Data Exchange - STEP Model is imported with no colours

Imported model contains colors as could be seen on attached screenshot from Draw Harness.
Could you please clarify which exactly colors are lost / attach screenshot with expected different colors?

Thanks for the attention.

Maybe I'm doing something wrong (but this is what I use to import all files and all but this work as expected).

Please see the attached source:
_ it first shows top level shapes: we have a compound with no colours, then three solids (with colours);
_ then it shows a tree-like structure of shapes: the compound is still there, but the solids are not, since they are "used" (by the compound I guess). When accessing shapes in this latter way, there's no colour at all.

Your code looks very low-level as it doesn't rely on tools like XCAFDoc_ShapeTool::GetFreeShapes(), XCAFDoc_ShapeTool::IsAssembly(), XCAFDoc_ShapeTool::GetReferredShape(), XCAFDoc_ShapeTool::GetSubShapes() - so that I can't foresee what kind of a tree structure it might display.

This particular STEP file consists of a single Compound having 9 children.
Children are represented by 3 unique Solids instanced 9 times - with different Locations.
Each Solid defines a basic surface color, and this color is overridden by some Faces inside Solid.
Using XCAFDoc_ShapeTool::GetShape() taking TopoDS_Shape on input might be quite tricky, as shapes should be specified with correct Locations, and color might be specified at every shape level.
Tools like XCAFPrs::CollectStyleSettings() might help to create a lookup map of styles.
Displaying a Tree in a usual way prints all shape colors in this document.

#include <Message.hxx>
#include <STEPCAFControl_Reader.hxx>
#include <TDataStd_Name.hxx>
#include <TopExp_Explorer.hxx>
#include <XCAFApp_Application.hxx>
#include <XCAFDoc_ColorTool.hxx>
#include <XCAFPrs_DocumentExplorer.hxx>
#include <XCAFDoc_VisMaterial.hxx>
#include <XCAFDoc_ShapeTool.hxx>

static TCollection_AsciiString getLabelName (const TDF_Label& theLabel)
{
  Handle(TDataStd_Name) aNodeName;
  return theLabel.FindAttribute (TDataStd_Name::GetID(), aNodeName)
       ? TCollection_AsciiString (aNodeName->Get())
       : TCollection_AsciiString();
}

static const int THE_NB_COLOR_CAT = 3;
static const XCAFDoc_ColorType THE_COLOR_CATS     [THE_NB_COLOR_CAT] = { XCAFDoc_ColorGen, XCAFDoc_ColorSurf, XCAFDoc_ColorCurv };
static const char*             THE_COLOR_CAT_NAMES[THE_NB_COLOR_CAT] = { "Generic color: ", "Surface color: ", "Curves color: " };

int main (int theNbArgs, char** theArgVec)
{
  Handle(XCAFApp_Application) anApp = XCAFApp_Application::GetApplication();
  Handle(TDocStd_Document) aDoc;
  anApp->NewDocument ("BinXCAF", aDoc);
  STEPCAFControl_Reader aReader;
  if (!aReader.Perform (theArgVec[1], aDoc))
  //if (!aReader.Perform ("c:/11PI0391_F001-Dima_x_B006_B007.stp", aDoc))
  {
    Message::SendFail() << "STEP file '" << theArgVec[1] << "' reading failed";
    return 1;
  }

  for (XCAFPrs_DocumentExplorer aDocExp (aDoc, XCAFPrs_DocumentExplorerFlags_None); aDocExp.More(); aDocExp.Next())
  {
    const XCAFPrs_DocumentNode& aNode = aDocExp.Current();
    TCollection_AsciiString anIndent (aDocExp.CurrentDepth() * 2, ' ');
    TopoDS_Shape aShape;
    XCAFDoc_ShapeTool::GetShape (aNode.RefLabel, aShape);
    std::cout << anIndent << aNode.Id << " " << (!aShape.IsNull() ? TopAbs::ShapeTypeToString (aShape.ShapeType()) : "") << "\n";

    std::cout << anIndent << "Reference name: '" << getLabelName (aNode.RefLabel) << "'\n";
    if (aNode.RefLabel != aNode.Label)
    {
      std::cout << anIndent << "Instance name:  '" << getLabelName (aNode.Label) << "'\n";
    }

    const XCAFPrs_Style& aStyle = aNode.Style;
    if (aStyle.IsSetColorSurf())
    {
      std::cout << anIndent << "Surface color:  "
                << Quantity_ColorRGBA::ColorToHex (aStyle.GetColorSurfRGBA())
                << " [" << Quantity_Color::StringName (aStyle.GetColorSurf().Name()) << "]"
                << "\n";
    }
    if (aStyle.IsSetColorCurv())
    {
      std::cout << anIndent << "Curves color:   "
                << Quantity_Color::ColorToHex (aStyle.GetColorCurv())
                << " [" << Quantity_Color::StringName (aStyle.GetColorCurv().Name()) << "]"
                << "\n";
    }
    if (!aStyle.Material().IsNull())
    {
      std::cout << anIndent << "Material:       "
                << Quantity_ColorRGBA::ColorToHex (aStyle.Material()->BaseColor())
                << " [" << Quantity_Color::StringName (aStyle.Material()->BaseColor().GetRGB().Name()) << "]"
                << "\n";
    }

    if (!aNode.IsAssembly)
    {
      TDF_LabelSequence aLabSeq;
      XCAFDoc_ShapeTool::GetSubShapes (aNode.RefLabel, aLabSeq);
      Quantity_ColorRGBA aColor;
      anIndent = TCollection_AsciiString ((aDocExp.CurrentDepth() + 1) * 2, ' ');
      int aSubShapeIndex = 0;
      for (TDF_LabelSequence::Iterator aShapeIter (aLabSeq); aShapeIter.More(); aShapeIter.Next())
      {
        const TDF_Label& aSubShapeLab = aShapeIter.Value();
        TopoDS_Shape aSubShape;
        if (!XCAFDoc_ShapeTool::GetShape (aSubShapeLab, aSubShape)) { continue; }
        std::cout << anIndent << "Subshape " << TopAbs::ShapeTypeToString (aSubShape.ShapeType()) << " " << ++aSubShapeIndex << "\n";
        for (int aCatIter = 0; aCatIter < THE_NB_COLOR_CAT; ++aCatIter)
        {
          if (aDocExp.ColorTool()->GetColor (aSubShapeLab, THE_COLOR_CATS[aCatIter], aColor))
          {
            std::cout << anIndent << THE_COLOR_CAT_NAMES[aCatIter]
                      << Quantity_ColorRGBA::ColorToHex (aColor)
                      << " [" << Quantity_Color::StringName (aColor.GetRGB().Name()) << "]"
                      << "\n";
          }
        }
      }

      /*for (TopExp_Explorer aFaceExp (aShape, TopAbs_FACE); aFaceExp.More(); aFaceExp.Next())
      {
        TopoDS_Shape aSubShape = aFaceExp.Current();
        std::cout << anIndent << "Subshape " << TopAbs::ShapeTypeToString (aSubShape.ShapeType()) << " " << ++aSubShapeIndex << "\n";
        for (int aCatIter = 0; aCatIter < THE_NB_COLOR_CAT; ++aCatIter)
        {
          if (aDocExp.ColorTool()->GetColor (aSubShape, THE_COLOR_CATS[aCatIter], aColor))
          {
            std::cout << anIndent << THE_COLOR_CAT_NAMES[aCatIter]
                      << Quantity_ColorRGBA::ColorToHex (aColor)
                      << " [" << Quantity_Color::StringName (aColor.GetRGB().Name()) << "]"
                      << "\n";
          }
        }
      }*/
    }

    std::cout << "\n";
  }

  return 0;
}

0:1:1:1. COMPOUND
Reference name: '11PI0391 F001-Dima x B006 B007'

  0:1:1:1./0:1:1:1:1. SOLID
  Reference name: '11PI0391 B006-Stecca 1'
  Instance name:  '11PI0391 B006-Stecca 1.1'
  Surface color:  #FFFF00FF [YELLOW]
    Subshape FACE 1
    Surface color: #008000FF [GREEN4]
    Subshape FACE 2
    Surface color: #008000FF [GREEN4]
    Subshape FACE 3
    Surface color: #FFFFFFFF [WHITE]
    Subshape FACE 4
    Surface color: #FFFFFFFF [WHITE]
    Subshape FACE 5
    Surface color: #FFFFFFFF [WHITE]
    Subshape FACE 6
    Surface color: #FFFFFFFF [WHITE]
...

> Your code looks very low-level as it doesn't rely on tools like XCAFDoc_ShapeTool::GetFreeShapes(),> XCAFDoc_ShapeTool::IsAssembly(), XCAFDoc_ShapeTool::GetReferredShape(), XCAFDoc_ShapeTool::GetSubShapes()> - so that I can't foresee what kind of a tree structure it might display.

We are actually able to build all the structure we need; it seems only colors (and possibly also layers) are missing sometimes.

I've based my code on:
https://dev.opencascade.org/doc/overview/html/occt_user_guides__xde.html

I see no mention there of, e.g, XCAFPrs_DocumentExplorer.
Where can I find such info?




> Using XCAFDoc_ShapeTool::GetShape() taking TopoDS_Shape on input might be quite tricky, as shapes should be specified with correct Locations, and color might be specified at every shape level.

Since we already have a complex working system and I'd like to change it as little as possible, does "quite tricky" mean impossible?
We can have shape+location: is it possible to get colours from this couple?




> Tools like XCAFPrs::CollectStyleSettings() might help to create a lookup map of styles.

Again, I see it's reference page, but descriptions are very short.
Is there an overview document on all this?



Thanks.


P.S. I realize this is not a bug, then... so perhaps we should move somewhere else?

> P.S. I realize this is not a bug, then... so perhaps we should move somewhere else?

Sure, usually such topics are discussed on the Forum.
https://dev.opencascade.org/forums/data-exchange-and-application-framework

Dear Commenter 1,

please close the issue as not a bug.

Closed.