Exporting GLTF with material labels

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Description

Hey i wrote this example code to export a gltf file, but my material labels are lost after the export.

Expected Behavior

GLTF-File with material "name":"Testmaterial_blue"

Actual Behavior

GLTF-File with material "name":"mat_0"

Sample Code or DRAW Tcl Script

`#include <BRepPrimAPI_MakeBox.hxx>
#include <gp_Pnt.hxx>
#include <XCAFDoc_ShapeTool.hxx>
#include <XCAFDoc_ColorTool.hxx>
#include <TDF_Label.hxx>
#include <TDF_LabelSequence.hxx>
#include <Quantity_Color.hxx>
#include <TopoDS_Shape.hxx>
#include <TDocStd_Application.hxx>
#include <TDocStd_Document.hxx>
#include <TDataStd_Name.hxx>
#include <TCollection_ExtendedString.hxx>
#include <XCAFDoc_DocumentTool.hxx>
#include <XCAFDoc_MaterialTool.hxx>
#include <RWGltf_CafWriter.hxx>
#include <Message_ProgressScope.hxx>
#include <Message_ProgressRange.hxx>
#include <BRepMesh_IncrementalMesh.hxx>

int main() {

gp_Pnt corner(0, 0, 0); 
Standard_Real dx = 1000.0, dy = 5000.0, dz = 3000.0; 
TopoDS_Shape boxShape = BRepPrimAPI_MakeBox(corner, dx, dy, dz).Shape();



const Standard_Real linearDeflection = 0.5;
BRepMesh_IncrementalMesh mesher(boxShape, linearDeflection);

Handle(TDocStd_Document) doc = new TDocStd_Document("ShapeDoc");


Handle(XCAFDoc_ShapeTool) shapeTool = XCAFDoc_DocumentTool::ShapeTool(doc->Main());
Handle(XCAFDoc_ColorTool) colorTool = XCAFDoc_DocumentTool::ColorTool(doc->Main());
Handle(XCAFDoc_MaterialTool) matTool = XCAFDoc_DocumentTool::MaterialTool(doc->Main());


TDF_Label shapeLabel = shapeTool->AddShape(boxShape);


Quantity_Color blueColor(Quantity_NOC_BLUE1); // Blau
colorTool->SetColor(shapeLabel, blueColor, XCAFDoc_ColorGen);


Handle(TCollection_HAsciiString) asciiName = new TCollection_HAsciiString("Testmaterial_blue");
Handle(TCollection_HAsciiString) asciiDes = new TCollection_HAsciiString("Testmaterial_blue");
Standard_Real density = 1.0;
Handle(TCollection_HAsciiString) asciidenstype = new TCollection_HAsciiString("Testmaterial_blue");
Handle(TCollection_HAsciiString) asciidensname = new TCollection_HAsciiString("Testmaterial_bllue");



TDF_Label materialLabel = matTool->AddMaterial(asciiName, asciiDes, density, asciidensname, asciidenstype);
matTool->SetMaterial(shapeLabel, materialLabel);



Message_ProgressScope progressScope;
Message_ProgressRange progress = progressScope.Next();
TColStd_IndexedDataMapOfStringString fileInfo;
fileInfo.Add("Author", "Your Name");
fileInfo.Add("Description", "");


const char* outputFileName = "output.gltf";
RWGltf_CafWriter gltfWriter(outputFileName ,Standard_False);






return 0;

}
`

Operating System

Windows

Compiler

GCC

Bitness

64-bit

OCCT Version

latest

Additional Files

No response

[gkv311]

You need to use XCAFDoc_VisMaterialTool to export visual materials into glTF. XCAFDoc_MaterialTool is for physical materials (e.g. density), which are not exported to glTF.

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Ok thank you. Do you have an example how to use it?

[dpasukhi]

XCAFDoc_VisMaterialTool is a main tool to work with material and textures for XCAF.
To work with that tool you need to have similar sample:

// Creates tool itself
Handle(XCAFDoc_VisMaterialTool) aVMTool = XCAFDoc_DocumentTool::VisMaterialTool(myXdeDoc->Main());
// Creates material, see XCAFDoc_VisMaterial
Handle(XCAFDoc_VisMaterial) aMat = new XCAFDoc_VisMaterial();
// Sample for common type
XCAFDoc_VisMaterialCommon aMatXde;
aMatXde.IsDefined     = true;
aMatXde.AmbientColor  = theMaterial->AmbientColor;
aMatXde.DiffuseColor  = theMaterial->DiffuseColor;
aMatXde.SpecularColor = theMaterial->SpecularColor;
aMatXde.Shininess     = theMaterial->Shininess;
aMatXde.Transparency  = theMaterial->Transparency;
if (!theMaterial->DiffuseTexture.IsEmpty())
{
  aMatXde.DiffuseTexture = new Image_Texture(theMaterial->DiffuseTexture);
}
aMat->SetCommonMaterial(aMatXde);
aMat->SetRawName(new TCollection_HAsciiString(theMaterial->Name));

// Sets the material into material label
const TDF_Label aMatL = aVMTool->AddMaterial(aMat, "MaterialName");

// Sets connection to some ShapeLabel
const TDF_Label aShapeL = ...;
aVMTool->SetShapeMaterial(aShapeL, aMatL )

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ok and theMaterial is defined by Graphic3d_MaterialAspect ? or how do i define it?

[dpasukhi]

theMaterial is just a some container which store information.
Please check headers to know used types of data

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is there any example for this? Or can you help me with my code?

`#include <BRepPrimAPI_MakeBox.hxx>
#include <gp_Pnt.hxx>
#include <TopoDS_Shape.hxx>

#include <BRepMesh_IncrementalMesh.hxx>

#include <TDocStd_Document.hxx>
#include <TDataStd_Name.hxx>
#include <TCollection_ExtendedString.hxx>
#include <TDF_Label.hxx>

#include <XCAFDoc_DocumentTool.hxx>
#include <XCAFDoc_ShapeTool.hxx>
#include <XCAFDoc_VisMaterialTool.hxx>
#include <XCAFDoc_VisMaterial.hxx>
#include <Graphic3d_MaterialAspect.hxx>
#include <Quantity_Color.hxx>
#include <TCollection_HAsciiString.hxx>

#include <RWGltf_CafWriter.hxx>
#include <Message_ProgressScope.hxx>

#include

int main() {
// === 1. Geometrie erstellen ===
// Erstellt eine einfache Box als TopoDS_Shape.
gp_Pnt corner(0, 0, 0);
Standard_Real dx = 1000.0, dy = 5000.0, dz = 3000.0;
TopoDS_Shape boxShape = BRepPrimAPI_MakeBox(corner, dx, dy, dz).Shape();

// Die Form muss vernetzt (meshed) werden, damit sie in Formaten wie glTF sichtbar ist.
const Standard_Real linearDeflection = 0.5;
BRepMesh_IncrementalMesh mesher(boxShape, linearDeflection);

// === 2. XCAF-Dokument und Werkzeuge einrichten ===
// Ein Dokument dient als Container für Shapes, Materialien, Farben etc.
Handle(TDocStd_Document) doc = new TDocStd_Document("ShapeDoc");

// Holen der spezialisierten Werkzeuge, um mit dem Dokument zu arbeiten.
Handle(XCAFDoc_ShapeTool) shapeTool = XCAFDoc_DocumentTool::ShapeTool(doc->Main());
Handle(XCAFDoc_VisMaterialTool) visMatTool = XCAFDoc_DocumentTool::VisMaterialTool(doc->Main());

// Fügt die Box-Geometrie zum Dokument hinzu und erhält ein "Label" dafür.
// Ein Label ist eine Referenz auf ein Objekt im Dokument.
TDF_Label shapeLabel = shapeTool->AddShape(boxShape);

// === 3. Visuelles Material erstellen und zuweisen ===

// 3.1. Materialeigenschaften mit Graphic3d_MaterialAspect definieren

// Graphic3d_MaterialAspect ist eine Klasse, die alle gängigen
// visuellen Eigenschaften eines Materials (Farbe, Glanz etc.) zusammenfasst.
struct MyMaterialData
{
TCollection_AsciiString Name;
Quantity_Color AmbientColor;
Quantity_Color DiffuseColor;
Quantity_Color SpecularColor;
Standard_Real Shininess;
Standard_Real Transparency;
TCollection_AsciiString DiffuseTexture;
};

Handle(MyMaterialData) theMaterial = new MyMaterialData();
theMaterial->Name = "Holz Eiche";
theMaterial->DiffuseColor = Quantity_Color(0.54, 0.27, 0.07, Quantity_TOC_RGB); // Braun
theMaterial->Shininess = 0.2;
theMaterial->Transparency = 0.0;
theMaterial->DiffuseTexture = "";
theMaterial->AmbientColor = theMaterial->DiffuseColor; // 20% der Grundfarbe
theMaterial->SpecularColor = Quantity_Color(Quantity_NOC_WHITE);

// 3.1. Einen allgemeinen "Container" für das visuelle Material erstellen.
Handle(XCAFDoc_VisMaterial) visMaterial = new XCAFDoc_VisMaterial();

// Sample for common type
XCAFDoc_VisMaterialCommon aMatXde;
aMatXde.IsDefined = true;
aMatXde.AmbientColor = theMaterial->AmbientColor;
aMatXde.DiffuseColor = theMaterial->DiffuseColor;
aMatXde.SpecularColor = theMaterial->SpecularColor;
aMatXde.Shininess = theMaterial->Shininess;
aMatXde.Transparency = theMaterial->Transparency;



if (!theMaterial->DiffuseTexture.IsEmpty())
{
    aMatXde.DiffuseTexture = new Image_Texture(theMaterial->DiffuseTexture);
}
visMaterial->SetCommonMaterial(aMatXde);
visMaterial->SetRawName(new TCollection_HAsciiString(theMaterial->Name));

// Sets the material into material label
const TDF_Label aMatL = visMatTool->AddMaterial(visMaterial, "MaterialName");


// Sets connection to some ShapeLabel

visMatTool->SetShapeMaterial(shapeLabel, aMatL);


// === 4. Dokument als glTF-Datei exportieren ===
Message_ProgressScope progressScope;
Message_ProgressRange progress = progressScope.Next();
TColStd_IndexedDataMapOfStringString fileInfo;
fileInfo.Add("Author", "Your Name");
fileInfo.Add("Description", "");
const char* outputFileName = "output.gltf";
RWGltf_CafWriter gltfWriter(outputFileName, Standard_False);

if (!gltfWriter.Perform(doc, fileInfo, progress)) {
    std::cerr << "Fehler: Der Export in die glTF-Datei ist fehlgeschlagen." << std::endl;
    return 1;
}

std::cout << "Erfolgreich! Datei wurde erstellt." << std::endl;
return 0;



return 0;

}`

[dpasukhi]

I shared a sample of code already. Your code looks valid and you apply material on top label.
If something is not working, you can debug you code and check where is the issue.
You also can save XCAF as xbf and check it using Inspector to analyze tree structure. Inspector can be downloaded together with release package of OCCT (see releases)

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Thank you the code is working now, but the material in the gltf file is still called mat_0 and not the given name. Did i miss something ?