Name:     ucd_plumb
          "Plumb Line UCD sampler"

Author:   Ian Curington, Advanced Visual Systems, Inc.

Type:     Mapper

Language: C

Source:   ucd_plumb.c

Input:    UCD
          struct upstream geom

Outputs:
          Geometry of cross-hairs
          int    picked node number
          float  x-coord
          float  y-coord

Parameters:
           Node_Num   integer,  selection for hi-lighted node
           Size       float     size of marker
           Offset     float     Z dist away from object
           Downsize   int       subsample of markers v.s. nodes
           Flat       int       flat plane of markers, or follow Z in data

Description:
   The plumb_line module annotates the top surface of a UCD structure
   with red cross hairs over each node.  The cross hairs are pickable,
   and change colour. The node number and x-y coordinate value of the picked node
   is shown and can be controlled with the an integer typein,
   and are output on one integer and two float output ports.
   This can be used to control modules that use position dials, perhaps
   to create a cutting sheet or a graph plot of the selected
   data section. Downsize control allows a subset of node positions to
   be visible, while size and offset controls specify the marker shape
   and position.