iteration, so out of date. 


(Point) Identifies each generated patch in a simulation so it can be updated/replaced. 
Sim attributes: constraints
There are many types of constraints, so the meaning of these variables is often dependent on the constraint type. They usually live on the primitive.
Dynamics: parameters
Type 
Name 
Description 



(Prim) Note Higher than 


(Prim) The initial "distance" of the constraint. The units are variable. Distance constraints use distance, bend constraints use angle in degrees, volume and pressure constraints use volume. The actual dynamics use only 


(Prim) Orientation constraints need a rest orientation, so store a quaternion here. This vector is also used to store target positions for pin constraints. 


(Point) The original point position in rest space, used by 


(Prim) 


(Prim) 


(Prim) The distance from the rest state at which the stiffness of the constraint drops off to zero, or increases from zero to full stiffness, depending on the direction of the dropoff. A negative values indicates a decreasing dropoff, where the stiffness starts at full strength and decreases to zero at the Dropoff distance from the rest state. A positive value indicates an increasing dropoff, where the stiffness starts at zero and increases to full stiffness at the specified distance from rest. For stretch constraints this value is in length units; for bend constraints it is stored in degrees. The effective stiffness value used in constraint solving will be stored in 


(Prim) Type of the constraint.
Constraints the points to be
Constraint between a point and a location on a primitive, usually created with the _Use Closest Location on Primitive option on the Vellum Constraints SOP. In that case
A fourpoint constraint. The points represent the 4 points of two triangles that share an edge. The constraint is applied to maintain an angle along the shared edge.
A threepoint constraint. The constraint maintains the distance between the middle point and the centroid of the triangle. This maintains the bend of lines.
A threepoint constraint. Maintains the dihedral angle measured at the middle points. This is used by the String constraint types.
A fourpoint constraint. Maintains the volume of the tetrahedron described by the four points.
A manypoint constraint. All the points represent a surface of a mesh. Volume is computed on the mesh and stored on the points, and then all the points are inflated or deflated to maintain that volume.
Pins a point to a certain world space location.
An additional constraint created for Attach to Geometry constraints when __Tangent Stiffness_ is enabled. This constraint keeps the constrained point aligned with
the target object normal, as specified in the
Pins the orientation of the point to match the rest orientation.
Two point constraint. Constrains the orientation of points on an edge to be consistent, thereby creating torsion effects along hairs.
Two point constraint. Combination of both a distance constraint and a bend constraint for edges. This is used by hair.
A tetrahedral constraint that allows compressing the tetrahedron along the local space direction specified in its points'
An AsRigidAsPossible stretch constraint on triangles that minimizes deviation from the triangle’s rest shape, stored in
An AsRigidAsPossible stretch constraint on tetrahedra that minimizes deviation from the tetrahedron’s rest shape, stored in
A constraint that attempts to keep the original shape of the constrained points, as stored in the constraint geometry’s 
Dynamics: state


The amount of stress applied by the constraint. 
Sliding


(Prim) The rate at which the target location should slide along the primitives specified by 
Breaking


(Prim) The threshold for breaking the constraint, measured against the 
Plasticity


The threshold for applying plasticity to the constraint, which modifies the constraint’s 
Targeting


(Prim) If set to 1 for pin constraints, the solver will lookup the constrained point’s 
Internal worker variables


(Prim) The amount of work done by a constraint, possibly along different stiffness or compression stiffness axes. Generally you should use the stress attribute instead to determine how much work a constraint is doing. 


(Prim) Array of points affected by this constraint. 