See the problemtype <gid>\problemtypes\Examples\customlib\condition_symbols.gid
there is a condition
<condition n="self_weight_3d" pn="Self weight" ov="volume" ovm="" icon="select" help="Set gravity value giving a Modulus and a Direction" groups_icon="groupCreated">
<symbol proc="ConditionSymbols::draw_selfweight" orientation="global"/>
<value n="modulus" pn="Gravity" v="9.81" units="m/s^2" unit_magnitude="Acceleration" help="Gravity acceleration value" string_is="double" icon="data"/>
<value n="direction" pn="Direction" v="0.0,0.0,-1.0" fieldtype="vector" dimensions="3" help="The resultant unit vector is considered" icon="data"/>
</condition>
its <symbol> node has attributes
proc="ConditionSymbols::draw_selfweight"
orientation="global"
and the proc is defined as
proc ConditionSymbols::draw_selfweight { values_list } {
foreach item $values_list {
lassign $item key value unit
set data($key) $value
#set unit($key) $unit
}
set modulus $data(modulus)
set direction [split $data(direction) ,]
set opposite_direction [math::linearalgebra::scale_vect -1.0 $direction]
set full_filename [file join [gid_filesystem::get_folder_standard scripts] gid_draw_opengl symbols selfweight.msh]
set color_lines black
set color_surfaces blue
set list_id [gid_draw_opengl::create_opengl_list_from_file_mesh_oriented_z_direction $full_filename $color_lines $color_surfaces $opposite_direction]
return $list_id
}
the values_list provide the values of each specific condition instance, first are extracted the ones named ‘modulus’ and ‘direction’ and then is called the predefined proc
gid_draw_opengl::create_opengl_list_from_file_mesh_oriented_z_direction
that read the mesh from the path the a mesh file selfweight.msh and draw it with OpenGL commands, creating an drawing list for better performance and return its id
Then creating a model, loading this problemtype, and assigning this condition to a volume, can be drawn for example with the contextual menu: Draw symbols
and the shape is drawn oriented with the direction 0,0,-1 (global direction -Z)
