1. A method comprising: determining one or more two-dimensional (2D) images of a plurality of physical objects in a physical environment of a robotic manipulator; determining one or more portions of the one or more 2D images corresponding to a given one or more physical objects of the plurality, wherein the one or more portions virtually distinguish a boundary of at least one distinct object of the given one or more physical objects from boundaries of other physical objects of the given one or more physical objects; determining 3D models corresponding to respective determined portions of the one or more 2D images, each 3D model comprising predicted dimensions of a respective physical object of the given one or more physical objects, the predicted dimensions being based on the respective determined portion of the one or more 2D images that corresponds to the respective physical object and further based on dimensions of one or more other physical objects of the plurality; based on the determined 3D models, selecting a particular physical object from the given one or more physical objects; and providing an instruction to the robotic manipulator to move the particular physical object.