1. A method comprising: identifying, by a computing device, an object in an environment of a vehicle, wherein the computing device is configured to have access to one or more motion characteristics of the vehicle; receiving a first three-dimensional (3D) point cloud depicting a first view of the object; determining a reference point on the object in the first 3D point cloud; receiving a second 3D point cloud depicting a second view of the object, wherein the second view includes at least a portion of the first view, and wherein the second 3D point cloud is captured a given period of time after the first 3D point cloud is captured; determining a transformation between the first view and the second view based on matching the portion of the object depicted in the first view to a corresponding portion depicted in the second view; estimating a projection of the reference point from the first view relative to the second view based on the transformation so as to trace the reference point from the first view to the second view; and determining one or more motion characteristics of the object based on the projection of the reference point, the given time period, and the one or more motion characteristics of the vehicle.