Browsing by Author "Fernando, Terrence"

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    A Constraint Manager to Support Virtual Maintainability
    (The Eurographics Association, 2022) Marcelino, Luis; Murray, Norman; Fernando, Terrence; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Virtual prototyping tools have already captivated the industry's interest as a viable design tool. One of the key challenges for the research community is to extend the capabilities of Virtual Reality technology beyond its current scope of ergonomics and design reviews. The research presented in this paper is part of a larger research programme that aims to perform maintainability assessment on virtual prototypes. This paper discusses the design and implementation of a geometric constraint manager that has been designed to support physical realism and interactive assembly and disassembly tasks within virtual environments. The key techniques employed by the constraint manager are direct interaction, automatic constraint recognition, constraint satisfaction and constrained motion. Various optimisation techniques have been implemented to achieve real-time interaction with large industrial models.
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    Interactive Assembly Modelling within a CAVE Environment
    (The Eurographics Association, 2023) Fernando, Terrence; Marcelino, Luis; Wimalaratne, Prasad; Tan, Kevin; Beatriz Sousa Santos; Joaquim A. Jorge; José Manuel Dionísio
    This paper presents the design and implementation of a constraint-based virtual environment for supponing interactive assembly and maintenance tasks within an immersive virtual reality environment. The system architecture of the constraint-based virtual environment is based on the integration of components such as OpenGL Optimizer, Parasolid geometric kemel, a Constraint Engine and an Assembly Relationship Graph ( ARG ). The approach presented in this paper is based on pure geometric constraints. Techniques such as automatic constraint recognition, constraint satisfaction, constraint management and constrained motion are employed to suppon interactive assembly operations and realistic behaviour of assembly pans. The rendering and the interaction capabilities of the OpenGL Optimizer graphical API has been extended to run on a CAVE environment. lnteractive assembly and disassembly operations are performed through a glove-based interface. The current system has been evaluated using two industrial case studies: digger mechanism and a helicopter rotor biade mechanism. This work is being carried out as a part of a research programme referred to as IPSEAM (/nteractive Product Simulation Environment for Assessing Assembly and Maintenance), at the Universiry of Salford.
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    Surface Collision Detection for Maintenance Support in Virtual Environments
    (The Eurographics Association, 2022) Marcelino, Luis; Figueiredo, Mauro; Fernando, Terrence; Xavier Pueyo; Manuel Próspero dos Santos; Luiz Velho
    Detecting collision between surfaces is an important feature for supporting interactive assembly operations based on the geometric constraint-based simulation. CAD models define the geometry of components using surfaces as the basic primitive while current collision detection toolkits, disregard this information and use only polygons. The automatic recognition of geometric constraints can use colliding surfaces to simulate realistic behaviour interactively. This paper presents our research into supporting surface based collision detection for use in immersive Virtual Environments. That resulted in the implementation of a surface collision detection module built on top of RAPID.