Vector normal to the surface

[jdopazo]

I would to get a vector perpendicular to the surface in a node. Can anybody help me?

Thanks,

Javi

[escolano]

Nowadays a node doesn't store any pointer to its 'source geometrical entity' (point, line, surface, or volume), if any.
if the node belong to some triangle/quadrilateral you can calculate its normal as an approximation to the geometry surface normal at this node.

From Tcl scripting you can also get the normal of a parametric surface at a u,v coordinates

Code: Select all

GiD_Info parametric surface $id normal $u $v

e.g. to get the normal (unitary) of the surface 2 at paremeters (0.5,0.5)
set normal [GiD_Info parametric surface 2 normal 0.5 0.5]

you can also calculate the u,v parametric coordinates that better approximate a 3D coordinate (x,y,z), in this case the location of the node, with

Code: Select all

GiD_Info parametric surface $id uv_fromcoord $x $y $z