AVS Modules						            surface mesh
NOAA/ERL/Forecast Systems Laboratory


NAME

	surface mesh - create a 3D wire mesh object from a polytriangle object

SUMMARY

	Name		surface mesh

	Type		mapper

	Inputs		geometry

	Outputs		geometry

	Parameters

	    Name		Type		Default		Min Max Choices

	    mesh x res		integer		0		0, unbounded
	    mesh y res		integer		0		0, unbounded
	    mesh z res		integer		0		0, unbounded
	    show polygons	toggle		on

DESCRIPTION

	The surface mesh module creates a 3D wire mesh from a polytriangle
	object of a 3D field.  Typically, polytriangle objects are used to
	represent surfaces such as those created by the isosurface and field to
	mesh modules.  The surface mesh module creates a wire mesh of such a
	surface by passing planes that are perpendicular to the coordinate
	axes and finding the line segments that are the intersections between
	the surface and these planes.  The mesh resolution (or distance between
	the planes) along each axis is independent from that along the other
	axes.  The edges of the polygons defined by the polytriangles may also
	be shown.

INPUTS

	Input Geometry

	    The input for surface mesh must be a geometry object defined by
	    polytriangle strips.  Any other type of object is ignored.

PARAMETERS

	mesh x res
	mesh y res
	mesh z res

	    The mesh res parameter control the spacing between the slicing 
	    planes for each axis.  A mesh res value of zero disables slicing
	    along that axis.  The actual spacing between the slicing planes for
	    a particular axis is
	   
			(extent max - extent min) / (mesh res - 1)

	    where the extent max and extent min are the maximum and minimum
	    extent of the object in the axis direction.

	show polygons

	    To show the edges of the polygons defined by the polytriangles, the
	    show polygons parameter should be set to on.  Presentation of the
	    polygons is independent from that of the mesh.

OUTPUTS

	Output Geometry

	    All of the lines created by surface mesh are placed in an object
	    named "surface mesh".  This includes not only any mesh lines, but
	    the polygon edges as well.

EXAMPLES

	This example creates a wire mesh from an isosurface of a field.

		           READ FIELD
		                |
		           ISOSURFACE
		                |
		          SURFACE MESH
		                |
                         RENDER GEOMETRY
                                |
                          DISPLAY PIXMAP

LIMITATIONS

	This module is not terribly efficient since it uses disjoint line
	segments rather than polylines.  Perhaps a more efficient version will
	be available in the future.

AUTHOR

	Phil McDonald, NOAA/ERL/Forecast Systems Laboratory


NOAA/ERL/Forecast Systems Laboratory
AVS Modules						            surface mesh