User:Tohline/vtk/SimpleCubeTutorial/CubeDetails

Cube Definition Details

A model of virtually any three-dimensional structure can be fed into VisTrails — and understood by the accompanying visualization toolkit (vtk) library of routines — using VTK's Simple Legacy Format. Here we explain how the set of vertices (POINTS) and POLYGONS of a simple cube can be defined using this Simple Legacy Format; this explanation is primarily intended to provide supplemental details for our accompanying Simple Cube Tutorial.

Defining the POINTS (vertices) & POLYGONS of a cube in Simple Legacy Format
# vtk DataFile Version 2.0 Cube example ASCII DATASET POLYDATA POINTS 8 float 0.0 0.0 0.0 <== (x,y,z) coordinates of POINT "0" 1.0 0.0 0.0 <== ... of POINT "1" 1.0 1.0 0.0 <== ... of POINT "2" 0.0 1.0 0.0 <== ... of POINT "3" 0.0 0.0 1.0 <== ... of POINT "4" 1.0 0.0 1.0 <== ... of POINT "5" 1.0 1.0 1.0 <== ... of POINT "6" 0.0 1.0 1.0 <== ... of POINT "7" POLYGONS 6 30 <== (see explanation in the accompanying text) 4 0 1 2 3 <== POLYGON "0": A four-sided polygon formed by connecting POINTS 0, 1, 2, & 3, in that order. 4 4 5 6 7 <== POLYGON "1": A four-sided polygon formed by connecting POINTS 4, 5, 6, & 7, in that order. 4 0 1 5 4 <== POLYGON "2": A four-sided polygon ... POINTS 0, 1, 5, & 4, in that order. 4 2 3 7 6 <== POLYGON "3": A four-sided polygon ... POINTS 2, 3, 7, & 6, in that order. 4 0 4 7 3 <== POLYGON "4": A four-sided polygon ... POINTS 0, 4, 7, & 3, in that order. 4 1 2 6 5 <== POLYGON "5": A four-sided polygon ... POINTS 1, 2, 6, & 5, in that order.

The following 30 (= 6 x 5) integers will define 6 polygons; 5 integers are needed for each polygon.