4,503 research outputs found
Sketching-out virtual humans: A smart interface for human modelling and animation
In this paper, we present a fast and intuitive interface for sketching out
3D virtual humans and animation. The user draws stick figure key frames first and
chooses one for âfleshing-outâ with freehand body contours. The system
automatically constructs a plausible 3D skin surface from the rendered figure, and
maps it onto the posed stick figures to produce the 3D character animation. A
âcreative model-based methodâ is developed, which performs a human perception
process to generate 3D human bodies of various body sizes, shapes and fat
distributions. In this approach, an anatomical 3D generic model has been created with
three distinct layers: skeleton, fat tissue, and skin. It can be transformed sequentially
through rigid morphing, fatness morphing, and surface fitting to match the original
2D sketch. An auto-beautification function is also offered to regularise the 3D
asymmetrical bodies from usersâ imperfect figure sketches. Our current system
delivers character animation in various forms, including articulated figure animation,
3D mesh model animation, 2D contour figure animation, and even 2D NPR animation
with personalised drawing styles. The system has been formally tested by various
users on Tablet PC. After minimal training, even a beginner can create vivid virtual
humans and animate them within minutes
Posing 3D Models from Drawing
Inferring the 3D pose of a character from a drawing is a complex and under-constrained problem. Solving it may help automate various parts of an animation production pipeline such as pre-visualisation. In this paper, a novel way of inferring the 3D pose from a monocular 2D sketch is proposed. The proposed method does not make any external assumptions about the model, allowing it to be used on different types of characters. The inference of the 3D pose is formulated as an optimisation problem and a parallel variation of the Particle Swarm Optimisation algorithm called PARAC-LOAPSO is utilised for searching the minimum. Testing in isolation as well as part of a larger scene, the presented method is evaluated by posing a lamp, a horse and a human character. The results show that this method is robust, highly scalable and is able to be extended to various types of models
Robust Blockwise Random Pivoting: Fast and Accurate Adaptive Interpolative Decomposition
The interpolative decomposition (ID) aims to construct a low-rank
approximation formed by a basis consisting of row/column skeletons in the
original matrix and a corresponding interpolation matrix. This work explores
fast and accurate ID algorithms from five essential perspectives for empirical
performance: (a) skeleton complexity that measures the minimum possible ID rank
for a given low-rank approximation error, (b) asymptotic complexity in FLOPs,
(c) parallelizability of the computational bottleneck as matrix-matrix
multiplications, (d) error-revealing property that enables automatic rank
detection for given error tolerances without prior knowledge of target ranks,
(e) ID-revealing property that ensures efficient construction of the optimal
interpolation matrix after selecting the skeletons. While a broad spectrum of
algorithms have been developed to optimize parts of the aforementioned
perspectives, practical ID algorithms proficient in all perspectives remain
absent. To fill in the gap, we introduce robust blockwise random pivoting
(RBRP) that is parallelizable, error-revealing, and exact-ID-revealing, with
comparable skeleton and asymptotic complexities to the best existing ID
algorithms in practice. Through extensive numerical experiments on various
synthetic and natural datasets, we empirically demonstrate the appealing
performance of RBRP from the five perspectives above, as well as the robustness
of RBRP to adversarial inputs
Making masks for Maui: Keeping the macro task in mind
New Zealand primary school children in technology lessons often design and create an artifact in response to a scenario that relates to their interests and experiences. Usually the task is undertaken over several days. In this paper we draw on data generated within the INSiTE study, a three-year study exploring the nature of effective student-teacher interactions around science and technology ideas. The teacher in this paper planned for her children to create a mask for their forthcoming school production: 'How Maui found the secret of fire'. As the children worked on the macro task, that of designing and making a mask, meso and micro tasks emerged. The teacher assisted the children to identity and resolve these, hearing in mind that the ultimate aim was their successful participation in the school production. When teachers assist children to maintain a focus on the overall or macro task goals their artifact fulfils the specifications of the scenario and children's technology understandings and skills are fostered
Matisse : Painting 2D regions for Modeling Free-Form Shapes
International audienceThis paper presents "Matisse", an interactive modeling system aimed at providing the public with a very easy way to design free-form 3D shapes. The user progressively creates a model by painting 2D regions of arbitrary topology while freely changing the view-point and zoom factor. Each region is converted into a 3D shape, using a variant of implicit modeling that fits convolution surfaces to regions with no need of any optimization step. We use intuitive, automatic ways of inferring the thickness and position in depth of each implicit primitive, enabling the user to concentrate only on shape design. When he or she paints partly on top of an existing primitive, the shapes are blended in a local region around the intersection, avoiding some of the well known unwanted blending artifacts of implicit surfaces. The locality of the blend depends on the size of smallest feature, enabling the user to enhance large, smooth primitives with smaller details without blurring the latter away. As the results show, our system enables any unprepared user to create 3D geometry in a very intuitive way
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