Master Thesis

Title: Optimal rotations for overhang reduction.
Advisor: Dr. Leonardo Sacht (site)
Abstract: 3D printing is gaining ground in many areas around the world, being used in construction, modeling and mockups, educational purposes and for health research, as well as in the printing of body parts for surgery assistance. When the printer needs to print a 3D surface, some of the parts may be suspended in the air, requiring support for better printing. These supports are detached from the object and are discarded, generating waste of material and money. This thesis proposes a new approach for this problem of 3D surface printing based on the normal field of surfaces, which seeks a global surface orientation, so that, after rotating the surface by the obtained orientation, its printing generates as less support as possible.
Keywords: 3D printing, normal field, support, overhang, optimization.
     

Undergraduate Dissertation (pt-br)

Title: Image reconstruction methods applied to audio signals.
Advisor: Dr. Leonardo Sacht (site)
Abstract: Within the area of musical information retrieval, this paper aims to investigate the results of the main image reconstruction methods in their applications to audio signals, in addition to seeking to understand the main results behind these mecanisms. Thus, we seek to build a theorical basis with the objective of structuring the concepts of Fourier transform and convolution for the treatment of these methods, which are inserted in the pipeline for images sampling and reconstruction. Besides that, analyses will be held on the methods used in order to evaluate which one acts more efficiently on sound treatment. Among the results obtained, it was noticed that the best image reconstruction methods applied to sound vary depending on the sound type we want to reconstruct.
Keywords: Image reconstruction; Audio Signals; Music Information Retrieval; Fourier Transform; Convolution.
     

Title: Normal transformations for overhang reduction
DOI: 10.5753/sibgrapi.est.2019.8316
Authors: Carlos Eduardo Leal de Castro, Leonardo Koller Sacht
Abstract: We present a partial solution for the problem of reducing overhanging parts of a surface to 3D print it with minimal number of supports. We first present a summary about how a 3D printer works and why the overhanging problem happens. This review focuses on a specific type of 3D printer that uses polymer melted to print solids on cross-sectional layers. We then do a fast review of three-dimensional surface representation in a computer and its discrete representation. Then we present our minimization problem and show some test results, using libigl library and gptoolbox functions, to observe the solution of problem.
Keywords: 3D printing, normal transformations, overhang, optimization.
Publication: SIBGRAPI - Workshop of Works in Progress.
Year: 2019
     

Title: The value geometric drawing language for teaching of geometry (pt-br)
Author: Carlos Eduardo Leal de Castro
Abstract: This paper seeks to present the formation sequence of math and geometric drawing languagem curriculum, indicating its peak and the main reasons for decadence. Furthermore, presets arguments to advocate the inclusion of geometric drawing language on geometry teaching, based mainly on researches with elementary and high school students. Finally, it presents new perspectives on geometry teaching with the advancement and inclusion of technology in mathematics.
Keywords: geometric drawing language, math, teaching, curriculum.
Publication: Revista da Olimpíada Regional de Matemática de Santa Catarina, n. 15, 2018 (link)
ISSN: 1679-7612
Year: 2018.