21,265 research outputs found
Information hiding through variance of the parametric orientation underlying a B-rep face
Watermarking technologies have been proposed for many different,types of digital media. However, to this date, no viable watermarking techniques have yet emerged for the high value B-rep (i.e. Boundary Representation) models used in 3D mechanical CAD systems. In this paper, the authors propose a new approach (PO-Watermarking) that subtly changes a model's geometric representation to incorporate a 'transparent' signature. This scheme enables software applications to create fragile, or robust watermarks without changing the size of the file, or shape of the CAD model. Also discussed is the amount of information the proposed method could transparently embed into a B-rep model. The results presented demonstrate the embedding and retrieval of text strings and investigate the robustness of the approach after a variety of transformation and modifications have been carried out on the data
Metamorphic Domain-Specific Languages: A Journey Into the Shapes of a Language
External or internal domain-specific languages (DSLs) or (fluent) APIs?
Whoever you are -- a developer or a user of a DSL -- you usually have to choose
your side; you should not! What about metamorphic DSLs that change their shape
according to your needs? We report on our 4-years journey of providing the
"right" support (in the domain of feature modeling), leading us to develop an
external DSL, different shapes of an internal API, and maintain all these
languages. A key insight is that there is no one-size-fits-all solution or no
clear superiority of a solution compared to another. On the contrary, we found
that it does make sense to continue the maintenance of an external and internal
DSL. The vision that we foresee for the future of software languages is their
ability to be self-adaptable to the most appropriate shape (including the
corresponding integrated development environment) according to a particular
usage or task. We call metamorphic DSL such a language, able to change from one
shape to another shape
Programmatic and Direct Manipulation, Together at Last
Direct manipulation interfaces and programmatic systems have distinct and
complementary strengths. The former provide intuitive, immediate visual
feedback and enable rapid prototyping, whereas the latter enable complex,
reusable abstractions. Unfortunately, existing systems typically force users
into just one of these two interaction modes.
We present a system called Sketch-n-Sketch that integrates programmatic and
direct manipulation for the particular domain of Scalable Vector Graphics
(SVG). In Sketch-n-Sketch, the user writes a program to generate an output SVG
canvas. Then the user may directly manipulate the canvas while the system
immediately infers a program update in order to match the changes to the
output, a workflow we call live synchronization. To achieve this, we propose
(i) a technique called trace-based program synthesis that takes program
execution history into account in order to constrain the search space and (ii)
heuristics for dealing with ambiguities. Based on our experience with examples
spanning 2,000 lines of code and from the results of a preliminary user study,
we believe that Sketch-n-Sketch provides a novel workflow that can augment
traditional programming systems. Our approach may serve as the basis for live
synchronization in other application domains, as well as a starting point for
yet more ambitious ways of combining programmatic and direct manipulation.Comment: PLDI 2016 Paper + Supplementary Appendice
Supporting Focus and Context Awareness in 3D Modelling Tasks Using Multi-Layered Displays
Most 3D modelling software have been developed for conventional 2D displays, and as such, lack support for true depth perception. This contributes to making polygonal 3D modelling tasks challenging, particularly when models are complex and consist of a large number of overlapping components (e.g. vertices, edges) and objects (i.e. parts). Research has shown that users of 3D modelling software often encounter a range of difficulties, which collectively can be defined as focus and context awareness problems. These include maintaining position and orientation awarenesses, as well as recognizing distance between individual components and objects in 3D spaces. In this paper, we present five visualization and interaction techniques we have developed for multi-layered displays, to better support focus and context awareness in 3D modelling tasks. The results of a user study we conducted shows that three of these five techniques improve users' 3D modelling task performance
Augmenting the field experience: a student-led comparison of techniques and technologies
In this study we report on our experiences of creating and running a student fieldtrip exercise which allowed students to compare a range of approaches to the design of technologies for augmenting landscape scenes. The main study site is around Keswick in the English Lake District, Cumbria, UK, an attractive upland environment popular with tourists and walkers. The aim of the exercise for the students was to assess the effectiveness of various forms of geographic information in augmenting real landscape scenes, as mediated through a range of techniques and technologies. These techniques were: computer-generated acetate overlays showing annotated wireframe views from certain key points; a custom-designed application running on a PDA; a mediascape running on the mScape software on a GPS-enabled mobile phone; Google Earth on a tablet PC; and a head-mounted in-field Virtual Reality system. Each group of students had all five techniques available to them, and were tasked with comparing them in the context of creating a visitor guide to the area centred on the field centre. Here we summarise their findings and reflect upon some of the broader research questions emerging from the project
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