The representation of 3D polygonal model on several levels of available detail is a problem inherent in the process of rendering a scene. Highly-detailed models, if placed far from the camera, suffer from spatial aliasing that results from inadequate sampling of their surface, and require disproportionately large amount of time to render. Low-detailed models on the other hand reduce the visual quality of the scene when placed too near to the camera. This report delves in both the theory and the practical techniques used for solving these problems. It describes various published solutions and the principles behind them, and presents a design and an implementation of selected techniques for the GPUEngine library.

The search space of digital 3D models designs is vast and can be hard to navigate. In this study, a system that evolves digital 3D models using an interactive genetic algorithm (IGA) was constructed in order to aid this process. The goal of the study was to investigate how such a system can be constructed in order to aid the design space exploration of digital 3D models.  The system is integrated with the 3D creation suite Blender and uses its Python API to programmatically edit models and generate images of the results, which are displayed on a web page where users can rate the results to evolve the model. The proposed system exposes all settings for the genetic algorithm, which includes population size, mutation rate, crossover algorithm, selection algorithm and more. Furthermore, the settings can be modified throughout the evolutionary process as well as the ability to rewind the algorithm and go back to previous generations in order to give more control in the progression of the algorithm. The script based nature of the proposed system is powerful but not practical for people without programming experience. For widespread adoption of IGAs as an exploratory design aid tool, it would help if the IGA is directly integrated into the design software being used in order to make it easier to use and reduce user fatigue.

The interactions between cells and their microenvironment influence their morphological features and regulate important cellular processes. To understand deleterious neurological disorders such as Parkinson’s disease, there is an immense need to develop efficient in vitro 3D models that can recapitulate complex organs such as the brain. Ultrashort self- assembling peptides offer a revolutionary tool for generating tunable and well-defined 3D in vitro neural tissues capable of recreating complex cellular characteristics, and tissue-level responses. Herein, we describe the use of ultrashort self-assembling peptide-based scaffolds for the development of functional 3D neuronal models including an in vitro model for Parkinson’s disease. Both primary mouse embryonic dopaminergic neurons and human dopaminergic neurons derived from human embryonic stem cells were found biocompatible in our peptide-based models. Using microelectrode arrays, we recorded spontaneous activity in dopaminergic neurons encapsulated within these 3D peptide scaffolds for more than 1 month without a decrease in signal intensity. In addition, we demonstrate a 3D bioprinted model of dopaminergic neurons inspired by the mouse brain using an extrusion-based 3D robotic bioprinting technology. We used our 3D in vitro neuronal models to study the effect of both gabapentin and pregabalin on the development of dopaminergic neurons. Pregabalin and gabapentin are frequently regarded as first-line therapies for a variety of neuropathic pain syndromes, regardless of the underlying cause. Our results showed that both drugs can interfere with the neurogenesis and morphogenesis of ventral midbrain dopaminergic neurons during early brain development. Finally, to gain a better understanding of the influence of cell-cell and cell- matrix interactions on cellular behavior and function in 3D cultured cells within our peptide-based scaffolds compared to the ones cultured in 2D, we studied the metabolic and transcriptomic profiles of 2D and 3D cultured cells. 2D cultured cells exhibited distinct metabolic and transcriptomic profiles compared to the 3D cultured cells. Advancements in the fields of 3D in vitro modeling, 3D bioprinting, and biomaterials are of extreme value for the development of efficient models suitable for investigating disease-specific pathways, aiding the discovery of novel treatments, and promoting tissue regeneration.

No / Online games require small data of 3D models for low storage costs, quick transmission over the Internet, and efficient geometric processing to achieve real-time performance, and new techniques of facial blendshapes to create natural facial animation. Current geometric modelling and animation techniques involve big data of geometric models and widely applied facial animation using linear interpolation cannot generate natural facial animation and create special facial animation effects. In this paper, we propose a new approach to integrate the strengths of ODE (ordinary differential equation) sweeping surfaces and Newton's second law-based facial blendshapes to create 3D models and their animation with small data, high efficiency, and ability to create special facial effects.

Photogrammetry and Structure-from-Motion (S-f-M) is a low-cost method of producing digital 3D models of rock samples that can be used for many different research and educational purposes. A 3D model of a delicate rock sample would enable the preservation of the sample and reduce the need of physical manipulation. This thesis presents a systematic workflow to document and study rock samples by using photogrammetry and S-f-M. The manual in this work describes how to use the set up SOOSI (Spinning Object Optical Scanning Instrument) found at the Department of Earth Sciences at Uppsala University to produce digital 3D models of geological samples. The thesis gives a background to photogrammetry in Earth sciences, and it presents the fundamentals of photogrammetry and the camera. It explains the processing chain of photogrammetry and how computers assist in the photogrammetric process for the reader to understand the importance of the steps in the manual. 3D models produced from following the workflow are presented as well as implications of choices that can be made when following the workflow. The addition of a fixed lens to the camera setup would improve the method’s robustness. The models are currently limited due to a lack of absolute scale. A suggestion for developing a method to capture Ground Control Points (GCPs) to solve the scale problem is presented. / Fotogrammetri och Structure-from-Motion (S-f-M) är en billig metod för att producera digitala 3D-modeller av stuffer som kan användas i olika forsknings- och undervisningssyften. Modeller av stenstuffer minskar behovet av att fysiskt ta i dem och används därför i syfte att bevara ömtåliga stuffer. Denna uppsats presenterar ett systematiskt arbetsflöde för att dokumentera stuffer genom att använda fotogrammetri och S-f-M. Manualen beskriver hur den fotogrammetriska fotostudion SOOSI (Spinning Object Optical Scanning Instrument), som finns på institutionen för geovetenskaper vid Uppsala universitet, används för att producera digitala 3D-modeller. Uppsatsen ger en bakgrund till fotogrammetri inom geovetenskapen och den beskriver kamerans och fotogrammetrins grunder. Vidare förklaras fotogrammetrins bearbetningskedja och hur datorer bidrar i den fotogrammetriska processen för att läsaren ska förstå de olika stegen i manualen. 3D-modeller producerade genom att följa arbetsättet presenteras och de olika val som kan tas när en följer manualen och dess implikationer på resultaten diskuteras. Arbetsättet skulle förbättras om ett objektiv med fast brännvidd införskaffades till fotostudion. 3D-modellernas användningsområde begränsas av att de saknar absolut skala därför presenteras ett förslag till att utveckla arbetsmetoden med hjälp av Ground Control Points (GCP:er).

[pt] Com a chegada da Industria 4.0, empresas aderiram a usar gêmeos digitais para melhorar seus processos de produção e as condições de trabalhos de seus empregados. Os gêmeos digitais são normalmente associados a modelos tridimensionais, permitindo a realização de planejamentos, extração de dados, simulação e treinamento a partir das condições reais. Infelizmente, gêmeos digitais incorretos ou desatualizados podem induzir a erros e a desencontro de informações o que retira todas as vantagens do processo de virtualização, arruinando quaisquer comparativos com a realidade. Em contrapartida, gêmeos digitais ricos em informação permitem que simulações e extrações de dados sejam mais fieis a realidade. Atualmente, as tecnologias capazes de enriquecer as informações de gêmeos digitais são escassos, pois é um procedimento que leva tempo devido a necessidade de análises de especialistas, custos, equipamentos e ferramentas específicas. Recursos como fotografias 360 graus, vídeos e modelos tridimensionais podem ser usados para realizar uma avaliação e atualização nos gêmeos digitais. Porém, diferenças temporais, condições do ambiente e erros humanos entre os recursos podem gerar confusão durante a transferência e conexão da informação. Este trabalho apresenta uma ferramenta que explora as vantagens de combinar fotografias 360 graus com modelos 3D para gerar gêmeos digitais as-built. Cada imagem pode ser ajustada a uma localização dentro do sistema de coordenadas do modelo, inclusive permitindo alterações nos eixos e no campo de visão. Durante a navegação, é possível navegar livremente pelo modelo e pelas posições de interesse criadas pelo usuário. Além da visualização, a ferramenta propõe uma interação mais eficaz para realizar anotações entre modelos e fotografias 360 graus com o propósito de verificar consistências ou agregar novas informações ao gêmeo digital. Estas interações são importantes para a inspeção e manutenção, como avaliação de peças, análise das condições atuais ou a criação de comparativos entre o planejado e o real. / [en] With the arrival of Industry 4.0, companies have adopted digital twins to improve their production processes and the working conditions of their employees. Digital twins are generally associated with three-dimensional models and allow planning, data extraction, simulation, and training based on current conditions. Unfortunately, incorrect or outdated digital twins can lead to errors and information mismatch, which takes away all the advantages of the virtualization and computerization process, ruining any comparisons with reality. In contrast, information-rich digital twins allow simulations and data extraction to be more faithful to reality. Currently, technologies capable of enriching the information of digital twins are scarce, as it is a procedure that takes time due to the need for expert analysis, costs, equipment, and specific tools. Resources such as 360 degrees photographs, videos, and 3D models can be used to perform an evaluation and update the digital twins. However, temporal differences, environmental conditions, and human errors between the images and the model can generate confusion during the transfer and connection of information. This work presents a tool that explores the advantages of combining 360 degrees photographs with 3D models to generate as-built digital twins. Each image can be adjusted to a location within the model s coordinate system, allowing changes to axes and field of view. During navigation, it is possible to navigate the model and the user-created positions of interest freely. In addition to visualization, the tool proposes a more effective interaction to annotate between models and 360 degrees photographs to verify consistency or add new information to the digital twin. These interactions are essential for inspection and maintenance, such as evaluating parts, analyzing current conditions, or creating comparisons between planned and actual.

No description available.

Goals of this work are to summarize the process and existing methods of 3D models watermarking, to choose relevant methods for embedding/extraction of a watermark to/from 3D models. The final solution is based on Spectral Mesh Compression technique. This method is robust, imperceptible and informed. The embedded watermark is detectable and robust against geometrical transformations, added random noise, mesh smoothing and simplification, compression and cropping.  The realized tool allows a user to embedding watermark into the mesh, modify the mesh and extraction of a watermark from mesh. Testing was conducted on a set of 5 models differing in size, shape and density of points. The resulting tool inserts a watermark composed of four characters that can detect both undamaged models and the models affected. Among the attacks against which the watermark is robust, include transformations, rotation, scale, adaptive random noise, and combination of this.

3D reconstruction can be used in forensic science to reconstruct crime scenes and objects so that measurements and further information can be acquired off-site. It is desirable to use image based reconstruction methods but there is currently no procedure available for determining the uncertainty of such reconstructions. In this thesis the uncertainty of Structure from Motion is investigated. This is done by exploring the literature available on the subject and compiling the relevant information in a literary summary. Also, Monte Carlo simulations are conducted to study how the feature position uncertainty affects the uncertainty of the parameters estimated by bundle adjustment. The experimental results show that poses of cameras that contain few image correspondences are estimated with higher uncertainty. The poses of such cameras are estimated with lesser uncertainty if they have feature correspondences in cameras that contain a higher number of projections.

No description available.