S S symmetry Article Evolutive 3D Modeling: A Proposal for a New Generative Design Methodology Jaime Nebot , Juan A. Peña * and Carmelo López Gómez Department of Design and Manufacturing Engineering, Engineering Graphics, University of Zaragoza, 50009 Zaragoza, Spain; [email protected] (J.N.); [email protected] (C.L.G.) * Correspondence: [email protected] Abstract: At present, traditional 3D modeling programs consist of a set of tools that reflect con- ventional means of mechanical manufacturing and have limitations in relation with the current manufacturing capacities. On the other hand, organic and morphing 3D modeling programs are designed to transform a model from one known shape to another also known shape. Generative design helps the designers to detach themselves during the design process and can provide them with completely unexpected geometrical solutions. In this paper, starting from 3D morphing techniques and genetic algorithms, a new methodology of product shape definition is developed, capable of imitating processes that occur in nature and aimed at creating new and different product designs. This methodology enables to overcome the limitations imposed by design fixation and allows better exploitation of the great possibilities granted by the new manufacturing techniques, most notably additive manufacturing. The initial process of research and information gathering gives this work a solid basis to develop the new methodology. The results of this initial process are briefly resumed in this paper in order to explain the main motivation for developing this work. The workflow of this methodology is presented as a theoretical process, since its implementation has not been, at least for the moment, put into practice. Before presenting the conclusion for this proposal, several examples Citation: Nebot, J.; Peña, J.A.; have been formulated in order to help the reader to catch the point of the entire process. López Gómez, C. Evolutive 3D Modeling: A Proposal for a New Keywords: evolutive modeling; generative design; design fixation; 3D morphing; genetic algorithms; Generative Design Methodology. geometric modeling; 3D modeling Symmetry 2021, 13, 338. https:// doi.org/10.3390/sym13020338 Academic Editor: José Ignacio Rojas Sola 1. Introduction Received: 3 February 2021 Design fixation deprives designers of a great number of product solutions, thus Accepted: 16 February 2021 affecting the development of the world that surrounds us. For this reason, it is necessary Published: 19 February 2021 to break with the preconceived figures and geometries found during the current design processes, and to find new ways to create structure and shape of products. By doing Publisher’s Note: MDPI stays neutral so, we manage to free the design process from any historic, cultural or conventional with regard to jurisdictional claims in technique influence. published maps and institutional affil- With the emerging manufacturing techniques, especially with additive manufactur- iations. ing, the versatility of product shape is considerably increased, and we should take full advantage of all the potential that these new possibilities offer, breaking with the fixation that exists in the design process when it comes to generating new shapes [1]. In addition, most current 3D modeling software includes design tools geared towards Copyright: © 2021 by the authors. conventional manufacturing. This also implies a diminishing of design freedom when Licensee MDPI, Basel, Switzerland. modeling new products. This article is an open access article In this paper, a new way of facing up to the object modeling and product definition distributed under the terms and needs is developed. A new 3D modeling methodology is proposed, based on generative conditions of the Creative Commons design, in order to help overcome creative fixation derived from the limitations of conven- Attribution (CC BY) license (https:// tional manufacturing techniques. Using 3D morphing tools and genetic algorithms as a creativecommons.org/licenses/by/ basis, a system is developed in which, by imitating the processes of natural evolution, we 4.0/). Symmetry 2021, 13, 338. https://doi.org/10.3390/sym13020338 https://www.mdpi.com/journal/symmetry Symmetry 2021, 13, 338 2 of 12 obtain a series of possible solutions that are different from those that would be reached by designers just through their own creative means. In previous studies, such as the one developed by the authors of [2], a generative system is used in which several results are obtained starting from the initial definition of the general features of a product. In order to obtain these results, different geometric primitives, located in different points of a 3D space, are combined by using operators such as patterns and symmetries. On the other hand, the authors of [3] proposed a generative method that uses tradi- tional CAD technology and genetic algorithms. A base model is created and, by applying random mutations to it, several new models are generated, which will be finally accepted or not according to a series of requirements. In both cases, the techniques used for the shaping of 3D models do limit the results. The reason is that geometric primitive modeling and traditional CAD techniques do not grant as much shaping freedom as polygonal mesh modeling, which enables more organic results. Accordingly, the great advantage of the present proposal over previous studies is the use of a much more abstract initial model and far more organic evolution. This means that the variability of the solutions that are compatible with the product specifications is much larger. Even so, the most notable advance that distinguishes the evolutionary techniques developed so far from the methodology presented in this paper is that the shaping of our products is purely determined by their functional requirements. Furthermore, the evolutionary process we propose is cyclical and iterative, producing far more developed solutions. Consequently, designers can detach themselves during the design process, which is the main goal we seek. Working Method An early stage of search, gathering and analysis of information has provided the necessary basis to establish a solid methodology. Since this paper sums up the process of creating a new methodology from the begin- ning, an important part of the information gathered has been used to define our fields of action, while another important part aimed at the enhancement and reinforcement of our proposal. Other parts focused on how creation and evolution occur in nature, while staying completely free from any kind of influence or fixation. Once all the information was analyzed and filtered, it was used to help to build the new methodology. By taking some of its contents and structuring them adequately, every step of the proposed process was composed. Several alternatives were studied, compared and assessed, until the final definition of this methodology proposal was attained. The results of this process intend to reach the highest possible abstraction level in order to increase the detachment from how a designer would solve the same problem. Therefore, all the considered options to be implemented were assessed according to their level of abstraction, although their feasibility in terms of current and near future computation capabilities was always taken into consideration. Three examples have been proposed in order to better explain the process, since it is, for the moment, theoretical. Two of them have been chosen according to their similarities to the process that is being presented and the third one tries to help understand what exactly we are looking for in this research. 2. Current Works 2.1. Design Fixation The term “fixation” in itself, defines an obsessive interest in a person or object. Based on this term, different concepts applied to more specific situations have evolved. In [4], the term “functional fixedness” is coined. This term refers to the fixation on just one function of a product and, as a consequence, to the mental blocking of any Symmetry 2021, 13, 338 3 of 12 creative reinterpretation of the functions of objects that are familiar to us. Similarly, ref [5] introduces the term “mental-set” or Einstellung effect, referring to a situation in which an individual focuses his/her attention on just one particular process, acting as a block to find different ways to solve a problem. Finally, the term “design fixation” refers to the fixation that can be found in the field of design. In [6], a design exercise is proposed to a group of designers in which, as part of the briefing, examples of solutions are included. The result of the inclusion of the examples is that the capacities of abstraction of the designers are reduced during the design process. This is due to the fact that they unconsciously incorporate into their products properties of the given examples. In this article, the term “design fixation” is used to describe a blind adherence to a limited set of ideas during a design process. As we can see, design fixation has been a case of study for many years and, although it has been applied to different fields and different definitions have been adopted for it, we always encounter, as a common aspect, the fact that it is considered a negative feature. For this reason, the aim of most existing studies is to limit or to correct this phenomenon [7]. Despite having been a case of study for almost a century, there is still much to research regarding this subject [8]. 2.2. Morphing The art of representing shape transformation or morphing has been studied for many years. Currently, 3D morphing techniques are widely used in computer graphics, and we can find them everywhere. In fact, its area of application is large, ranging from special effects animation in the film industry to simulation and representation of medical and scientific processes [9]. The breakthroughs in the morphing techniques that have been made so far are mainly focused on the optimization of the process itself, improving the visualization of the trans- formations and developing interpolation and problem-solving techniques.