Correct location of parts after a STEP import

Dear Patrik,

thank you very much. I have tried this already before asking and, unfortunately, it had not really worked out.
Updated code:

Handle(TDocStd_Document) doc;
Handle(XCAFApp_Application) anApp = XCAFApp_Application::GetApplication();
anApp->NewDocument(filename,doc);

STEPCAFControl_Reader reader;
reader.ReadFile(filename);
reader.Transfer(doc);

Handle(XCAFDoc_ShapeTool) myAssembly = XCAFDoc_DocumentTool::ShapeTool(doc->Main());

TDF_LabelSequence FreeShapes;
myAssembly->GetFreeShapes(FreeShapes);
TDF_LabelSequence shapes;
myAssembly->GetComponents(FreeShapes.Value(1),shapes,true);

for(Standard_Integer i=1; i<=shapes.Length(); ++i)
{
	TDF_Label label = shapes.Value(i);
	TopLoc_Location location = myAssembly->GetLocation(label);
	gp_Trsf transformation = location.Transformation();

	TopoDS_Shape shape;
	myAssembly->GetShape(label,shape);

	TopAbs_ShapeEnum type = shape.ShapeType();
	if(type!=0)
	{
		BRepBuilderAPI_Transform xform(shape, transformation);
		shape = xform.Shape();

		BRepMesh_IncrementalMesh BMesh(shape,0.1,Standard_True);
		StlAPI_Writer STLwriter;
		std::stringstream stream;
		stream << i;
		std::string filename;
		stream >> filename;
		filename += ".stl";
		STLwriter.Write(shape,filename.c_str());
	}
}

The positions change, but not really the way I would like them to, see the new printscreen.
I have even tried inverting the transformation with transformation.Invert(), without success.

Thanks for hints!

Hi Peter,
thanks, I did not think of this! Do I just multiply the transformations then or is there something more elaborate to do?
When I multiply them like this:

Handle(TDocStd_Document) doc;
Handle(XCAFApp_Application) anApp = XCAFApp_Application::GetApplication();
anApp->NewDocument(filename,doc);

STEPCAFControl_Reader reader;
reader.ReadFile(filename);
reader.Transfer(doc);

Handle(XCAFDoc_ShapeTool) myAssembly = XCAFDoc_DocumentTool::ShapeTool(doc->Main());

TDF_LabelSequence FreeShapes;
myAssembly->GetFreeShapes(FreeShapes);
TDF_LabelSequence shapes;
myAssembly->GetComponents(FreeShapes.Value(1),shapes,true);

for(Standard_Integer i=1; i<=shapes.Length(); ++i)
{
	TDF_Label label = shapes.Value(i);
	TopLoc_Location location = myAssembly->GetLocation(label);
	gp_Trsf transformation = location.Transformation();

// The new part:
	TDF_Label refLabel;
	if(myAssembly->GetReferredShape(label, refLabel))
	{
		TopLoc_Location refLocation=myAssembly->GetLocation(refLabel);
		gp_Trsf refTransformation=location.Transformation();
		transformation=refTransformation * transformation;
	}

// The same as before:
	TopoDS_Shape shape;
	myAssembly->GetShape(label,shape);

	TopAbs_ShapeEnum type = shape.ShapeType();
	if(type!=0)
	{
		BRepBuilderAPI_Transform xform(shape, transformation);
		shape = xform.Shape();
		BRepMesh_IncrementalMesh BMesh(shape,0.1,Standard_True);
		StlAPI_Writer STLwriter;
		std::stringstream stream;
		stream << i;
		std::string filename;
		stream >> filename;
		filename += ".stl";
		STLwriter.Write(shape,filename.c_str());
	}
}

they are still not correctly positioned (printscreen attached). I have also tried changing the order of the transformations and --- somewhat surprisingly --- the result looks the same (shouldn't they be non-commutative?).

Thanks for suggestions!

Dear Patrik,
thank you for your hint and sorry for my late reply.

I tried adding the "Standard_True" parameter to BRepBuilderAPI_Transform as you had suggested.
I did so both in my code from 11 July, 2017 19:37 and the code from 12 July, 2017 - 10:38.
Unfortunately, it does not change anything in either of the situations.

I've had a closer look at the transformations and there is a thing I do not understand.
The shapes corresponding to i=6 and i=9 both represent the same geometrical shape and they both have the same transformation, represented by the matrix
-1 0  0  2.5
0  1  0  -17.5
0  0 -1  -20
0  0  0  1
Consequently, they both end up in the same location, which is not what I want.
Multiplication by the transformation of the referred shape does not change anything about it.
I feel I am missing something rather basic ...
 

Thanks for further suggestions.