As widely recognised, the term aesthetics is related to both what the product presents to the senses (especially vision) and the process of regarding an object [1]. In contrast, functionality indicates how a product can serve its goal [2] by ensuring a set of required mechanical/technical properties, under specific constraints. Since a product’s success is commonly correlated with its capacity to strike an ideal balance between aesthetics and functionality, these two seemingly opposite concepts must find a meeting point during product design and production. For the aesthetic designer, developing a novel product and considering its functionality is like playing solitaire with cards: often there is no counterpart as in other projects and furthermore, there is no dialectical relationship with the customer, the engineer or the technologist. The creative person is “alone with himself” and required to set the rules of the game, drawing from their own reservoir of skills, not necessarily complying with engineering design and manufacturing. This is what makes the designer’s game more challenging, but also more exciting [3], especially when creativity and stylistic innovation are predominant in the creation of the product. However, this kind of design methodology is an exception, defining only a tiny fraction of the whole design industry and typically being restricted to the creation of luxury goods [4]. The search for an original, iconic, and distinctive design represents, in these cases, the main interest of the company, which is willing to give up many technical compromises in order to ensure a unique product capable of adding value to the entire brand.

In reality, in most cases, the designer is forced to confront a series of constraints dictated by all the technological aspects that must be considered when designing a successful product. These include the need to imagine a product that is able to respect functional requirements without sacrificing aesthetics at the same time [5], such as the manufacturability of the components, competitiveness in terms of performance compared to the competition, scalability of production, and the need to reduce costs.

All these elements contribute in different weights to the success of the product and must be integrated as organically as possible within it. Ultimately, to ensure a high value of the product imagined by the designer, the design activity must be able to integrate the concept design, where forms, layouts, operating principles, and sensory, perceptive and emotional properties are defined, with the embodiment and detailed design phases where technical acts such as construction drawings, models, choice of materials, and choice of production process impact on the final realisation. In the best-case scenario, the aesthetics of the product should lead to the definition of forms that also reinforce the technical aspects and are of interest to a buyer. The realisation of forms that, while iconic, are easily produced with either traditional technological processes or the most modern 3D printing tools, leading to material savings, or capable of significantly improving the performance of the object studied, is an established goal for the modern designer.

In large companies, characterised by major brands, the synthesis of these several aspects of product planning is achieved through the integration of dedicated teams characterised by very different profiles of experience and skills. Through concurrent planning [6], i.e., an organic set of methodologies, techniques, and tools that allows an integrated approach to the design of a product and its production process, it is possible to effectively achieve the desired objective.

The case of significantly smaller realities is different. Smaller design studios, individual aesthetic designers, and planners must be able to conduct the described synthesis process without being able to draw on the different experiences of a team of specialists in different fields. In this context, the experience of the aesthetic designer, together with their creativity, is the main driver towards a successful solution. Unfortunately, given the vastness of design activities, the building of a personal wealth of knowledge is in any case a complex and prolonged activity, which cannot, over time, keep up with the demands of product innovation in view of the development trend offered by the state of the art.

The design education of new industrial designers must clearly aim for the formation of a critical spirit, the construction of a design methodology, and the definition of a unique style [7]. At the same time, however, the training must provide for the transmission of a set of basic technical skills, which the designer can draw on to assess the manufacturing and functional aspects of the product, as well as the tools and methods necessary to manage the value chain in the innovation aspects of industrial design and related processes. Technical drawing, mechanical technology, design under static and dynamic loads, evolutionary design, product end-of-life management, and circular economy [8] are the main aspects that every designer should include in their knowledge from the very beginning of their career.

In the absence of an adequate level of technical background, the search for this synthesis is characterised as the greatest difficulty for young aesthetic designers who have not yet accrued a wealth of skills to guide them in functional design. For this reason, the search for concrete solutions, in which the aspects of manufacturability, structural, and other accessory functions (interface with man, ergonomics, and usability) are often hindered by the definition of forms that are difficult to concretise and linked in the foreground to aesthetic aspects alone. This phenomenon is stimulated by the introduction of surface modellers, which do indeed leave the user great freedom in defining complex and interesting geometries, shapes, and topologies, but do not allow aspects relating to the functionality and actual realisability of the product to be assessed in advance. Secondly, despite the propensity of young design students to use smart technologies, the “disconnection” between digital design and effective manufacturability of the conceived product has introduced new barriers and exacerbated the gap described above.

The range of CAD modelling software currently available on the market is diversified. By analysing the various CAD modelling systems, it is possible to identify significant differences in the operating logic and performance offered to the user. As widely recognised, the main distinction that can be made is between non-parametric and parametric CAD systems. The former does not consider the temporal succession of operations made by the user to arrive at the desired result (which is identified in the modelling history of the model). The latter, on the other hand, does keep track of this type of data. Traditionally, the term ”parametric modelling” refers to CAD logic that keeps track of the modelling functions used by the user and the relationships and constraints imposed. Conversely, “non-parametric” modelling only considers the last configuration of the digital model modified by the user and allows interaction with this, but not with the models resulting from previous operations.

Both strategies present advantages and disadvantages: on a general level, non-parametric modelling is usually more intuitive, requires less knowledge of the modelling environment within which one moves, and is easier to manage by the software, which does not have to keep track of many parameters and relationships, only of the final result. At the same time, however, the user has no access to the modelling history of the object and can only interact with its final instance. Modelling functions are usually less advanced [10].

Parametric modelling, on the other hand, imposes a complex management of relationships between modelled geometric features: the software must keep track of the temporal succession of operations, geometric constraints, dependencies between features, and dimensional parameters set by the designer. All these elements are introduced by the user through the graphic interface and interpreted by the software through a system of mathematical equations, which becomes increasingly complex as the number of relations entered increases. This information management system allows the user to freely modify any function used during modelling. All operations performed by the user remain accessible within the so-called “feature tree”, an element of the graphic interface that collects them in chronological order.

Parametric modellers are also the CAD systems that come closest to the worlds of industry and manufacturing. Many of the modelling functions that can be selected within these systems directly invoke manufacturing processes (e.g., extrusion); consequently, the shapes generated by these functions maintain a link with manufacturing processes [10]. As widely known, the basic modelling approach in parametric systems starts with the construction of a two-dimensional (2D) sketch on a model reference plane. The 3D modelling algorithms that analyse this graphic element’s geometry to create three-dimensional surfaces or solids utilise it as fundamental data. These forms remain linked to the basic sketch that created them and are affected dynamically by any changes to it. The shapes generated thus remain linked to their two-dimensional representation, reinforcing the link between modelling and drafting.

The possibility of modifying geometrical relationships and dimensions lends itself particularly well to industrial designs. If during the preliminary design phase, the designer’s objective is to attain a concept that conveys the idea and style of the product as quickly as possible, as the design activity proceeds, shapes and dimensions are defined through detailed design. At this stage, the ability to modify the structure of the generated model is a fundamental value, saving time and reducing design costs. Such changes will be effective and intuitive if the original modelling has been conducted effectively. If the modelling is well executed, the shape of the designed object should be determined by geometric constraints; thus, by changing a few dimensional parameters, different versions of the same topology can be obtained. An example is shown in Figure 2, where a solid, defined by a single modelling history, is represented in four different configurations as the control parameters change.