# Create and triangulate a Plane

Hi everyone,

I am new with opencascade. I would like to create a geometric entity (plane/cylinder/circle/sphere...) and triangulate this entity in order to draw it in my own viewer (not in the opencascade one).

// This is how i create my plane :

gp_Pnt p(i_p->getCenter().x(), i_p->getCenter().y(), i_p->getCenter().z());

gp_Dir dir(i_p->getNormal().x(), i_p->getNormal().y(), i_p->getNormal().z());

gp_Pln plane(p, dir);

// Then a create the shape of the face :

const Standard_Real aRadius = 10.0;

const Standard_Real aHeight = 25.0;

BRepBuilderAPI_MakeFace aPlane(plane);

TopoDS_Shape aShape = aPlane.Shape();

// Now I triangulate the shape :

const Standard_Real aLinearDeflection = 0.01;

const Standard_Real anAngularDeflection = 0.5;

BRepMesh_IncrementalMesh aMesh(aShape, aLinearDeflection, Standard_False, anAngularDeflection);

aMesh.Perform();

if (aMesh.IsDone() == false) return;

TopExp_Explorer exFace;

// for each Face (object)

for (exFace.Init(aShape, TopAbs_FACE); exFace.More(); exFace.Next()) {

// get the face

TopoDS_Face face = TopoDS::Face(exFace.Current());

TopLoc_Location loc;

// get the triangulation

Handle(Poly_Triangulation) tri = BRep_Tool::Triangulation(face, loc);

if (tri.IsNull()) continue;

}

My problem is : tri.IsNull() is always equal to true... I don't understand where is my mistake because the value of aMesh.isDone() is equal to "true" and in the documentation that mean "the triangulation was performed and has success". I use the same method to read and triangulate a step file and it's work.

I am very grateful if someone knows the correct solution to do that.

Thk,

Manon Hi Manon,

do you really need a infinite plane? I'm not sure if OCC bounds such a plane inside BRepBuilderAPI_MakeFace.

What happens if you try something like this

BRepBuilderAPI_MakeFace aPlane(plane, 0.0, 1.0, 0.0, 1.0);

?

Greets,

Patrik Hello Patrick,

It works ! Thanks you very much, I totally forgot to restrict the plane...

Manon