As a designer or 3D artist, if you want to make these 3D dolls and pre-views, you must have a certain understanding of 3D Modeling and 3D sculpting techniques. In recent years, the way to make fiberglass dolls is to first use the robot arm 3D sculpting Styrofoam  to make the initial shape. This has many advantages, not only the proportions and the size will be more accurate, the most important thing is time.