From 3D Models to 3D Prints: an Overview of the Processing Pipeline

Due to the wide diffusion of 3D printing technologies, geometric algorithms for Additive Manufacturing are being invented at an impressive speed. Each single step, in particular along the Process Planning pipeline, can now count on dozens of methods that prepare the 3D model for fabrication, while analysing and optimizing geometry and machine instructions for various objectives. This report provides a classification of this huge state of the art, and elicits the relation between each single algorithm and a list of desirable objectives during Process Planning. The objectives themselves are listed and discussed, along with possible needs for tradeoffs. Additive Manufacturing technologies are broadly categorized to explicitly relate classes of devices and supported features. Finally, this report offers an analysis of the state of the art while discussing open and challenging problems from both an academic and an industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and Innovation action; Grant agreement N. 68044

Comparing Slicing Technologies for Digital Light Processing Printing

In additive manufacturing (AM), slicing is a crucial step in process planning to convert a computer-aided design (CAD) model to a machine-specific format. Digital light processing (DLP) printing is an important AM process that has a good surface finish, high accuracy, and fabrication speed and is widely applied in many dental and engineering industries. However, as DLP uses images for fabrication different from other toolpath-based processes, its process planning is understudied. Therefore, the main goal of this paper is to study and compare the slicing technologies for DLP printing. Three slicing technologies are compared: contour, voxelization, and ray-tracing

Feature-based design of solids with local composition control

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 2004.Includes bibliographical references (leaves 126-134).This thesis presents a parametric and feature-based methodology for the design of solids with local composition control (LCC). A suite of composition design features are conceptualized and implemented. The designer can use them singly or in combination, to specify the composition of complex components. Each material composition design feature relates directly to the geometry of the design, often relying on user interaction to specify critical aspects of the geometry. This approach allows the designer to simultaneously edit geometry and composition by varying parameters until a satisfactory result is attained. The identified LCC features are those based on volume, transition, pattern, and (user-defined) surface features. The material composition functions include functions parametrized with respect to distance or distances to user-defined geometric features; and functions that use Laplace's equation to blend smoothly various boundary conditions including values and gradients of the material composition on the boundaries. The Euclidean digital distance transform and the boundary element method are adapted to the efficient computation of composition functions. Theoretical and experimental complexity, accuracy and convergence analyses are presented. The developed model is a multi-level and graph-based representation, thereby allowing for controls on the model validity and efficiency in model management. The representations underlying the composition design features are analytic in nature and therefore concise. Evaluation for visualization and fabrication is performed only at the resolutions required for these purposes, thereby reducing the computational burden.by Hongye Liu.Ph.D

Software tectonics

Thesis (Ph. D. in Design and Computation)--Massachusetts Institute of Technology, Dept. of Architecture, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 365-370).The resent shift of attention in the architectural discourse towards issues of ecological design, coupled with the undeniable role of computation, has already cast a new operative role to the notion of environment. Instead of being the passive, conceptualized or historicized context of an architectural object, environment is quite literally becoming the object of design itself. We are moving away from the imposed-preconceived Cartesian object which negotiates through its boundaries its presence within its immediate context. The discipline is already considering an architecture in which architectural form is only an instance of a designed environment. In many respects, this new understanding of environment aspires to be actively designed as a closed system of constant transformation, an autonomous milieu of exchange at all scales and all levels between substances, properties or qualities. The object of investigation in Software Tectonics is how technologies of design and construction allow newly forming propositions about the role of environment in the discipline to become operational tactics in the design practice. SOFTWARE TECTONICS proposes 3 design research projects. VSpace is a computer drawing application for designers. Unlike traditional CAD systems that work primarily by representing boundaries (B-reps), VSpace derives form by the representation and direct manipulation of properties (P-reps) in space. Boundaries and Properties here are considered simultaneously in the same design environment. Castit is a multi axis, Computer Numerically Controlled device that prints 3D objects by dynamically mixing at least two distinct but chemically compatible materials. Dynamic mixing allows for gradient transitions between two or more materials, resulting in objects with anisotropic material properties. CHUNK aims to eliminate a joint as a third mediating member between two building elements with an area of gradient transition. Conceived as a "dynamic insulation" architectural skin, this building technology project challenges the multi-trade and multi-component tectonics of dominant late-industrial building manufacture.by Alexandros Tsamis.Ph.D.in Design and Computatio

Voronoi diyagramına dayalı bir yörünge planlama ve güncelleme algoritması

Coverage of an area is required for a large variety of robotics and manufacturing applications, such as environment monitoring, home cleaning, search and rescue operations, machining, delivery, additive manufacturing and even for 3D terrain reconstruction. In this work, we present a highly flexible algorithm that can be used for coverage and graph traversal. In addition to being applicable to diverse types of engineering problems, proposed method is advantageous to other algorithms, as it never turns around and traverses the edge it recently traversed. Although the method takes advantage of variable-sized Voronoi cells, by which regular, irregular and complex geometries can be easily composed, it is not limited to Voronoi diagrams and can be applied for any connected graph. Furthermore, path planning algorithm can update the path to deal with changes in the graph. In some applications, like 3D printing, path planning must be done for many instances. However, our algorithm calculates the path at the first layer, and performs only necessary changes at the subsequent layers, instead of calculating the whole path from scratch. This update mechanism makes the method very efficient as it is demonstrated with several test cases. In addition to the path planning algorithm, a G-code file encryption method is introduced, size of G-code files can be greatly reduced. As automation and robotics integrate into numerous areas everyday, proposed methods can be useful for many applications.Alan tarama işlemi robotik ve üretim alanlarında birçok uygulama için gereklidir. Çevreyi gözetlemek, ev temizligi, arama ve kurtarma operasyonları, parça işleme, teslim ve 3B arazi rekonstrüksiyonu buna örnek olarak verilebilir. Bu çalı¸smada, alan ve grafik tarama uygulamarında kullanılabilecek ve son derece esnek bir algoritma sunulmuştur. Farklı alanlarda birçok probleme uygulanabilir olmanın yanı sıra, algoritmanın diger yakla¸sımlardan üstün özellikleri bulunmaktadır. Örneğin, taramakta oldugu kenarı tekrar taramak yerine başka bir kenara devam etmektedir. Geliştirilen yöntem, düzenli ve düzensiz kafes yapılarını modellemek için rahatlıkla kullanılabilecek Voronoi hücrelerinden faydalanmaktadır. Öte yandan, yöntem yalnızca Voronoi grafikleriyle kısıtlı olmayıp herhangi bir baglı grafiğe de uygulanabilir. Algoritma, yörünge planlama dı¸sında, yörünge güncelleme özelligine de sahiptir. 3B üretim gibi, onlarca katman boyunca yörünge planlamanın gerekli olacagı bir senaryoda, algoritma ilk katman için bir yörünge planı oluşturup devam eden katmanlar için bu yörüngeyi güncellemektedir, her katmanda yörüngeyi baştan planlamamaktadır. Testlerle de gösterildigi üzere, bu planlama mekanizması algoritmayı son derece verimli yapmaktadır. Yörünge planlama dışında, G-kodu dosyalarıyla aynı veriyi çok daha az bir depolama alanıyla saklayan bir yöntem sunulmuştur. Otomasyon ve robotik teknolojilerinin sayısız alanda kullanılmasıyla birlikte sunulan yöntemler birçok uygulama için kullanışlı olacaktırM.S. - Master of Scienc

Design and development of a VR system for exploration of medical data using haptic rendering and high quality visualization

[no abstract

Detection of geobodies in 3D seismic using unsupervised machine learning

In this work, we present a novel, automated method for detecting geobodies in 3D seismic reflection data, helping to reduce interpreter bias and speed up seismic interpretation. A seismic geobody refers to a geometrical, structural, or stratigraphic feature, such as a channel, turbidite fan, or igneous intrusion. Geobodies are subtle seismic features, hard to pick, and their detection is challenging to automate due to their complex 3D geomorphology and diversity of shapes. Nevertheless, the detection and delineation of these structures are essential for improving the understanding of the subsurface as well as building a variety of conceptual models. In our approach, we can rapidly interpret large 3D seismic volumes using point cloud-based segmentation to identify geobodies of interest, including complex stratigraphic features like lobes and channels. By converting the 3D seismic cube into a 3D seismic point cloud (sparse cube), we reduce the volume of data to analyse, which in turn speeds up the detection process. First, we build the 3D point clouds by filtering the seismic reflection volume using different seismic attributes, and then each point in the cloud is segmented into different clusters. The clustering is performed using the unsupervised Density-Based Spatial Clustering of Applications with Noise (DBSCAN) which allows the segmentation of all structures present into delineated objects. The clustered objects can then be characterised by features based on their 3D shape and spatial amplitude distribution. Finally, our method allows the selection of a specific geobody and can retrieve geobodies based on their similarity to exploration targets of interest. The method has been applied successfully to two modern 3D seismic datasets (Falkland Basins) and two types of geobodies: fans and sill intrusions. We demonstrate that our method can scan through a large 3D seismic volume and automatically retrieve likely fan and sill geobodies in a very efficient manner. This approach can be used to scan through large volumes of 3D seismic, looking for a wide variety of geobodiesJames Watt Scholarshi

Simple identification tools in FishBase

Simple identification tools for fish species were included in the FishBase information system from its inception. Early tools made use of the relational model and characters like fin ray meristics. Soon pictures and drawings were added as a further help, similar to a field guide. Later came the computerization of existing dichotomous keys, again in combination with pictures and other information, and the ability to restrict possible species by country, area, or taxonomic group. Today, www.FishBase.org offers four different ways to identify species. This paper describes these tools with their advantages and disadvantages, and suggests various options for further development. It explores the possibility of a holistic and integrated computeraided strategy