A system and method are provided for determining a size of a virtual object in a virtual environment. The virtual object may represent an object in physical space. The system and method may obtain image data of the object from a camera, obtain camera metadata indicative of an angle of view of the camera, estimate an object distance between the object and the camera, and estimate a physical size of the object in physical space by determining an image size of the object in the image data, and determining a relation between the image size and the physical size of the object on the basis of the camera metadata and the object distance. Accordingly, the size of the virtual object in the virtual environment may be determined in accordance with the physical size of the object. Virtual objects may thus be given realistic relative sizes in the virtual environment. A further advantage may be that there is no need for a calibrated system of multiple cameras and a calibrated rendering environment.