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Our goal is to automatically generate CAD 3D models from 2D sketches as part of a design chain where models should be procedural, containing features arranged in a model tree and linked to suitable datums. Current procedural models capture much about the design intent and are easy to edit, but must be created from scratch during the detailed design state—given conceptual sketches as used by designers in the early part of the design process, current sketch-based modeling approaches only output explicit models. Thus, we describe an approach to extract high-level information directly from 2D engineering wireframe sketches and use it to complete a CSG feature tree, which serves as a model tree for a procedural 3D CAD model. Our method extracts procedural model information directly from 2D sketches in the form of a set of features, plus a set of datums and relationships between these features. We detect and analyze features of 2D sketches in isolation, and define the CSG feature tree by the parent–child relationships between features, and combine this information to obtain a complete and consistent CSG feature tree that can be transferred to a 3D modeler, which reconstructs the model. This paper focuses on how to extract the feature datums and the extrusion operation from an input 2D sketch. [Display omitted] • We create a complete CAD model tree from a vectorized sketch of a polyhedral shape • The method extracts the cross-section and auxiliary reference system of each feature • The approach works when line drawing is a connected graph or disconnected subgraphs • Output serves as proof of concept to demonstrate that it can build a procedural model [ABSTRACT FROM AUTHOR]

Humans have developed strategies of varying complexity to augment their probability of survival and success in complex environments. In contemporary outdoor adventure scenarios, advances in knowledge, training and technology have been adopted to make us safer, or make us feel safer. Avalanche-prone terrain is one such complex environment where uncertainty is key. A small-sample pilot study was conducted during a 3-year trial of mandatory avalanche transceiver, shovel and probe use at Glenmore Lodge, sportscotland National Outdoor Training Centre. The perceived effects that the equipment might have on participants' risk perceptions and risk-taking behaviour were investigated through semi-structured interviews. Patterns of avalanche risk perception and relationship with the safety equipment varied strongly between expertise levels, and a discrepancy between declared risk behaviour and action, demonstrations of optimistic bias and defensive denial were evident. Wider implications are suggested regarding subjective relationships with both risk and technology in adventure settings and, in our leisure more generally. [ABSTRACT FROM AUTHOR]

This study investigates families who choose to co-participate in outdoor adventure holidays, and explores how they benefit from these shared experiences. In so doing, it seeks to determine the role of adventure tourism in developing and enhancing family well-being (FWB). Hyper-modern family life for many is powered by technological hardware, each room in the house replete with on-line pleasures, distractions and identities. In response to this dystopia, some families opt to take adventure holidays together. However, scholarship concerning collective experiences of adventurous leisure, in this case as families, is limited. Using a qualitative whole family approach, 15 (adventure tourist) families were interviewed, totalling 62 interviewees (29 adults and 33 children under 18 years old), in their home environments. Four key themes related to FWB emerged. First, families extended their active lifestyles to adventure holidays and repeatedly mentioned the health and fitness benefits gained from these experiences. Second, adventure holidays facilitated unmediated time together for families. Third, parents harboured ideals of positive personal development for their children in these adventure settings. Fourth, making memories during adventure holidays, and recollecting these post-trip, were integral to family bonding. Further research should consider non-traditional families, and various socio-economic and cultural groups in this context. [ABSTRACT FROM AUTHOR]

Despite the prevalence of sustainability discourses across the Global North, for the majority of people abstract issues of sustainability often have a low salience with the realities of travel choices. Researchers examining sustainable tourism recognise that any changes resulting in sustainable performance are likely to come about as a result of shifts in everyday highly routinised social practices, relations and socio-technical structures. Attending to these debates, this paper examines relations between social practice, sustainability and tourism through the rise in foraging tourism in the United Kingdom. Using evidence from interviews and media analysis detailing perspectives of foraging course leaders and attendees, alongside participant observation, the paper records the ways in which foraging experiences are negotiated and accomplished in commercial contexts and what participants “do” with the ideas and practices post-experience. By engaging with debates surrounding the meanings of sustainable tourism, the paper extends understanding of these concepts through the identification of foraging tourism as a facilitator in rethinking everyday practice and discourse. The paper ends by evaluating the potentials of tourism in facilitating sustainable performance and discourse. [ABSTRACT FROM AUTHOR]

The ethnographic data considered here were gathered over a seven-month period on and around the Isle of Anglesey in North Wales. The data were partly collected during sea kayaking courses at a commercial outdoor centre and also during more informal outings with independent members of a sea kayaking club. Material recorded on accompanied journeys, during participation on group courses and on expeditions was triangulated with notes from semi-structured interviews and spontaneous discussions. The notions of marginal danger and of apparently approaching the 'edge' are key characteristics of the late-modern forms of adventurous leisure. It is proposed that, rather like the strange vertical world of the rock climber or the subterranean one of the potholer, the sea kayakers' environment is an alien, marginal, liminoid world. The ocean is not the natural territory of human beings. The kayakers move from the land to the sea and from comfort to hardship, from security to uncertainty, passivity to commitment and from action governed via ocular experience to total bodily/sensual immersion. Importantly, these shared experiences provide belonging in the ecstatic, temporary, Dionysiac communities who meet in these marginal places and situations in search of adventure and escape. Danger is but a small part of the meaning of such activity; it is the liminoid experience that is of key importance to participants. [ABSTRACT FROM AUTHOR]

Abstract: The problem of identifying the topology implied by wireframe drawings of polyhedral objects requires the identification of face loops, loops of edges which correspond to a face in the object the drawing portrays. In this paper, we survey the advantages and limitations of known approaches, and present and discuss test results which illustrate the successes and failures of a currently popular approach based on Dijkstra’s Algorithm. We conclude that the root cause of many failure cases is that the underlying algorithm assumes that the cost of traversing an edge is fixed. We propose a new polynomial-order algorithm for finding faces in wireframes. This algorithm could be adapted to any graph-theoretical least-cost circuit problem where the cost of traversing an edge is not fixed but context-dependent. [Copyright &y& Elsevier]

I comment on a paper describing a method for inflating a 2D wireframe topological representation of an object to 3D. There are several problems with this paper and the method it describes. An oversimplified problem statement and concentration on mathematical ingenuity rather than comprehension lead the authors to develop a method which is not well-suited to the problem. Failure to take proper account of previous work leads them to compare their method, not with the true state of the art, but with older, less successful approaches. Finally, they omit entirely any mention of, let alone a proposed solution to, the most intractable problem in the area, that of finding resolution sequences. [ABSTRACT FROM AUTHOR]

I comment on a paper describing a method for deducing the hidden topology of an object portrayed in a 2D natural line drawing. The principal problem with this paper is that it cannot be considered an advance on (or even an equal of) the state of the art as the approach it describes makes the same limiting assumptions as approaches proposed 10 years ago. There are also important omissions in the review of related work. [ABSTRACT FROM AUTHOR]

Adventure expeditions are characterised by their unique temporal and spatial separateness from the quotidian and their exploratory and oft times risky nature. As such they offer a multitude of possibilities in research terms for the inquisitive investigator. Few studies however have considered the researcher's experience of exploring such settings. Primarily methodological in focus, this paper examines the challenges and management of the adventure-researcher's multiple roles during a sea kayaking expedition. An expedition observation framework is constructed as a tool to aid the conceptualisation of the field. In a candid and reflexive social commentary, the relative and fluid positioning of the researcher in insider-outsider terms is probed and despite their nuanced differences, the interplay of ethnography and autoethnography in achieving this. The concept of existential authenticity as a complementary theoretical framework is used to illustrate the marginality and liminal nature of the adventure scape and the researcher's task within it. [ABSTRACT FROM AUTHOR]

Ever-changing weather and sea conditions constitute environmental hazards that sea kayakers must pay attention to and act upon to stay safe. The aim of this study was to propose a tool to aid sea kayakers’ situation awareness (SA). We developed a checklist guided by theory on the concept of SA and expert problem detection, judgement and decision-making, along with knowledge concerning previous incidents and important risk factors in sea kayaking. The checklist consists of two parts: a guide to how paddlers can improve their SA and decision-making skills, and an overview of what critical factors should be evaluated before and during a sea kayak trip. We argue that the checklist may improve risk assessment and management among sea kayakers, help to prevent distress and future incidents, and ultimately potentially save lives. Finally, we wish to stimulate debate concerning risk management in sea kayaking and outdoor education. [ABSTRACT FROM AUTHOR]

As part of a strategy for creating 3D models of engineering objects from a sketched input, we attempt to identify mirror symmetry planes early in the process. Our input is a 2D line-drawing derived from a single view sketch of a polyhedral shape, and suitable cues are used to identify mirror symmetry planes algorithmically. Previous attempts to simplify the search space use incomplete criteria. In this paper, we further simplify the search space by scoring valid symmetry planes by their likelihood, i.e., we do not assert “this is a symmetry plane” but “this is more/less likely to be a symmetry plane”. [ABSTRACT FROM AUTHOR]

Fitting elliptical arcs to strokes of an input sketch is discussed. We describe an approach which automatically combines existing algorithms to get a balance of speed and precision. For measuring precision, we introduce fast metrics which are based on perceptual criteria and are tolerant of sketching imperfections. We return a likelihood estimate based on these metrics rather than deterministic yes/no result, in order that the approach can be used in higher-level collaborative-decision recognition flows. [ABSTRACT FROM AUTHOR]