QML Surface3D windowColor and transparency

[Steve3D]

Hi,
I started working with Surface3D in QML and I need to custom it a little. More precisely, I want to make the background transparent to display the Surface3D above other items. The property is "windowColor" of the Surface3D's theme property but no way to make it transparent. I tried the following :

Surface3D {
            id: surfacePlot
            ...

            theme: Theme3D {
                ...
                windowColor: "#00000000" // "transparent" not working, still opaque
                }
          }

QML color : http://doc.qt.io/qt-5/qml-color.html

Surface3D color : it's black in this one https://doc.qt.io/qt-5/qtdatavisualization-qmlsurfacelayers-example.html, white here https://doc.qt.io/qt-5/qtdatavisualization-texturesurface-example.html and grey there http://doc.qt.io/qt-5/qtdatavisualization-qmlsurface-example.html.

So, how to do that? Maybe it is not supported yet, but it's awkward as we can change the color. Why did they skip the transparency?

Re: Qt data visualization background image and transparency support