# Node count, 3 dim, no attribute, no boundary marker 8 3 0 0 # Node index, node coordinates 1 0.0 0.0 0.0 2 1.0 0.0 0.0 3 1.0 1.0 0.0 4 0.0 1.0 0.0 5 0.0 0.0 1.0 6 1.0 0.0 1.0 7 1.0 1.0 1.0 8 0.0 1.0 1.0
The attributes, which are typically floating-point values of physical quantities (such as mass or conductivity) associated with the points, are copied unchanged to the output mesh. If -p switch is used, each new Steiner point inserted on segments of the mesh has attributes assigned to it by linear interpolation. Furthermore, if -q, -a, or -i is selected, each new point added to the mesh to improve mesh quality has attributes zero.
If the fourth entry of the first line is '1', the last column of the remainder of the file is assumed to contain boundary markers. Boundary markers are used to identify boundary points (points resting on PLC facets). The .node file produced by TetGen contains boundary markers in the last column unless they are suppressed by the -B switch. The boundary marker associated with each point in an output .node file is chosen as follows:
TetGen can determine which points are on the boundary, input with the boundary marker zero (or use no markers at all) will result in output with boundary marker (1) for all points on the boundary.