MultiSlice

DESCRIPTION

This module creates multiple slices of a lattice and outputs them as geometry. The slices are produced from the index space of the lattice, not the coordinate space.

The data of the lattice is used to color the output slices. Scalar data produces greyscale; two values map to red and cyan; three values map to red, green, and blue; four values map to red, green, blue, and alpha. An optional colormap may be used to map the first data component to a color.

If non-unity alphas are used for transparency in Render, the sorted delayed transparency mode should be selected for the best rendering results. Otherwise, the best performance will be obtained with simple blended transparency.

The polygons of the output slices may be computed using two or four triangles per rectangle, depending on whether the cell centers are ignored or used, respectively. Using cell centers gives a closer match to the bilinearly interpolated data of the lattice, at twice the cost in memory and processing speed. Thus using cell centers is appropriate for smaller lattices or where the rendering artifacts of the two-triangle method produce unacceptable images. The color at the cell center is bilinearly interpolated from the colors at the corners, which is the same as data interpolation in the case of true coloring, and does not introduce additional artifacts when a colormap is used.

INPUTS

Port: Input Lattice
Type: Lattice
Constraints: 3-D
This is the 3D input lattice to be sliced.

Port: Colormap
Type: Lattice
Optional: This port is optional.
Constraints: 1-D
Constraints: 4-vector
Constraints: float
This is an optional colormap lattice.

WIDGETS

Port: Number
Type: Slider
This widget determines the number of slice planes. This many planes will be produced when the offset is zero. An offset of more than zero may send some planes beyond the bounds of the lattice.

Port: Spacing
Type: Slider
This widget specifies the spacing between slice planes.

Port: Offset
Type: Slider
This widget specifies the number of samples to offset to the first slice plane.

Port: Axis
Type: Option Menu
Menu Item: XY
Menu Item: YZ
Menu Item: ZX
This widget specifies which indexing axis to slice along. The choices are the first two (XY), the last two (YZ), and the first and last (ZX). Note that the names XY, YZ, and ZX may not correspond to the world coordinates. For example, if the lattice is curvilinear, the indexing axes may not even be straight in coordinate space.

Port: Center Points
Type: Option Menu
Menu Item: Ignore
Menu Item: Use
This widget specifies whether to use the bilinearly interpolated center point of each cell when triangulating the cell. Ignoring the center creates two triangles per cell, but the rendered value at the cell center ignores two vertices of the cell. Using the cell center creates four triangles per cell at additional cost in memory and time.

OUTPUTS

Port: Slice Output
Type: Geometry
This is the output geometry.

KNOWN PROBLEMS

SEE ALSO

LatToGeom, OrthoSlice.
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© The Numerical Algorithms Group Ltd, Oxford UK. 2000

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