How to read STEP layer description - Forum Open Cascade Technology

jeanmarc.leroux...
Mon, 11/04/2019 - 12:55

Forums:

Hi,

I have the following content in my STEP file:

#14=PRESENTATION_LAYER_ASSIGNMENT('1',
'{052BF154-476B-4C88-8FBB-936FDCD2AF3D}',(#62568,#37507,#62569,#393,#37508,
#37509,#37510,#37511,#37512,#37513,#62570,#62571,#62572,#37514));

I'm using the XCAFDoc_DocumentTool::LayerTool to read the layers:

        Handle(XCAFDoc_LayerTool) myLayers = XCAFDoc_DocumentTool::LayerTool(hDoc->Main());

        myLayers->GetLayerLabels(layers);
        for (int i = 1; i < layers.Length(); ++i)
        {
            // const Standard_GUID nameGuid("TDataStd_Name");
            Handle(TDataStd_Name) nameAttr = new TDataStd_Name();
            Handle(XCAFDoc_GraphNode) graphNodeAttr = new XCAFDoc_GraphNode();

            graphNodeAttr->SetGraphID("efd212e8-6dfd-11d4-b9c8-0060b0ee281b");

            auto l = layers.Value(i);

            l.FindAttribute(nameAttr->ID(), nameAttr);
            bool found = l.FindAttribute(graphNodeAttr->ID(), graphNodeAttr);

            LOG_INFO("nb label children: " << l.NbChildren());
            LOG_INFO("nb label attributes: " << l.NbAttributes());
            LOG_INFO("name: " << nameAttr->Get());
            LOG_INFO("nb graph node children: " << graphNodeAttr->NbChildren());
        }

I can read the layer name and "content" just fine. But the PRESENTATION_LAYER_ASSIGNMENT entity also includes a description field.

I need to read that description field. How can I do that?

Thank you for your help,

jeanmarc.leroux...
Tue, 11/05/2019 - 09:46

Answering my own question after a few hours poking around in the OpenCascade code:

    Handle(XSControl_WorkSession) session = aReader.Reader().WS();
    Handle(Standard_Type) tSVPLA = STANDARD_TYPE(StepVisual_PresentationLayerAssignment);
    Handle(Interface_InterfaceModel) Model = session->Model();
    Standard_Integer nb = Model->NbEntities();

    for (Standard_Integer i = 1; i <= nb; i ++)
    {
        Handle(Standard_Transient) enti = Model->Value(i);
        
        if (!enti->IsKind(tSVPLA))
            continue;
        
        Handle(StepVisual_PresentationLayerAssignment) SVPLA = Handle(StepVisual_PresentationLayerAssignment)::DownCast(enti);
        
        Handle(TCollection_HAsciiString) descr = SVPLA->Description();
        Handle(TCollection_HAsciiString) hName = SVPLA->Name();

        layerNameToDescription[hName->ToCString()] = descr->ToCString();
    }