56,492 research outputs found
Sketch-based virtual human modelling and animation
Animated virtual humans created by skilled artists play a remarkable role in todayâs public entertainment. However, ordinary users are still treated as audiences due to the lack of appropriate expertise, equipment, and computer skills. We developed a new method and a novel sketching interface, which enable anyone who can draw to âsketch-outâ 3D virtual humans and animation.
We devised a âStick FigureFleshing-outSkin Mappingâ graphical pipeline, which decomposes the complexity of figure drawing and considerably boosts the modelling and animation efficiency. We developed a gesture-based method for 3D pose reconstruction from 2D stick figure drawings. We investigated a âCreative Model-based Methodâ, which performs a human perception process to transfer usersâ 2D freehand sketches into 3D human bodies of various body sizes, shapes and fat distributions. Our current system supports character animation in various forms including articulated figure animation, 3D mesh model animation, and 2D contour/NPR animation with personalised drawing styles. Moreover, this interface also supports sketch-based crowd animation and 2D storyboarding of 3D multiple character interactions. A preliminary user study was conducted to support the overall system design. Our 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
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
Sketching-out virtual humans: From 2d storyboarding to immediate 3d character animation
Virtual beings are playing a remarkable role in todayâs 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 âstick figurefleshing-outskin mappingâ 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 âcreative model-based methodâ 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
y-scaling in Quasielastic Electron Scattering from Nuclei
A relativistic single particle model is used to calculate the inclusive
reaction from 12, 40, 56, 197, and 208 nuclei in the quasielastic
region. We have shown that this model provides a very good description of the
available experimental cross sections when they are dominated by the
quasielastic process. In this paper we use this model to investigate the
dependence of -scaling on electron kinematics, particularly the electron
scattering angle, for a range of squared four momentum transfer
(GeV/c). In this kinematic domain, Coulomb distortion of the electron does
not significantly affect scaling, but final state interactions of the knocked
out nucleon do affect scaling particularly when the nucleons have lower
energies. In general, we find that scaling works for this reaction, but at
lower values of the four momentum transfer, the scaling function does have some
dependence on the electron scattering angle. We also consider a modification of
y-scaling to include small binding energy effects as a function of Z and A and
show that there is some improvement in scaling.Comment: 21 pages, 11 figure
On the complexion of pseudoscalar mesons
A strongly momentum-dependent dressed-quark mass function is basic to QCD. It
is central to the appearance of a constituent-quark mass-scale and an
existential prerequisite for Goldstone modes. Dyson-Schwinger equation (DSEs)
studies have long emphasised this importance, and have proved that QCD's
Goldstone modes are the only pseudoscalar mesons to possess a nonzero leptonic
decay constant in the chiral limit when chiral symmetry is dynamically broken,
while the decay constants of their radial excitations vanish. Such features are
readily illustrated using a rainbow-ladder truncation of the DSEs. In this
connection we find (in GeV): f_{eta_c(1S)}= 0.233, m_{eta_c(2S)}=3.42; and
support for interpreting eta(1295), eta(1470) as the first radial excitations
of eta(548), eta'(958), respectively, and K(1460) as the first radial
excitation of the kaon. Moreover, such radial excitations have electromagnetic
diameters greater than 2fm. This exceeds the spatial length of lattices used
typically in contemporary lattice-QCD.Comment: 7 pages, 2 figures. Contribution to the proceedings of the "10th
International Symposium on Meson-Nucleon Physics and the Structure of the
Nucleon (MENU04)," IHEP, Beijing, China, 30/Aug.-4/Sept./0
Exchange rate determination in Jamaica: A market microstructures and macroeconomic fundamentals approach
This paper uses hybrid models that combine economic fundamentals and micro-market variables to investigate the behaviour of US/Jamaica exchange rate. The co-integration analysis applied to post 2000 monthly data indicates, in contrast to previous studies done on Jamaica that these models give a better fit, produce parameter estimates with sensible signs and sizes and allow for long run relationships which are not present when the micro-based variables are excluded.Exchange Rates, Microstructure, Co-integration
Variable Linear Polarization from Sagittarius A*: Evidence for a Hot Turbulent Accretion Flow
We report the discovery of variability in the linear polarization from the
Galactic Center black hole source, Sagittarius A*. New polarimetry obtained
with the Berkeley-Illinois-Maryland Association array at a wavelength of 1.3 mm
shows a position angle that differs by 28 +/- 5 degrees from observations 6
months prior and then remains stable for 15 months. This difference may be due
to a change in the source emission region on a scale of 10 Schwarzschild radii
or due to a change of 3 x 10^5 rad m^-2 in the rotation measure. We consider a
change in the source physics unlikely, however, since we see no corresponding
change in the total intensity or polarized intensity fraction. On the other
hand, turbulence in the accretion region at a radius ~ 10 to 1000 R_s could
readily account for the magnitude and time scale of the position angle change.Comment: accepted for publication in ApJ
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