2,042 research outputs found
N-way morphing for 2D Animation
International audienceWe present a novel approach to the creation of varied animations from a small set of simple 2D input shapes. Instead of providing a new 2D shape for each keyframe of an animation sequence, we instead interpolate between a few example shapes in a reduced pose-space. Similar approaches have been presented in the past, but were restricted in the types of input or range of deformations allowed. In order to address these limitations, we reformulate the problem as an N-way morphing process on 2D input bitmap or vector graphics. Our formulation includes an N-way mapping technique, an efficient, rigidity preserving non-linear blending function, improved extrapolation, and a novel scattered data interpolation technique to manage the reduced pose-space. The resulting animations are correlated to paths in the reduced pose-space, allowing users to intuitively and interactively control temporal behaviors with simple gestures. We demonstrate our techniques in several example animations
Assessment criteria for 2D shape transformations in animation
The assessment of 2D shape transformations (or morphing) for animation is a difficult task because it is a multi-dimensional problem. Existing morphing techniques pay most attention to shape information interactive control and mathematical simplicity. This paper shows that it is not enough to use shape information alone, and we should consider other factors such as structure, dynamics, timing, etc. The paper also shows that an overall objective assessment of morphing is impossible because factors such as timing are related to subjective judgement, yet local objective assessment criteria, e.g. based on shape, are available. We propose using “area preservation” as the shape criterion for the 2D case as an acceptable approximation to “volume preservation” in reality, and use it to establish cases in which a number of existing techniques give clearly incorrect results. The possibility of deriving objective assessment criteria for dynamics simulations and timing under certain conditions is discussed
Using image morphing for memory-efficient impostor rendering on GPU
Real-time rendering of large animated crowds consisting thousands of virtual humans is important for several applications including simulations, games and interactive walkthroughs; but cannot be performed using complex polygonal models at interactive frame rates. For that reason, several methods using large numbers of pre-computed image-based representations, which are called as impostors, have been proposed. These methods take the advantage of existing programmable graphics hardware to compensate the computational expense while maintaining the visual fidelity. Making the number of different virtual humans, which can be rendered in real-time, not restricted anymore by the required computational power but by the texture memory consumed for the variety and discretization of their animations. In this work, we proposed an alternative method that reduces the memory consumption by generating compelling intermediate textures using image-morphing techniques. In order to demonstrate the preserved perceptual quality of animations, where half of the key-frames were rendered using the proposed methodology, we have implemented the system using the graphical processing unit and obtained promising results at interactive frame rates
Sketching-out virtual humans: From 2d storyboarding to immediate 3d character animation
Virtual beings are playing a remarkable role in today’s public entertainment, while ordinary users are still treated as audiences due to the lack of appropriate expertise, equipment, and computer skills. In this paper, we present a fast and intuitive storyboarding interface, which enables users to sketch-out 3D virtual humans, 2D/3D animations, and character intercommunication. We devised an intuitive “stick figurefleshing-outskin mapping” graphical animation pipeline, which realises the whole process of key framing, 3D pose reconstruction, virtual human modelling, motion path/timing control, and the final animation synthesis by almost pure 2D sketching. A “creative model-based method” is developed, which emulates a human perception process, to generate the 3D human bodies of variational sizes, shapes, and fat distributions. Meanwhile, our current system also supports the sketch-based crowd animation and the storyboarding of the 3D multiple character intercommunication. This 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
Morphing a Stereogram into Hologram
This paper develops a simple and fast method to reconstruct reality from
stereoscopic images. We bring together ideas from robust optical flow
techniques, morphing deformations and lightfield 3D rendering in order to
create unsupervised multiview images of a scene. The reconstruction algorithm
provides a good visualization of the virtual 3D imagery behind stereograms upon
display on a headset-free Looking Glass 3D monitor. We discuss the possibility
of applying the method for live 3D streaming optimized via an associated lookup
table.Comment: PDF, 8 pages, 4 Fig
Visualizing 2D Flows with Animated Arrow Plots
Flow fields are often represented by a set of static arrows to illustrate
scientific vulgarization, documentary film, meteorology, etc. This simple
schematic representation lets an observer intuitively interpret the main
properties of a flow: its orientation and velocity magnitude. We propose to
generate dynamic versions of such representations for 2D unsteady flow fields.
Our algorithm smoothly animates arrows along the flow while controlling their
density in the domain over time. Several strategies have been combined to lower
the unavoidable popping artifacts arising when arrows appear and disappear and
to achieve visually pleasing animations. Disturbing arrow rotations in low
velocity regions are also handled by continuously morphing arrow glyphs to
semi-transparent discs. To substantiate our method, we provide results for
synthetic and real velocity field datasets
Tetrisation of triangular meshes and its application in shape blending
The As-Rigid-As-Possible (ARAP) shape deformation framework is a versatile
technique for morphing, surface modelling, and mesh editing. We discuss an
improvement of the ARAP framework in a few aspects: 1. Given a triangular mesh
in 3D space, we introduce a method to associate a tetrahedral structure, which
encodes the geometry of the original mesh. 2. We use a Lie algebra based method
to interpolate local transformation, which provides better handling of rotation
with large angle. 3. We propose a new error function to compile local
transformations into a global piecewise linear map, which is rotation invariant
and easy to minimise. We implemented a shape blender based on our algorithm and
its MIT licensed source code is available online
Techniques for augmenting the visualisation of dynamic raster surfaces
Despite their aesthetic appeal and condensed nature, dynamic raster surface representations such as a temporal series of a landform and an attribute series of a socio-economic attribute of an area, are often criticised for the lack of an effective information delivery and interactivity.In this work, we readdress some of the earlier raised reasons for these limitations -information-laden quality of surface datasets, lack of spatial and temporal continuity in the original data, and a limited scope for a real-time interactivity. We demonstrate with examples that the use of four techniques namely the re-expression of the surfaces as a framework of morphometric features, spatial generalisation, morphing, graphic lag and brushing can augment the visualisation of dynamic raster surfaces in temporal and attribute series
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