Deselect item in 3D context

We developped a 3D web-app for computers and touch devices in which you can decorate your interior with wallpaper, furnitures and so on. You can select an object or a wall (click or touch) inside the 3D scene and have a menu with some contextual actions (move, replace, delete...).

But, as everything is interactive, wherever you click you select something. Therefore, you can never have nothing selected. So, I'm looking for a way to deselect the selected item.

I've got some leads, but I would like to know what is, in your opinion, the most intuitive way to deselect an object ?