# Design for Additive Manufacturing: Tool Review and a Case Study
## 3 Additive Manufacturing Design Tools  
In order to take advantage of and mitigate the limitations of these AM processes, different tools have appeared in recent years that maximize the potential of the constructive capabilities offered by additive manufacturing technologies. These programs consist of engineering and CAD platforms such as mesostructured design and optimization programs, along with process management and simulation solutions. One of the main objectives set in the development of this work is to configure an updated workflow, ordered and structured to optimize processes from the integration and exchange of files, as well as to maximize the potential of the possibilities of forming that AM technologies present, supported by these specific tools. In Figure 2 is presented different CAD and computer-aided engineering (CAE) tools currently available for the AM design process. Some of these programs previously existed on the market and have been adapted to these technologies, as well as other new specific tools that are appearing as the development and implementation of them advance. Within the software tools, in addition to the traditional CAD programs, such as parametric design programs, e.g., Catia and Solidworks (Dassault Systemes, Velizy-Villacoublay, France), Inventor (Autodesk, San Rafael, CA, USA) or NX (Siemens, Munich, Germany), we have to consider expanding the range of tools. Thanks to the design freedom offered by layer-by-layer construction in the AM technologies, which allows us to shape virtually any geometry, we must add other surface design tools, which include the above programs, and other new ones such as Rhino (Robert McNeel & Associates, Seattle, WA, USA) or Alias and 3D Studio (Autodesk, San Rafael, CA, USA). AM allows us to create objects with organic shapes and geometric complexity without a great impact on the cost or complexity of manufacturing. This freedom already existed in digital design for animation or video games, while CAD software traditionally associated with mechanical design had limited capabilities. Although in the latest versions of the abovementioned CAD software, the possibility of making complex geometries more easily has already been implemented, certain specialized software is still required. These programs usually work with 3D design tools based on NURBS or editable polygonal mesh that allow a freer and more organic design without limitations when generating geometries or parts. Another trend in AM is the use of optimization software, based on developments that have had more than 20 years of use in the industry, however, they have never had an extensive use, because the solutions they provide, in geometric terms, are always very complex and traditional production processes for machining or casting did not meet the requirements for proper production. However, with the emergence of AM technologies and their layer-by-layer production systems, these geometries resulting from different optimizations, whether volumetric, shape or topological, as schematized in Figure 3, are perfectly achievable. The optimization tools determine formal solutions to different requirements through the application of numerical models in iterative processes, based on different calculation algorithms of shape, volume or load [24], trying to obtain ideal solutions with respect to the geometries of the parts. Among the most widespread tools in the processes of AM, we must highlight the topological optimization (TO). In this type of tool, starting from some established objectives (usually minimizing mass or maximizing rigidity) and some requirements of load and restrictions of design, an orientated solution adapted to the defined objectives is obtained. The solutions provided by this tool serve as a reference shape of the part designs.