1. A non-transitory computer-readable storage medium configured to store instructions for creating a model in a three-dimensional (3D) environment, the model representing a real-world object, the instructions, when loaded and executed by a processor, causes the processor to: given a two-dimensional (2D) sketch comprised of a plurality of sketch entities, automatically create one or more 3D parts in the 3D environment corresponding to respective groupings of the sketch entities in the 2D sketch; create a derived layout sketch in the 3D environment associated with a first 3D part, wherein the derived layout sketch is one of a reference to and a copy of the 2D sketch; automatically create a relationship between the first 3D part and a second 3D part by mapping to corresponding respective groupings of sketch entities; and based on the mapping, automatically update at least one of the first 3D part and the second 3D part in the 3D environment relative to a change to a corresponding respective grouping in the 2D sketch.