With Qt 5, the Qt 3D module was introduced, which streamlined access to the OpenGL rendering API. This new module was used as the foundation for the Qt 3D Designer editor and the accompanying runtime. It can be used to create highly dynamic GUIs, featuring a combination of 2D and 3D elements.
It is quite similar to hand-crafted QML-based GUIs, but provides a more streamlined workflow, ease of adding animations, and previewing the project. It's similar to the Qt Designer Studio, which focuses more on 2D GUIs, but this one is not available for free, instead requiring you to purchase a license.