92 research outputs found
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View-dependent adaptive cloth simulation
This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method adjusts the criteria controlling refinement to account for visibility and apparent size in the camera's view. Objectionable dynamic artifacts are avoided by anticipative refinement and smoothed coarsening. This approach preserves the appearance of detailed cloth throughout the animation while avoiding the wasted effort of simulating details that would not be discernible to the viewer. The computational savings realized by this method increase as scene complexity grows, producing a 2ร speed-up for a single character and more than 4ร for a small group
Transforming Dress
In this paper, we produce a fashion show in which a dress is transformed over time, with a storyline of a robot that experiences some emotional changes after falling in love, sheds a symbolic teardrop and at the end becomes a lovely woman. This transformability, which cannot be done in a real fashion show, could open the potential for a new kind of creativity in the fashion industry
Parallelized Incomplete Poisson Preconditioner in Cloth Simulation
Efficient cloth simulation is an important problem for interactive applications that involve virtual humans, such as computer games. A common aspect of many methods that have been developed to simulate cloth is a linear system of equations, which is commonly solved using conjugate gradient or multi-grid approaches. In this paper, we introduce to the computer gaming community a recently proposed preconditioner, the incomplete Poisson preconditioner, for conjugate gradient solvers. We show that the parallelized incomplete Poisson preconditioner (PIPP) performs as well as the current state-of-the-art preconditioners, while being much more amenable to standard thread-level parallelism. We demonstrate our results on an 8-core Apple* Mac* Pro and a 32-core code name Emerald Ridge system
Efficient Clothing Fitting from Data.
A major drawback of shopping for clothes on-line is that the customer cannot try on clothes and see if they fit or
suit them. One solution is to display clothing on an avatar, a 3D graphical model of the customer. However the
normal technique for modeling clothing in computer graphics, cloth dynamics, suffers from being too processor
intensive and is not practical for real time applications. Hence, retailers normally rely on a fixed set of body
models to which clothes are pre-fitted. As the customer has to choose from this limited set the fit is typicallly not
very representative of how the real clothes will fit. We propose a method that uses a compromise between these
two methods. We generate a set of example avatars by performing Principal Component Analysis on a dataset of
avatars. Clothes are pre-fitted to these examples off-line. Instead of asking the customer to choose from the set of
examples we are able to represent the users avatar as a weighted sum of the examples, we then fit clothes as the
same weighted sum over the clothes fitted to the examples
Recommended from our members
Fast Image-Based Model of Mitral Valve Closure for Surgical Planning
Surgical repair of the mitral valve results in better
outcomes than valve replacement, yet diseased valves
are often replaced due to the technical difficulty of the
repair process. A surgical planning system based on
patient-specific medical images that allows surgeons to
simulate and compare potential repair strategies could
greatly improve surgical outcomes. The system must
simulate valve closure quickly and handle the complex
boundary conditions imposed by the chords that tether
the valve leaflets. We have developed a process for
generating a triangulated mesh of the valve surface
from volumetric image data of the opened valve. The
closed position of the mesh is then computed using a
mass-spring model of dynamics. In the mass-spring
model, triangle sides are treated as linear springs
supporting only tension. Chords are also treated as
linear springs, and self-collisions are detected and
handled inelastically. The equations of motion are
solved using implicit numerical integration. The
simulated closed state is compared with an image of the
same valve taken in the closed state to assess accuracy
of the model. The model exhibits rapid valve closure
and is able to predict the closed state of the valve with
reasonable accuracy.Engineering and Applied Science
๋์นญ์ ์ธ ์์์ ์๋ฎฌ๋ ์ด์ ๊ฐ์์ ์ํ ํจํด ๋ฏธ๋ฌ๋ง ์๊ณ ๋ฆฌ์ฆ
ํ์๋
ผ๋ฌธ (์์ฌ)-- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ ๋ณด๊ณตํ๋ถ, 2019. 2. ๊ณ ํ์.๋ณธ ๋
ผ๋ฌธ์ ์์-๋ฐ๋ ์๋ฎฌ๋ ์ด์
์ ์๋ ํฅ์์ ์ํ ํจํด๋ฏธ๋ฌ๋ง ๋ฐฉ๋ฒ์ ์ ์ํ๋ค. ์ด ๋ฐฉ๋ฒ์ ๋ชธ ๋งค์ฌ์ ์ท์ ํจ๋์ด ์์นํ Y-Zํ๋ฉด์ ๋ํด ๋์นญ์ผ ๊ฒฝ์ฐ์ ์ฌ์ฉ๊ฐ๋ฅํ๋ค. ๋ณดํต์ ๋จ์ฑ๋ณต์ด๋ ๊ธฐ์ฑ๋ณต๊ณผ ๊ฐ์ ์ท์ด ์ข์ฐ๊ฐ ๋์นญ์ธ ๊ฒฝ์ฐ๊ฐ ๋ง๋ค.
๊ธฐ์กด ์๋ฎฌ๋ ์ด์
์์๋ ๋ชจ๋ ์ท์ ์ ์ ๋ค์ ๋ํด conjugate gradient ๋ฐฉ๋ฒ์ ์ด์ฉํด ์์คํ
ํ๋ ฌ์ ํ์๋ค. ๋ฌธ์ ๋ conjugate gradient ๋ฐฉ๋ฒ์ ์ ์ ์์ ๋ํด ์ง์์ ์ธ ์๊ฐ ๋ณต์ก๋๋ฅผ ๊ฐ์ง๋ฏ๋ก, ๊ณ ํด์๋๋ฅผ ์ํด ์ ์ ์ ์๊ฐ ์ฆ๊ฐํ ์๋ก ์๋ฎฌ๋ ์ด์
์๊ฐ์ด ์ง์์ ์ผ๋ก ์ฆ๊ฐํ๋ค๋ ๊ฒ์ด๋ค. Pattern Mirroring ๋ฐฉ๋ฒ์ ์ด์ฉํ๋ฉด ๊ณ์ฐํด์ผํ๋ ์์คํ
๋ฐฉ์ ์์ ์์ด ๋ฐ์ ๋ก ์ค์ด๋ค๊ธฐ ๋๋ฌธ์, ์๋ฎฌ๋ ์ด์
์ ํ์ํ ์๊ฐ๋ ์ค์ด๋ค๊ฑฐ๋ผ๊ณ ๊ธฐ๋ํ ์ ์๋ค. ๊ฒฐ๊ณผ์ ์ผ๋ก ํจํด๋ฏธ๋ฌ๋ง ์๊ณ ๋ฆฌ์ฆ์ ์ด์ฉํ๋ฉด 1.4๋ฐฐ (37%)์ ์๋ ํฅ์์ ๋ณด์๋ค.
1์ฅ ๋์
์์๋ ์ท์ ์๋ฎฌ๋ ์ด์
ํ๋ ๊ณผ์ ์ธ ์์คํ
๋ฐฉ์ ์์ ํธ๋ ๋ฐฉ๋ฒ, ์ถฉ๋์ฒ๋ฆฌ๋ฅผ ํ๋ ๋ฐฉ๋ฒ์ ๋ํด ์ค๋ช
ํ๋ค. iterative method์ธ conjugate gradient๊ฐ ์ท์ ์ ์ ๋ค์ ์๋๋ฅผ ๊ฒฐ์ ํ๊ธฐ ์ํด ์ฌ์ฉ๋์๋ค. 2์ฅ ๊ด๋ จ ์ฐ๊ตฌ์์๋ ์๋ฎฌ๋ ์ด์
๊ฐ์ํ๋ฅผ ์ํ ์ฐ๊ตฌ๋ฅผ ์๊ฐํ๋ค. 3์ฅ์์ pattern mirroring ์๊ณ ๋ฆฌ์ฆ์ ์๊ฐํ๋ค. 4์ฅ์์๋ ํจํด ๋ฏธ๋ฌ๋ง ๋ฐฉ๋ฒ์ ์ฌ์ฉํ๋ค๋ฉด ๋ฐ์ํ ์ ์๋ ๋ฌธ์ ๊ฐ ๋ช๊ฐ์ง ์๋๋ฐ, ์ด ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ๋ ๋ฐฉ๋ฒ์ ๋ํด ์ค๋ช
ํ๋ค. 5์ฅ์์๋ ํจํด ๋ฏธ๋ฌ๋ง ๋ฐฉ๋ฒ์ ๊ธฐ์กด์ ์๋ฎฌ๋ ์ด์
๋ฐฉ๋ฒ๊ณผ ๋น๊ตํด์ ์๋ ํฅ์์ ๋ํ๋ก ์ ์ํ๊ณ , ๊ฒฐ๊ณผ ์ด๋ฏธ์ง๋ฅผ ๋น๊ตํ๋ค.This paper describes the Pattern mirroring algorithm to reduce simulation time for cloth body simulation. This method is applicable for symmetric panel and symmetric body meshes centered on YZ plane: typically, man's suit and ready-make cloth is target of this method.
As the ordinal simulation method, apply conjugate gradient method to every vertices on cloth mesh in order to solve system matrix. The problem is that the time for simulation is getting longer as the number of cloth vertices increases for high resolution. This is because the time complexity of conjugate gradient is exponential. Using pattern mirroring method, size of system matrix equation is half comparing ordinal method. So I can expect that the time for simulation reduces. The proposed method reduces simulation time up to 1.4 times (37%), by halving the matrix size of the linear equation.
At chapter 1 introduction, describe the process of simulation, method of solving system equation and collision handling. An iterative method 'conjugate gradient method' is used to determine velocity of vertices of clothes.
At chapter 2 relative work, explain about previous acceleration research for cloth simulation. At chapter 3, explain Pattern mirroring algorithm. But some problems could occur when using this method. At chapter 4, suggest solutions to handle these artifact as post-process step. At chapter 5, represent table to comparing the average time to simulate cloth in ordinal method and pattern mirroring method. Also represent image to difference of two result. Finally at chapter 6, describe conclusion and limitation of Pattern mirroring algorithm.Abstract
Contents
List of Figures
List of Tables
1 Introduction
1.1 Time integration method
1.2 System matrix
1.3 Conjugate gradient method
1.4 Collision handling method
1.5 Overview of Pattern mirroring algorithm
2 Previous Work
3 Pattern Mirroring Method
3.1 1st step: Set Constraint Plane and Halving Mesh
3.2 2nd step: Simulation for Half Pane
3.3 3rd step: Mirroring Half Mesh
4 Artifacts Handling
4.1 Project crossed vertices at halving step
4.2 Penetration between original and mirrored mesh
5 Experiment Result
5.1 T-shirt
5.2 Jacket
6 Conclusion
Bibliography
์ด๋ก
๊ฐ์ฌ์๊ธMaste
Fast Simulation of Mass-Spring Systems
We describe a scheme for time integration of mass-spring systems that makes use of a solver based on block coordinate descent. This scheme provides a fast solution for classical linear (Hookean) springs. We express the widely used implicit Euler method as an energy minimization problem and introduce spring directions as auxiliary unknown variables. The system is globally linear in the node positions, and the non-linear terms involving the directions are strictly local. Because the global linear system does not depend on run-time state, the matrix can be pre-factored, allowing for very fast iterations. Our method converges to the same final result as would be obtained by solving the standard form of implicit Euler using Newtonโs method. Although the asymptotic convergence of Newtonโs method is faster than ours, the initial ratio of work to error reduction with our method is much faster than Newtonโs. For real-time visual applications, where speed and stability are more important than precision, we obtain visually acceptable results at a total cost per timestep that is only a fraction of that required for a single Newton iteration. When higher accuracy is required, our algorithm can be used to compute a good starting point for subsequent Newtonโs iteration
Automatic modeling of virtual humans and body clothing
Highly realistic virtual human models are rapidly becoming commonplace in computer graphics. These models, often represented by complex shape and requiring labor-intensive process, challenge the problem of automatic modeling. The problem and solutions to automatic modeling of animatable virtual humans are studied. Methods for capturing the shape of real people, parameterization techniques for modeling static shape (the variety of human body shapes) and dynamic shape (how the body shape changes as it moves) of virtual humans are classified, summarized and compared. Finally, methods for clothed virtual humans are reviewe
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