Augmented Reality (AR) holds significant potential to facilitate users in executing manual tasks. For effective support, however, we need to understand how showing movement instructions in AR affects how well people can follow those movements in real life. In this paper, we examine the degree to which users can synchronize the speed of their movements with speed cues presented through an AR environment. Specifically, we investigate the effects of timing in AR visual guidance. We assess performance using a highly realistic Mixed Reality (MR) welding simulation. Welding is a task that requires very precise timing and control over hand and arm motion. Our results show that upfront visual guidance (before manual task execution) alone often fails to transfer the knowledge of intended speeds, especially at higher target speeds. Live guidance (during manual task execution) during the activity provides more accurate speed results but typically requires a higher overshoot at the start. Optimal outcomes occur when visual guidance appears upfront and continues during the activity for users to follow through.

Cleanroom cleaning is a surface coverage task where the pattern should be followed correctly, and the entire surface should be covered. We investigate the efficacy of augmented reality (AR) by implementing various pattern guidance designs to enhance a cleanroom cleaning task. We developed an AR guidance system for cleaning procedures and evaluated four distinct pattern guidance methods: (1) breadcrumbs, (2) examples, (3) middle lines, and (4) outlines. We vary the instructions on the entire surface or as a single step. To measure performance, accuracy, and user satisfaction associated with each guidance method, we conducted a large-scale (n=864) between-subjects study. Our findings indicate that single step instructions proved to be more intuitive and efficient than full instructions, especially for the breadcrumbs. We also discussed the implications of our results for the development of AR applications for surface coverage and pattern optimization.

In many jobs, workers execute precise line tracing tasks; welding, spray painting, or chiseling, for example. Training and support for such tasks can be done using VR and AR. However, to enable workers to achieve the required precision in movement and timing, the effect of visual guidance on continuous movement needs to be explored. In VR environments, we want to ensure people are trained so that the obtained skill is transferable to a real-world context, whereas, in AR, we want to ensure an ongoing task can be completed successfully when adding visual guidance. To simulate these various contexts, we employ a VR environment to investigate the effectiveness of different visualizations for motion-based guidance in a line tracing task. We tested five different visualizations, including faster and slower arrows on the pen, the same arrows on the line, a dynamic graph on the pen or line, and a ghost object to follow. Each visualization was tested with the same set of five lines of different target speeds (2cm/s to 10 cm/s in steps of 2 cm/s) with a training line of 5 cm/s. Our results show that the example ghost on the line turns out to be the most efficient visualization for allowing users to achieve a specific speed. Users also perceived this visualization as the most engaging and easy to use. These findings have significant implications for the development of AR-based guidance systems, specifically in the realm of speed control, across diverse domains such as industrial applications, training, and entertainment.

Abstract In this paper we deal with paint‐on‐glass animation, which is a technique for making animated films by pushing slow‐drying paints from frame to frame directly under the camera. As artwork is continuously destroyed upon creating new frames, the animator is not able to rehearse or refine the animation afterwards. Furthermore, due to impracticable issues like how to stack up layers containing wet paint or how to overlay masks on the wet medium, one has to take both creative as technical decisions for each shot. Our approach consists of an interactive paint setup that physically simulates paint media. Together with a set of digital tools the artist is relieved from the difficult task of sustaining a constant frame‐to‐frame coherence while animating and is given the possibility to modify or undo earlier paint modifications. Regarding the interaction part, the artist stays in full control by employing a tangible interface. This allows artists to push pigment with their fingers, use special‐purpose digital brushes, or even to employ real life tools like paper tissue. Feedback from artists confirms the real‐life behaviour of stretching and smudging the paint as well as interacting with the setup, resulting in a natural and reality‐based methodology. Copyright © 2011 John Wiley & Sons, Ltd.

Abstract In this paper we describe the way in which emotion‐related data can efficiently be exchanged between participants in a large‐scale networked virtual environment. This type of metadata is extracted from real‐time captured video streams using off‐the‐shelf webcams and applied onto a two‐dimentional (2D) stylised avatar; thereby improving the immersion the user experiences while navigating and communicating in the virtual world. As emotion‐related data—once processed through the system—can be considered a specific type of state information, a generic networked virtual environment architecture can be used to distribute the information between participants. We have opted to extend the in‐house developed architecture for large‐scale virtual interactive communities (ALVIC‐NG) architecture to be able to process the information flows. We will show that the inclusion of this new type of information does not have a detrimental effect on the scalability of the system. Copyright © 2009 John Wiley & Sons, Ltd.

Abstract In this paper we argue for the concept of brushes and pigments enhanced with behavioural intelligence as a complement to established 2D computer animation techniques. Our approach allows the user to enrich and animate interactively created images by semi‐autonomously embedding procedural animation into them. This way, artistic skills of trained animators become within reach of everyone in the digital world, even to completely novice users. To exemplify this concept, we elaborate on several special‐purpose brushes and animated pigment for painting with animation. These include a programmable semi‐autonomous brush used to paint variations of strokes in successive frames (e.g. flames of fire), the moving‐dab brush which enables dabs of paint to follow a user‐defined path (e.g. smoke puffs) and animated pigment to produce secondary motion such as vibrant or waving paint textures. We believe our system offers a new fresh perspective on 2D computer aided animation production and associated tools. Copyright © 2008 John Wiley & Sons, Ltd.

We present a novel approach to design artistic and believable trees in a cartoon-like style, which can be rendered by an animated camera to produce a convincing 3D-like experience. While computer assisted traditional animation is able to generate the desired effects, this approach still depends too much on the creation of many hand drawn images. Existing approaches fully depending on 3D geometries, on the other hand, give little artistic freedom and have difficulties to avoid artifacts popping up in successive frames. In order to provide good solutions to these difficulties, we present a hybrid (2.5D) framework, combining the advantages of both 2D and 3D approaches. From an underlying 3D geometry we get the necessary information to obtain an acceptable level of 3D behavior and a good frame-to-frame coherence. In the same framework, 2D artistic input is employed to obtain any desired 'look', both of the rendering and of the animation.

Although computer assistance for traditional animation is gaining a lot of attention during recent years, it still has to cope with many limitations. Part of the current research focuses on employing full 3D input models, which are rendered and even animated in many different non-photorealistic (NPR) styles. Disadvantages are the need to create complicated 3D models and the many difficulties to achieve lively movements. Purely 2D approaches, on the other hand, need many elaborated single drawings. Getting perspective right and retaining volumes are a major problem in that approach to computer assisted traditional animation, due to the complete lack of 3D information. Unfortunately, the employed software is ignorant about the approximate 3D representation in the animator's mind. In this paper, we present a novel tool for traditional animation, based on an approximate 3D model. This tool helps retaining volumes and proportions, and ensures frame-to-frame coherence.

This paper introduces a new method for automatic in-betweening in computer assisted traditional animation. The solution is based on novel 2.5D modelling and animation techniques within the context of a multi-level approach, starting with basic 2D drawing primitives (curves) at level 0, over explicit 2.5D modelling structures at level 1 and inclusion of 3D information by means of skeletons at level 2, to high-level deformation tools (and possibly other tools for supporting specific purposes such as facial expression) at level 3. The underlying methodologies are explained and implementation results are elucidated.