In one embodiment, example systems and methods relate to a manner of generating 3D representations from monocular 2D images. A monocular 2D image is captured by a camera. The 2D image is processed to create one or more feature maps. The features may include depth features, or object labels, for example. Based on the image and the feature map, regions-of-interest corresponding to vehicles in the image are determined. For each region-of-interest a lifting function is applied to the region-of-interest to determine values such as height and width, camera distance, and rotation. The determined values are used to create an eight-point box that is a 3D representation of the vehicle depicted by the region-of-interest. The 3D representation can be used for a variety of purposes such as route planning, object avoidance, or as training data, for example.