Select a vertex, an edge and a face with mouse - Forum Open Cascade Technology

Hakan Kaya
Mon, 02/28/2022 - 10:36

Forums:

Hi everyone,

I want to have vertex, edge, face or full body selection on AIS_Shape according to selection mode. Actually, if the vertex that I want to go from is selected, I need to obtain the coordinates of the vertex. If edge is selected I need to calculate the length. Surface area even if face is selected...

I can highlight with my command.

myViewerWidget->getContext()->Activate(TopAbs_FACE, Standard_True);

But when the shape is clicked it returns me all of its vertices or surfaces.

My code in the mouse click event is as follows;

if (theEvent->button() == Qt::LeftButton) {
    qDebug() << "Left click pressed.";

    if(!myContext->DetectedOwner().IsNull()){
        Handle(AIS_InteractiveObject) picked;
        myContext->InitSelected();
        picked = myContext->DetectedInteractive();
        Handle(AIS_Shape) aShape=Handle(AIS_Shape)::DownCast(picked);

        TopoDS_Shape topShape = aShape->Shape();

        // Vertex
        for(TopExp_Explorer vertEx(topShape, TopAbs_VERTEX); vertEx.More(); vertEx.Next()) {
            TopoDS_Vertex aVertex = TopoDS::Vertex(vertEx.Current());
            gp_Pnt aPnt = BRep_Tool::Pnt(aVertex);
            qDebug() << "Vertex: " << aPnt.X() << " " << aPnt.Y() << " " << aPnt.Z();
        }

        // Face
        for(TopExp_Explorer vertEx(topShape, TopAbs_FACE); vertEx.More(); vertEx.Next()) {
            TopoDS_Face aVertex = TopoDS::Face(vertEx.Current());
            GProp_GProps System;
            BRepGProp::SurfaceProperties(aVertex, System);
            Standard_Real Area = System.Mass();
            qDebug() << "Area: " << Area;
        }
    }

}

How can I have only one corner or edge of any AIS_Shape that I want? What am I missing?

Thanks, Hakan.

Kirill Gavrilov
Mon, 02/28/2022 - 11:26

Your code retrieves the shape from AIS_Shape, which would be entire shape of this presentation. To get picking results you should work with Owner objects instead.

myContext->InitSelected();
Handle(SelectMgr_EntityOwner) aSelOwner  = myContext->SelectedOwner();
Handle(StdSelect_BRepOwner)   aBRepOwner = Handle(StdSelect_BRepOwner)::DownCast (aSelOwner);
if (!aBRepOwner.IsNull())
{
  TopoDS_Shape aSubShape = aBRepOwner->Shape();
}

Hakan Kaya
Mon, 02/28/2022 - 13:16

Thanks for your answer Kirill. I know I'm tiring you but when I do as you say I can't catch any TopoDS_Shape.

My code:

Handle(SelectMgr_EntityOwner) aSelOwner  = myContext->SelectedOwner();
Handle(StdSelect_BRepOwner)   aBRepOwner = Handle(StdSelect_BRepOwner)::DownCast (aSelOwner);
if (!aBRepOwner.IsNull())
{
    qDebug() << "Shape is live.";
    TopoDS_Shape aSubShape = aBRepOwner->Shape();

    for (TopExp_Explorer wExpl(aSubShape, TopAbs_VERTEX); wExpl.More(); wExpl.Next()) {
        const TopoDS_Vertex &curVertex = TopoDS::Vertex(wExpl.Current());
        const gp_Pnt curVertexPos = BRep_Tool::Pnt(curVertex);

        qDebug() << "Vertex: " << curVertexPos.X() << " " << curVertexPos.Y() << " " << curVertexPos.Z();
    }
}

This is how I set the viewer content. Could there be an issue with that?

// Make Box
TopoDS_Shape aTopoBox = BRepPrimAPI_MakeBox(3.0, 4.0, 5.0).Shape();
Handle(AIS_Shape) anAisBox = new AIS_Shape(aTopoBox);

anAisBox->SetColor(Quantity_NOC_AZURE);

myViewerWidget->getContext()->Display(anAisBox, Standard_True);
myViewerWidget->getContext()->Deactivate();

const int mode = AIS_Shape::SelectionMode(TopAbs_VERTEX);
myViewerWidget->getContext()->Activate(anAisBox, mode);

myViewerWidget->fitAll();
// Make Box