An exemplary method includes a scene annotation system accessing image scan information of a scene captured by an imaging device of a computing device, generating, based on the image scan information, depth data associated with one or more objects in the scene, providing a two-dimensional (2D) annotation grid for concurrent display together with an image of the scene, at least part of the 2D annotation grid mapped to the depth data, receiving a user input (e.g., via hand gesture, touch screen, mouse, and/or keyboard) that selects a portion of the 2D annotation grid and a corresponding position within the scene where a digital object will be anchored based on the depth data, and instructing the computing device to display, by way of a display device of the computing device and based on the user input, the digital object anchored at the corresponding position within the scene.