TYPE: SOP
TITLE: WireCapture SOP

WireCapture works in conjunction with the WireDeform SOP by assigning wire
capture weights to points that fall within a given radius of the capture
primitives in the second input. The primitives are typically bezier or NURBs
curves although primitives such as NURBs grids can also be used. The closer the
point is to the primitives from the second input, the stronger the point is
attached, ie. higher weight value.

The WireCapture SOP will not visibly change the geometry (except to possibly
add point colors for feedback). To actually change the geometry, append a
WireDeform SOP with the same second input.

Parameters:
    Group                   - Optional point group to assign capture weights.
			      If empty, this implies that all points should
			      be assigned.
 Parameters
    Kernel Function         - Dropoff function used to convert the distance
			      of a point to a capture primitive weight. This
			      function is normalized according to each
			      primitive's capture parameters.
    Treat Polygons As Lines - This specifies the behaviour when the
			      capture primitives from the second input are
			      polygons. If this is turned on (default), then
			      each closed polygon is treated a line primitive
			      starting from its first vertex.  If off, then
			      each closed polygon is used as a face primitive
			      with uv coordinates based off of the first three
			      vertices.
    Destroy Existing Weights	- This specifies whether existing
				  wire capture weight attributes are destroyed.
				  If off, then a Blend Factor can be given to
				  say how the new capture weights are blended
				  with the ones already in the input geometry.
				  Note that since the capturing is based on
				  primitive order, all layered WireCapture SOPs
				  which have this parameter turned off must
				  have the same second input.
    Visualize Weighting	    - If on, this will generate point colour attributes
			      reflecting the wire capture weights.
    Visualize Type	    - This specifies the type of visualization used
			      when Visualize Weighting is turned on.
			      The Single Primitive visualize type shows the
			      weight of each primitive along a colour gradient.
			      For points affected by multiple primitives, it
			      will use the blended deformation weight for
			      colouring.
			      Multiple Primitives uses a blend of primitive
			      colours found in the second input. If they don't
			      exist, then Single Primitive is used.
    Visualize Mode	    - This specifies the gradient used for
			      visualization.
	Infra-red	- Utilizes the entire color spectrum where they range
			  from blue (0) to red (1).
	White to Red	- Provides a gradient which varies from white (0) to
			  red (1).
	Grayscale	- Provides a gradient which ranges from black (0) to
			  white (1).
    Zero Weight Point Color - This specifies the color used for points which
			      are not affected by any capture primitives when
			      using the Multiple Primitive visualize type.
Capture
    Initialize From Primitives	- This will initialize the parameters below
				  using the primitives found in the second
				  input. An entry is created for each primitive
				  using it's primitive number.
    Initialize From Groups  - This will initialize the parameters below using
			      the primitive groups found in the second input.
			      An entry is created for each named primitive
			      group.
    Number of Primitives    - This specifies the number of primitive parameter
			      sets that we wish to capture with. Each set below
			      has a toggle to indicate whether it should be
			      active.
    Primitive		    - This specifies the primitive group for which the
			      Subgroup, Falloff Start, U Radius and Lookup,
			      and U Range parameters apply.
    Subgroup		    - This specifies the subgroup of points (within
			      that listed in the Group parameter) that the
			      parameters below are assigned.
    Min/Max Weight	    - This gives the range to scale weight values into.
    Falloff Start	    - This is a percentage of the current radius from
			      which points within are assigned a weight of 1.
			      The values for this must be between 0 and 1. It
			      may vary along the primitive's parametric u value
			      if a channel exists in the Lookup parameter.
    U Radius and Lookup	    - The two parameter components here are multiplied
			      together to determine the effective capturing
			      radius of the primitives. If the second component
			      (Lookup) contains a channel, then it is evaluated
			      using the current u value of the primitive
			      instead of time. This allows you to specify a
			      varying radius along the u length of the
			      primitive.  The length of the channel (ie. from
			      its first to last key) is scaled to the u length
			      of the primitive. Note that if the lookup curve
			      is a channel reference, then the length of the
			      channel must match that of the referenced one.
    U Range		    - This specifies a u subrange of the primitive to
			      use for capturing. The first component specifies
			      the start u value and the second component gives
			      the ending u value. Both of these must be between
			      0 and 1. Furthermore, the start value must be
			      less than or equal to the end value.

See also: WireDeform 
