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Meshed surface files format

The file format used to describe the geometry of surfaces is illustrated below. The surface is simply meshed as an assembly of triangle elements.

  1. The first word in the file must be *NODES, followed by an arbitrary number of lines with four numbers each : node identification number, X-coordinate, Y-coordinate and Z-coordinate.

  2. The second keyword *TRIANGLE must be placed right below the preceding line, and no blank line is allowed. This keyword must be followed by an arbitrary number of lines, with four numbers each : triangle identification number, first, second and third node identification number.

A brief example is presented below. The right handed frame convention is used to determine the normal direction. This point is of prime importance when contact elements are used. You can easily check that the orientation of your surface is correct within the 3D view window : the light rays are always reflected in the direction normal to the surface.

*NODES I XI YI ZI J XJ YJ ZJ K XK YK ZK *TRIANGLE I I J K

Tip

No matter which node identification numbers are used, the surface will always display correctly provided that the mesh remains consistent. You can skip as many node numbers as you wish between two consecutive lines, which improves readability.