Stl Import

The poly_triangulation stores 2 informations: the vertexs of the triangles (Nodes array) and the triangles. Each triangle contains three indexs, one per vertex, that refer to the vertexs array.
You need to create a [Handle]Poly_Triangulation passing the number of the triangles and vertexs (triangles *3). Then you just load the vertexs and then the triangles with the right values.
A simple-unoptimized way if you don't need poly_connect:
Handle(Poly_Triangulation) T = new Poly_Triangulation(Tri_Num, TriNum*3); (or inverted)
for (i = 1; i < ... ){ // Remember 1-Based
T->Nodes(i*3)->SetValue(STLTriangle[i]) [i-1 if it is 0 based]
T->Nodes(i*3+1)->SetValue(STLTriangle[i])
T->Nodes(i*3+2)->SetValue(STLTriangle[i])
T->Triangles(i)->Set(i*3,i*3+1,i*3+2)
}

It's the same old Vertexs-Indexs structure :O)
If you have time, do it in the right way : instead of adding each vertex, try to avoid to insert it if it is duplicate.Doing so allow you to use Poly_Connect that gives some usefoul informations (like the triangles belonging to a vertex).

Creating a TOPODS_Shell or Compound using the facets it's possible (and easier to display), but ... why ? :)

Sorry for my english, I hope you understand this !