Putting objects within rootNode over guiNode

Is it possible?
For example, I already put a 2d background image on guiNode,then I want to put a 3d object over the background.
any idea? thanks so much.

Yes. It will be projected as an orthographic image instead of perspective.

The Gui node is just like any other node except it is orthographic.

If I understood the question right the answer is no.

Objects on the GUI node are always drawn in front of objects in the root node.

However… you can put 3d objects in the GUI node - just be aware that it’s not got perspective projection.

You can also create a perspective viewport on top of the gui viewport, etc… it gets trickier the deeper down the rabbit hole you choose to go.

You might have an easier time putting your 2D gui (with billboard) in the 3D window if what we said above is confusing.

many thanks