Virtual Reality Environment for Creation of Freeform Models

Manufacturing ◽  
2002 ◽  
Author(s):  
Bilal Y. Maiteh
Keyword(s):  
Virtual Reality ◽  
Physical Environment ◽  
Hand Movements ◽  
Virtual Reality Environment ◽  
Mathematical Algorithm ◽  
Virtual Tools ◽  
Solid Models ◽  
Swept Volumes ◽  
Novel Method ◽  
Virtual Workpiece

A novel method has been developed using a virtual reality (VR) environment to create solid models with freeform surfaces. The VR environment emulates the physical environment for creating freeform objects, i.e. the freeform model is created in a virtual environment by shaping a virtual workpiece with a variety of virtual tools. The trajectories of the virtual tools are generated by the designer’s hand movements and they are obtained by recording the position and orientation of the motion tracker mounted on a device held by the hand. In the mathematical algorithm, the swept volumes of the design tools are computed from the tools’ geometric data and trajectories. Boolean operations are then performed on the swept volumes of the virtual tools and the virtual workpiece to create the design model.

Solid Modelling Through Constraint-Based Manipulations in a Virtual Reality Environment

2002 ◽  
Author(s):  
Yongmin Zhong ◽  
Wolfgang Mu¨ller-Wittig
Keyword(s):  
Virtual Reality ◽  
Data Model ◽  
Natural Extension ◽  
Constraint Solving ◽  
Prototype System ◽  
Solid Modelling ◽  
Virtual Reality Environment ◽  
Solid Models ◽  
Intuitive Manner ◽  
Incorporation Method

Virtual Reality (VR) technology is a natural extension of 3D computer graphics with advanced input and output devices and brings a completely new environment to the CAD community. However, with today’s VR systems, it is difficult to directly and precisely create and modify objects in a VR environment. This paper presents an efficient approach for solid modelling in a VR environment. Solid modelling in the VR environment is precisely performed in an intuitive manner through precise constraint-based manipulations. Constraint-based manipulations are accompanied with automatic constraint recognition and precise constraint satisfaction for establishing the hierarchically structured constraint-based data model and are realized by allowable motions for precise 3D interactions in the VR environment. The allowable motions are represented as a mathematical matrix for conveniently deriving the allowable motions from constraints. A procedure-based degree-of-freedom incorporation method for 3D constraint solving is presented for deriving the allowable motions. A rule-based constraint recognition engine is developed for automatic constraint recognition. A prototype system has been developed for solid modelling in the VR environment, where the user can create solid models in an intuitive manner through precise constraint-based manipulations.

Top-Down Processing and Visual Reorientation Illusions in a Virtual Reality Environment

2004 ◽  
Vol 63 (3) ◽  
pp. 143-149 ◽  
Author(s):  
Fred W. Mast ◽  
Charles M. Oman
Keyword(s):  
Virtual Reality ◽  
Visual Processing ◽  
Line Length ◽  
Perceptual Cues ◽  
Virtual Reality Environment ◽  
Top Down ◽  
Test Conditions ◽  
The Subject ◽  
Processing Mechanisms

The role of top-down processing on the horizontal-vertical line length illusion was examined by means of an ambiguous room with dual visual verticals. In one of the test conditions, the subjects were cued to one of the two verticals and were instructed to cognitively reassign the apparent vertical to the cued orientation. When they have mentally adjusted their perception, two lines in a plus sign configuration appeared and the subjects had to evaluate which line was longer. The results showed that the line length appeared longer when it was aligned with the direction of the vertical currently perceived by the subject. This study provides a demonstration that top-down processing influences lower level visual processing mechanisms. In another test condition, the subjects had all perceptual cues available and the influence was even stronger.

DEFORMATION OF B-SPLINE BASED PLASTICINE MATERIAL MODEL IN VIRTUAL REALITY ENVIRONMENT

2017 ◽  
Vol 5 (3) ◽  
pp. 15
Author(s):  
GANDOTRA SANDEEP ◽  
Pungotra Harish ◽  
Moudgil Prince Kumar ◽  
◽  
◽  
...  
Keyword(s):  
Virtual Reality ◽  
Material Model ◽  
Virtual Reality Environment ◽  
B Spline

scholarly journals Combining tDCS With a Motor-Cognitive Task to Reduce the Negative Impact of Dual-Tasking on the Gait of Older Adults

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 287-288
Author(s):  
Jeffrey Hausdorff ◽  
Nofar Schneider ◽  
Marina Brozgol ◽  
Pablo Cornejo Thumm ◽  
Nir Giladi ◽  
...  
Keyword(s):  
Older Adults ◽  
Virtual Reality ◽  
Executive Function ◽  
Dual Task ◽  
Gait Speed ◽  
Negative Impact ◽  
Virtual Reality Environment ◽  
Dual Tasking ◽  
Concurrent Performance ◽  
Dual Task Cost

Abstract The simultaneous performance of a secondary task while walking (i.e., dual tasking) increases motor-cognitive interference and fall risk in older adults. Combining transcranial direct current stimulation (tDCS) with the concurrent performance of a task that putatively involves the same brain networks targeted by the tDCS may reduce the negative impact of dual-tasking on walking. We examined whether tDCS applied while walking reduces the dual-task costs to gait and whether this combination is better than tDCS alone or walking alone (with sham stimulation). In 25 healthy older adults (aged 75.7±10.5yrs), a double-blind, within-subject, cross-over pilot study evaluated the acute after-effects of 20 minutes of tDCS targeting the primary motor cortex and the dorsal lateral pre frontal cortex during three separate sessions:1) tDCS while walking on a treadmill in a virtual-reality environment (tDCS+walking), 2) tDCS while seated (tDCS+seated), and 3) walking in the virtual-reality environment with sham tDCS (sham+walking). The complex walking condition taxed motor and cognitive abilities. During each session, single- and dual-task walking and cognitive function were assessed before and immediately after stimulation. Compared to pre-tDCS performance, tDCS+walking reduced the dual-task cost to gait speed (p=0.004) and other gait features (e.g., variability p=0.02), and improved (p<0.001) executive function (Stroop interference score). tDCS+seated and sham+walking did not affect the dual-task cost to gait speed (p>0.17). These initial findings demonstrate that tDCS delivered during challenging walking ameliorates dual-task gait and executive function in older adults, suggesting that the concurrent performance of related tasks enhances the efficacy of the neural stimulation and mobility.

scholarly journals Revealing Hidden Local Cultural Heritage through a Serious Escape Game in Outdoor Settings

Information ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Stavroula Tzima ◽  
Georgios Styliaras ◽  
Athanasios Bassounas
Keyword(s):  
Virtual Reality ◽  
Augmented Reality ◽  
Cultural Heritage ◽  
Physical Environment ◽  
Local History ◽  
Educational Context ◽  
Virtual Reality Technology ◽  
The Real ◽  
Hybrid Type ◽  
Game Mechanics

Escape Rooms are presently considered a very popular social entertainment activity, with increasing popularity in education field, since they are considered capable of stimulating the interest of players/students and enhancing learning. The combined game mechanics have led to blended forms of Escape Rooms, the Serious Escape Games (SEGs) and the hybrid type of Escape Rooms that uses Augmented Reality (AR)/Virtual Reality technology, a type that is expected to be widely used in the future. In the current study, the MillSecret is presented, a multi-player Serious Escape Game about local cultural heritage, where the players must solve a riddle about the cultural asset of watermills. MillSecret uses AR technology and it was designed to be conducted in the real-physical environment and in an informal educational context. The paper describes the game, its implementation, the playing process, and its evaluation, which aimed to study the feasibility of game conduction in outdoor settings and the views and experience of players with the game, the local cultural heritage and local history. Evaluation results reveal, among other findings, a very positive first feedback from players that allows us to further evolve the development of the game.

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