Procedural drawing

It is also possible to draw 3D symbols using OpenGL commands to draw triangles, lines, etc.

A simple way is to have the shape stored in a file with GiD mesh ASCII format

These symbols can be drawn oriented by a vector (e.g. typical case of a force), or by a 3x3 rotation matrix (for a more special case), with a scale factor depending on some field, related to global XYZ axis or local axis of curves or surfaces (using its tangent and normal vectors)

We provide a gid_draw_opengl Tcl package with some interesting procs to facilitate common tasks and usual shapes like an arrow to represent a force, a double T section of a beam, etc.

The code is at <gid>\scripts\gid_draw_opengl

(the subfolder symbols has some .msh files)