The type of 3D modeling one needs to create a 3D model depends on the 3D object in question. This 3D object could be a car, a jet, nuts and bolts, and even characters from a movie.
As the name suggests, this type of 3D modeling relies heavily on the object parameters (width, height, breadth, length). It is used to make/ design objects such as a cube, the amount for a motor in a robot or even a car, or a jet, all of which need to be made as per certain size / parametric specifications. You can even purchase 3D models online.
Here the exact measurements take priority in the design process and quick design alterations are possible. This means that parametric modeling is great for design tasks that involve exacting requirements and manufacturing criteria.
Hence, it is used in product design and manufacturing and is typically used by industrial designers.
For example, when companies are looking to make families of products that have slight variations from a core design, parametric modeling is ideal. If one has to make a mount for a motor, first the motor design is mapped out, followed by that of the mount, and then one check — using the CAD software — if the 3D motor model fits well on the 3D mount model.
2. Polygonal/ Direct modeling
This technique of 3D modeling is concept-driven rather than measurement-driven. It’s akin to making something out of clay, where the object depends more on artistic vision than set dimensions. It prioritizes conceptual thinking and feels like sculpting “digital clay”.
It is typically used today in animation and video game industries to create/ design 3D objects such as CGI (computer-generated imagery) movie characters and video game characters (see above).
Here measurements don’t take precedence like in the case of parametric modeling, instead, it’s more about improvisation. A majority of 3D models today are built as textured polygonal models because they are flexible and because computers can render them quickly.