Design of Virtual Objects for Exact Collision Detection in Virtual Reality Modeling of Manufacturing Processes

1998 ◽  
Author(s):  
Rade Tesic ◽  
Pat Banerjee
Keyword(s):  
Virtual Reality ◽  
Collision Detection ◽  
Near Miss ◽  
Manufacturing Processes ◽  
Interactive Simulation ◽  
Robotic Welding ◽  
Virtual Objects ◽  
Detection Algorithms ◽  
Surface Patches ◽  
Slow Progress

Abstract Collision detection becomes a key issue when we want to model interactions between general, nonconvex objects in virtual reality applications which arise in manufacturing process domain. Despite significant progress which has been made in developing efficient, exact collision detection algorithms for convex objects, limited and slow progress has been reported in developing collision detection algorithms for general, nonconvex objects. To narrow this gap we introduce a concept of virtual objects which extends applicability of exact collision detection algorithms to nonconvex objects. This paper presents a methodology to encapsulate into virtual objects the surface patches of interest for collision detection as well as the automatic procedures for creation of virtual objects and for partitioning them into convex pieces. The collision detection technique described in this paper is best suited for interactive simulation and animation applications where high accuracy of object contact modeling is required. Examples include virtual assembly; mobile robot simulation; and simulation of manufacturing processes where accurate modeling of near-miss detection is essential, e.g. robotic painting, robotic welding, and NC machining operations.

Collision Detection

2011 ◽  
pp. 36-67
Author(s):  
Gabriel Zachmann
Keyword(s):  
Virtual Reality ◽  
Real Time ◽  
Collision Detection ◽  
Serious Games ◽  
Medical Training ◽  
Virtual Assembly ◽  
Virtual Objects ◽  
Enabling Technologies ◽  
Assembly Simulation ◽  
Physically Based

Collision detection is one of the enabling technologies in many areas, such as virtual assembly simulation, physically-based simulation, serious games, and virtual-reality based medical training. This chapter will provide a number of techniques and algorithms that provide efficient, real-time collision detection for virtual objects. They are applicable to various kinds of objects and are easy to implement.

3D Object Representation for Physics Simulation Engines and its Effect on Virtual Assembly Tasks

2012 ◽  
Author(s):  
Germanico Gonzalez ◽  
Hugo I. Medellin ◽  
Theodore Lim ◽  
James M. Ritchie ◽  
Raymond C. W. Sung
Keyword(s):  
Collision Detection ◽  
Object Representation ◽  
Virtual Assembly ◽  
Detection Algorithm ◽  
Convex Decomposition ◽  
Virtual Objects ◽  
Detection Algorithms ◽  
Physics Simulation ◽  
Assembly Tasks ◽  
Simulation Engines

Physical based modelling (PBM) uses physics simulation engines (PSE) to provide the dynamic behaviour and collision detection of virtual objects in virtual environments emulating the real world. There exists a variety of PSEs, each one with pros and cons according to the application in which they are employed. Each physics engine uses its proprietary collision detection algorithm. Collision detection is a key aspect of assembly tasks and its performance is dependent on the way virtual objects are represented. In general, objects can be divided into two groups: convex and concave, the latter being the most common and challenging for collision detection algorithms. This study reports on three different methods to represent concave objects. GIMPACT, Hierarchical Approximate Convex Decomposition (HACD) and Approximate Convex Decomposition (ACD), which are evaluated and compared based on their collision detection performances. An exact convex decomposition algorithm, named as ConvexFT, is also proposed and analyzed in this paper. Finally the performance of the three existing methods and the ConvexFT proposed approach are compared in order to assess which model representation algorithm is best suited for haptic-virtual assembly tasks.

scholarly journals User-Defined Gestures with Physical Props in Virtual Reality

2021 ◽  
Vol 5 (ISS) ◽  
pp. 1-23
Author(s):  
Marco Moran-Ledesma ◽  
Oliver Schneider ◽  
Mark Hancock
Keyword(s):  
Virtual Reality ◽  
Physical World ◽  
Virtual Objects ◽  
Open World ◽  
Elicitation Study ◽  
Agreement Score ◽  
Small Set ◽  
Elicitation Studies ◽  
Context Free ◽  
Context Free Grammars

When interacting with virtual reality (VR) applications like CAD and open-world games, people may want to use gestures as a means of leveraging their knowledge from the physical world. However, people may prefer physical props over handheld controllers to input gestures in VR. We present an elicitation study where 21 participants chose from 95 props to perform manipulative gestures for 20 CAD-like and open-world game-like referents. When analyzing this data, we found existing methods for elicitation studies were insufficient to describe gestures with props, or to measure agreement with prop selection (i.e., agreement between sets of items). We proceeded by describing gestures as context-free grammars, capturing how different props were used in similar roles in a given gesture. We present gesture and prop agreement scores using a generalized agreement score that we developed to compare multiple selections rather than a single selection. We found that props were selected based on their resemblance to virtual objects and the actions they afforded; that gesture and prop agreement depended on the referent, with some referents leading to similar gesture choices, while others led to similar prop choices; and that a small set of carefully chosen props can support multiple gestures.

scholarly journals Efficient n-to-n Collision Detection for Space Debris using 4D AABB Trees

10.29007/5pl1 ◽  
2019 ◽  
Author(s):  
Stanley Bak ◽  
Kerianne Hobbs
Keyword(s):  
Collision Detection ◽  
Space Debris ◽  
Dynamics Simulation ◽  
Video Gaming ◽  
Time Dimension ◽  
Detection Algorithms ◽  
Space Objects ◽  
Tree Data ◽  
Tree Data Structure ◽  
Three Space

Collision detection algorithms are used in aerospace, swarm robotics, automotive, video gaming, dynamics simulation and other domains. As many applications of collision detection run online, timing requirements are imposed on the algorithm runtime: algorithms must, at a minimum, keep up with the passage of time. Even offline reachability computation can be slowed down by the process of safety checking when n is large and the specification is n-to-n collision avoidance. In practice, this places a limit on the number of objects, n, that can be concurrently tracked or verified. In this paper, we present an improved method for efficient object tracking and collision detection, based on a modified version of the axis-aligned bounding-box (AABB) tree data structure. We consider 4D AABB Trees, where a time dimension is added to the usual three space dimensions, in order to enable per-object time steps when checking for collisions in space-time. We evaluate the approach on a space debris collision benchmark, demonstrating efficient checking beyond the full catalog of n = 16848 space objects made public by the U.S. Strategic Command on www.space-track.org.

scholarly journals Ensino das Ciências Imerso em Ambientes Virtuais Multiusuários

2019 ◽  
Vol 20 ◽  
pp. 345-351
Author(s):  
Marisa Pascarelli Agrello ◽  
Marianina Impagliazzo ◽  
Joaquim José Escola
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Science Teaching ◽  
Present Article ◽  
Learning Objects ◽  
Educational Technologies ◽  
Virtual Objects ◽  
The World ◽  
Practical Experiences

ResumoNo presente artigo apresentamos a experiência realizada com o uso dos softwares de realidade aumentada (RA) e a realidade virtual (RV) em cenários para o Ensino das Ciências objetivando atender a Era da Educação 4 por meio de manipulação de objetos virtuais.Com aplicações distintas, as duas tecnologias são complementares e se configuram como ferramentas adicionais aos docentes com a proposta de elevar a qualidade das aulas e a geração de uma aprendizagem significativa representando uma ponte entre a educação e a tecnologia. Como objetos virtuais de aprendizagem (OVA), deverão ser usados em sala de aula como forma de enriquecimento das experiências práticas por meio da representação virtual de temas e contextos tornando mais ativa, contextualizada e efetiva o processo de apreensão do mundo. Palavras-chave: realidade virtual, realidade aumentada, ensino das ciências, tecnologias educacionais. Abstract In the present article we present the experience with the use of software of augmented reality (RA) and virtual reality (VR) in scenarios for the Teaching of Sciences in order to attend the Age 4 of Education through manipulation of virtual objects, the two technologies are complementary and are configured as additional tools for teachers with the proposal of raising the quality of lessons and generating meaningful learning as a bridge between education and technology. As virtuais learning objects, they should be used in the classroom as a way to enrich practical experiences through virtual representation of themes and contexts, making the process of apprehension of the world more active, contextualized and effective. Keywords: virtual reality, augmented reality, science teaching, educational technologies.

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