284 research outputs found
Real-time simulation and visualisation of cloth using edge-based adaptive meshes
Real-time rendering and the animation of realistic virtual environments and characters
has progressed at a great pace, following advances in computer graphics hardware
in the last decade. The role of cloth simulation is becoming ever more important in
the quest to improve the realism of virtual environments.
The real-time simulation of cloth and clothing is important for many applications
such as virtual reality, crowd simulation, games and software for online clothes shopping.
A large number of polygons are necessary to depict the highly
exible nature of
cloth with wrinkling and frequent changes in its curvature. In combination with the
physical calculations which model the deformations, the effort required to simulate
cloth in detail is very computationally expensive resulting in much diffculty for its
realistic simulation at interactive frame rates. Real-time cloth simulations can lack
quality and realism compared to their offline counterparts, since coarse meshes must
often be employed for performance reasons.
The focus of this thesis is to develop techniques to allow the real-time simulation of
realistic cloth and clothing. Adaptive meshes have previously been developed to act as
a bridge between low and high polygon meshes, aiming to adaptively exploit variations
in the shape of the cloth. The mesh complexity is dynamically increased or refined to
balance quality against computational cost during a simulation. A limitation of many
approaches is they do not often consider the decimation or coarsening of previously
refined areas, or otherwise are not fast enough for real-time applications.
A novel edge-based adaptive mesh is developed for the fast incremental refinement
and coarsening of a triangular mesh. A mass-spring network is integrated into
the mesh permitting the real-time adaptive simulation of cloth, and techniques are
developed for the simulation of clothing on an animated character
Realistic Visualization of Accessories within Interactive Simulation Systems for Garment Prototyping
In virtual garment prototyping, designers create a garment design by using Computer Aided Design (CAD). In difference to traditional CAD the word "aided" in this case refers to the computer replicating real world behavior of garments. This allows the designer to interact naturally with his design. The designer has a wide range of expressions within his work. This is done by defining details on a garment which are not limited to the type of cloth used. The way how cloth patterns are sewn together and the style and usage of details of the cloth's surface, like appliqués, have a strong impact on the visual appearance of a garment to a large degree. Therefore, virtual and real garments usually have a lot of such surface details.
Interactive virtual garment prototyping itself is an interdisciplinary field. Several problems have to be solved to create an efficiently usable real-time virtual prototyping system for garment manufacturers.
Such a system can be roughly separated into three sub-components. The first component deals with acquisition of material and other data needed to let a simulation mimic plausible real world behavior of the garment. The second component is the garment simulation process itself. Finally, the third component is centered on the visualization of the simulation results. Therefore, the overall process spans several scientific areas which have to take into account the needs of each other in order to get an overall interactive system. In my work I especially target the third section, which deals with the visualization.
On the scientific side, the developments in the last years have shown great improvements on both speed and reliability of simulation and rendering approaches suitable for the virtual prototyping of garments.
However, with the currently existing approaches there are still many problems to be solved, especially if interactive simulation and visualization need to work together and many object and surface details come into play. This is the case when using a virtual prototyping in a productive environment.
The currently available approaches try to handle most of the surface details as part of the simulation. This generates a lot of data early in the pipeline which needs to be transferred and processed, requiring a lot of processing time and easily stalls the pipeline defined by the simulation and visualization system. Additionally, real world garment examples are already complicated in their cloth arrangement alone.
This requires additional computational power. Therefore, the interactive garment simulation tends to lose its capability to allow interactive handling of the garment.
In my work I present a solution, which solves this problem by moving the handling of design details from the simulation stage entirely to a completely GPU based rendering stage. This way, the behavior of the garment and its visual appearance are separated. Therefore, the simulation part can fully concentrate on simulating the fabric behavior, while the visualization handles the placing of surface details lighting, materials and self-shadowing.
Thus, a much higher degree of surface complexity can be achieved within an interactive virtual prototyping system as can be done with the current existing approaches
Dressing Avatars: Deep Photorealistic Appearance for Physically Simulated Clothing
Despite recent progress in developing animatable full-body avatars, realistic
modeling of clothing - one of the core aspects of human self-expression -
remains an open challenge. State-of-the-art physical simulation methods can
generate realistically behaving clothing geometry at interactive rates.
Modeling photorealistic appearance, however, usually requires physically-based
rendering which is too expensive for interactive applications. On the other
hand, data-driven deep appearance models are capable of efficiently producing
realistic appearance, but struggle at synthesizing geometry of highly dynamic
clothing and handling challenging body-clothing configurations. To this end, we
introduce pose-driven avatars with explicit modeling of clothing that exhibit
both photorealistic appearance learned from real-world data and realistic
clothing dynamics. The key idea is to introduce a neural clothing appearance
model that operates on top of explicit geometry: at training time we use
high-fidelity tracking, whereas at animation time we rely on physically
simulated geometry. Our core contribution is a physically-inspired appearance
network, capable of generating photorealistic appearance with view-dependent
and dynamic shadowing effects even for unseen body-clothing configurations. We
conduct a thorough evaluation of our model and demonstrate diverse animation
results on several subjects and different types of clothing. Unlike previous
work on photorealistic full-body avatars, our approach can produce much richer
dynamics and more realistic deformations even for many examples of loose
clothing. We also demonstrate that our formulation naturally allows clothing to
be used with avatars of different people while staying fully animatable, thus
enabling, for the first time, photorealistic avatars with novel clothing.Comment: SIGGRAPH Asia 2022 (ACM ToG) camera ready. The supplementary video
can be found on
https://research.facebook.com/publications/dressing-avatars-deep-photorealistic-appearance-for-physically-simulated-clothing
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