AVS Modules							ucd to prim
US EPA Visualization Center					May 5, 1992

NAME
	ucdtoprim - Generate geometric primitives from ucd data

SUMMARY
	Name	ucdtoprim
	Type	Mapper
	Inputs	Data  		ucd 		REQUIRED
		Colors		colormap	OPTIONAL

	Outputs	output_geom  	geom

	Parameters
	Name		Type	Default	Choices
	Species		integer	0	0 -- 8
	Scale		real	1.0	-10.0 -- 10.0
	Primitive	radio	Prism	Prism,Spere

DESCRIPTION
	This module takes an input ucd structure and generates
	a geometric primitive (sphere or prism) for each node of 
	the structure. Primitives are colored according to a
	selected value at the node and an optional input colormap. 
	If no colormap is provided, primitives will be mapped with 
	a grey scale.

INPUTS
	Data - ucd (required)
	This input is the ucd structure to be mapped to geometric
	primitives. Only node data will be considered and connectivity
	information is virtually ignored. The structure may have
	multiple values at the nodes, but only one will be represented
	at a time.

	Colors - colormap (optional)
	Colormap to map the node data values to primitive colors. 
	If no colormap is provided, primitives will be colored 
	according to a grey scale.

PARAMETERS
	Species
	This value specifies which of the data values at the node 
	(which often correspond to different species) will be used 
	to color and size the primitive. Species numbers start at 0.

	Primitive
	Select between sphere and prism primitives. The sphere 
	primitive will be centered at the node coordinates and 
	colored according to the selected value (species). The
	prism primitive will originate at the node coordinates
	and extend in the z direction a distance determined by
	the selected value and the Scale paramter. Prisms will
	be colored according to selected value.

	Scale
	This value specifies the scale of the geometric primitive.
	For spheres, the scale will be used as the sphere radius.
	For prisms, the scale will be multiplied with the node 
	value to produce the prism length along the z axis. Negative
	scales can be used to change between right- and left-hand
	coordinate systems.

OUTPUTS
	output_geom - geom

EXAMPLE NETWORKS

		read ucd 	generate colormap
		   |			|
		   |			|
		   |    -----------------
		   |    |
	         ucd to prim
		      |
		      |
		 geometry viewer

LIMITATIONS
	The prism primitive really works best when data lies in a
	plane orthogonal to the z axis. If data is 3D, or 2D but
	does not lie in an XY plane, prisms may overlap and obscure
	one another.

	A maximum of 16,000 nodes are allowed.

RELATED MODULES
	Modules which can produce the ucd input:
		read ucd
		field to ucd
		any other module which outputs a ucd structure
	Modules which can produce the colormap input:
		generate colormap
		color range
	Modules which can process the geometry output:
		geometry viewer
		render geometry

SEE ALSO

AUTHOR
	Penny Rheingans, US EPA Visualization Center