Screwing assembly oriented interactive model segmentation in HMD VR environment

© 2019 John Wiley & Sons, Ltd. Although different approaches of segmenting and assembling geometric models for 3D printing have been proposed, it is difficult to find any research studies, which investigate model segmentation and assembly in head-mounted display (HMD) virtual reality (VR) environments for 3D printing. In this work, we propose a novel and interactive segmentation method for screwing assembly in the environments to tackle this problem. Our approach divides a large model into semantic parts with a screwing interface for repeated tight assembly. Specifically, after a user places the cutting interface, our algorithm computes the bounding box of the current part automatically for subsequent multicomponent semantic Boolean segmentations. Afterwards, the bolt is positioned with an improved K3M image thinning algorithm and is used for merging paired components with union and subtraction Boolean operations respectively. Moreover, we introduce a swept Boolean-based rotation collision detection and location method to guarantee a collision-free screwing assembly. Experiments show that our approach provides a new interactive multicomponent semantic segmentation tool that supports not only repeated installation and disassembly but also tight and aligned assembly

Interpretable Categorization of Heterogeneous Time Series Data

Understanding heterogeneous multivariate time series data is important in many applications ranging from smart homes to aviation. Learning models of heterogeneous multivariate time series that are also human-interpretable is challenging and not adequately addressed by the existing literature. We propose grammar-based decision trees (GBDTs) and an algorithm for learning them. GBDTs extend decision trees with a grammar framework. Logical expressions derived from a context-free grammar are used for branching in place of simple thresholds on attributes. The added expressivity enables support for a wide range of data types while retaining the interpretability of decision trees. In particular, when a grammar based on temporal logic is used, we show that GBDTs can be used for the interpretable classi cation of high-dimensional and heterogeneous time series data. Furthermore, we show how GBDTs can also be used for categorization, which is a combination of clustering and generating interpretable explanations for each cluster. We apply GBDTs to analyze the classic Australian Sign Language dataset as well as data on near mid-air collisions (NMACs). The NMAC data comes from aircraft simulations used in the development of the next-generation Airborne Collision Avoidance System (ACAS X).Comment: 9 pages, 5 figures, 2 tables, SIAM International Conference on Data Mining (SDM) 201

Procedural content creation in VR

3D content creation for virtual worlds is a difficult task, requiring specialized tools based on a WIMP interface for modelling, composition and animation. Natural interaction systems for modelling in augmented or virtual reality are currently being developed and studied, making use of pens, handheld controllers, voice commands, tracked hand gestures like pinching, tapping and dragging mid-air, etc. We propose a content creation approach for virtual reality, placing a focus on making procedural content generation (PCG) intuitive and generalizable. Our approach is to start with a library of 3D assets, with which the user populates an initially empty world by placing and replicating objects individually. The user can then construct procedural rules to automate this process on the fly, creating abstract entities that behave like a block of objects while still being treated and manipulated like other singleton objects. To this end, we design a rule system for procedural content generation adequate for virtual reality, including nested object replication, relative placement and spacing, and randomized selection. We then design and prototype a natural interaction model for virtual reality suited to this rule system, based on two-handed object manipulation, controller input and user voice commands. A prototype of this interaction model is built, and finally, a former user evaluation is conducted to assess its viability and identify avenues for improvement and future work

Brush2Model: Convolution surface-based brushes for 3D modelling in head-mounted display-based virtual environments

Easy and efficient 3D modelling in virtual environments is an important and unsolved topic. This paper proposes a new modelling approach to tackle this issue. It invents convolution surface-based brushes to directly draw 3D models in head-mounted display-based virtual environments. In order to maximize the efficiency, flexibility, and capacity of our proposed modelling approach, we propose three different skeleton-based convolution surfaces to tackle different modelling tasks: point skeleton-based convolution surfaces for metaball shapes, line skeleton-based convolution surfaces for cylindrical shapes, and polygon skeleton-based convolution surfaces for planar surfaces. Their combination makes 3D modelling more flexible and powerful. The high efficiency is further raised by our developed closed-form solutions for point skeletons, ends of line skeletons, and edges of polygonal skeletons. Different user-friendly sweeping schemes are provided to facilitate intuitive inputs for various complex shape generation. Unlike Google's Tilt Brush, which is used to create disconnected sheet-like surfaces only, our proposed convolution surface-based brushes can produce smoothly blended manifold surfaces, and novice users can easily learn and use them to create various interesting 3D models efficiently

A usability study on widget design for selecting boolean operations

Applying the correct set of Boolean operations is a fundamental task in constructive solid geometry (CSG), which is a staple in automated manufacturing systems. Although textual buttons and icons are the most common interfaces to apply such operations, these require an unnecessary cognitive load that hampers the solid modeling process. This study presents VennPad, a novel CSG widget that gathers all Boolean operations under the same user interface control element and is represented as a two-set Venn diagram. Contrary to conventional CSG widgets, VennPad supports a graphical interface that gives simultaneous access to several types of Boolean operations (intersection, union, difference, symmetric difference and split). A usability study was conducted to ascertain whether VennPad is a more natural interface compared to textual buttons and icon-based widgets for different solid modeling tasks. VennPad proved to be an effective interface to perform Boolean operations. Qualitative feedback places VennPad as the preferred interface, but efficiency results are operation dependent, thus, opening the way to new design iterations.info:eu-repo/semantics/publishedVersio

Ride or Die:VR

Treball final de Grau en Disseny i Desenvolupament de Videojocs. Codi: VJ1241. Curs acadèmic: 2018/2019The motivation for the realization of this project arose when I had the idea in my head to adapt conventional skate games to Virtual Reality. Inside my head the idea was quite developed and although there are some existing similar projects, not from the perspective that I want to give to the project. I want to give a pure experience, in first person camera, where the animations submerge the player and make him feel the sensations he can experience with these sports in real life through a video game. The idea of skateboarding was on my mind for quite some time, but I thought that adding Snow and Long tracks would allow me to play with mechanics and add diversity to them

Advanced Transport Operating System (ATOPS) color displays software description: MicroVAX system

This document describes the software created for the Display MicroVAX computer used for the Advanced Transport Operating Systems (ATOPS) project on the Transport Systems Research Vehicle (TSRV). The software delivery of February 27, 1991, known as the 'baseline display system', is the one described in this document. Throughout this publication, module descriptions are presented in a standardized format which contains module purpose, calling sequence, detailed description, and global references. The global references section includes subroutines, functions, and common variables referenced by a particular module. The system described supports the Research Flight Deck (RFD) of the TSRV. The RFD contains eight Cathode Ray Tubes (CRTs) which depict a Primary Flight Display, Navigation Display, System Warning Display, Takeoff Performance Monitoring System Display, and Engine Display

Dynamic system simulation on the web

Computer simulation is the discipline of designing a model of an actual or theoretical physical system, executing the model on digital computer, and analysing the execution output. Of late, simulation has been influenced by an increasingly popular phenomenon - the World Wide Web or WWW. Java is a programming language for the WWW that brings a high level of dynamism to Web applications. Java makes it particularly suitable to represent applications on the Web. It has created an illusion of machine independence and interoperability for many applications. Therefore WWW can be considered as an environment for providing modelling and simulation applications. Research in the area of Web-based simulation is developing rapidly as WWW programming tools develop. Bulk of this research is focused only on discrete event simulation. This dissertation introduces dynamic system simulation on the Web. It presents and demonstrates a Web-based simulation software (SimDynamic), entirely developed in Java, for modelling, simulating, and analysing dynamic systems with 3D animated illustration, wherever applicable. SimDynamic can also be used as a non Web-based application on a PC. In both cases, it supports complete model creation and modification capabilities along with graphical and numerical output. Detail design and functional ability of SimDynamic are provided. Some real world systems have been modeled using SimDynamic and results are presented. Characteristic features of the software are discussed from software engineering point of view. Complete source code and installation instructions are included. Current SimDynamic limitations and potential customization and expansion issues are explored

A survey on personal computer applications in industrial design process

Thesis (Master)--Izmir Institute of Technology, Industrial Design, Izmir, 1999Includes bibliographical references (leaves: 157-162)Text in English, Abstract: Turkish and Englishxii, 194 leavesIn this thesis, computer aided design systems are studied from the industrial designer's point of view. The study includes industrial design processes, computer aided design systems and the integration aspects.The technical issues are priorly studied, including current hardware and software technologies. The pure technical concepts are tried to be supported with real-world examples and graphics. Several important design software are examined, whether by personal practice or by literature research, depending on the availability of the software.Finally, the thesis include a case study, a 17" LCD computer monitor designed with a set of graphic programs including two-dimensional and three-dimensional packages.Keywords: Computers, industrial design methods, design software, computer aided design

LevelEd VR: A virtual reality level editor and workflow for virtual reality level design

Virtual reality entertainment and serious games popularity has continued to rise but the processes for level design for VR games has not been adequately researched. Our paper contributes LevelEd VR; a generic runtime virtual reality level editor that supports the level design workflow used by developers and can potentially support user generated content. We evaluated our LevelEd VR application and compared it to an existing workflow of Unity on a desktop. Our current research indicates that users are accepting of such a system, and it has the potential to be preferred over existing workflows for VR level design. We found that the primary benefit of our system is an improved sense of scale and perspective when creating the geometry and implementing gameplay. The paper also contributes some best practices and lessons learned from creating a complex virtual reality tool, such as LevelEd VR