349 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
CTSN: Predicting Cloth Deformation for Skeleton-based Characters with a Two-stream Skinning Network
We present a novel learning method to predict the cloth deformation for
skeleton-based characters with a two-stream network. The characters processed
in our approach are not limited to humans, and can be other skeletal-based
representations of non-human targets such as fish or pets. We use a novel
network architecture which consists of skeleton-based and mesh-based residual
networks to learn the coarse and wrinkle features as the overall residual from
the template cloth mesh. Our network is used to predict the deformation for
loose or tight-fitting clothing or dresses. We ensure that the memory footprint
of our network is low, and thereby result in reduced storage and computational
requirements. In practice, our prediction for a single cloth mesh for the
skeleton-based character takes about 7 milliseconds on an NVIDIA GeForce RTX
3090 GPU. Compared with prior methods, our network can generate fine
deformation results with details and wrinkles.Comment: 13 page
Real-Time Cloth Simulation on Virtual Human Character Using Enhanced Position Based Dynamic Framework Technique
كانت محاكاة القماش والرسوم المتحركة موضوعًا للبحث منذ منتصف الثمانينيات في مجال رسومات الكمبيوتر. إن فرض عدم الضغط مهم جدًا في محاكاة الوقت الفعلي. على الرغم من أن هناك إنجازات كبيرة في هذا الصدد ، إلا أنها لا تزال تعاني من استهلاك الوقت غير الضروري في خطوات معينة شائعة في التطبيقات في الوقت الفعلي. يطور هذا البحث محاكاة قماش في الوقت الفعلي لشخصية بشرية افتراضية مرتدية ملابس. وقد حققت هذه المخطوطة الاهداف في محاكاة القماش على الشخصية الافتراضة من خلال تعزيز إطار الديناميكيات القائمة على الموقع من خلال حساب سلسلة من القيود الموضعية التي تنفذ كثافات ثابتة. أيضا ، يتم تنفيذ التصادم الذاتي والاصطدام مع الكبسولات المتحركة لتحقيق قماش سلوك واقعي على غرار الرسوم المتحركة. وذلك لتمكين عدم قابلية المقارنة والالتقاء مقارنة بمذيبات دالة تشوه جيب التمام عند التنفيذ ، نحقق تصادمًا محسنًا بين الملابس ، ومزامنة الرسوم المتحركة مع محاكاة القماش وتحديد خصائص القماش للحصول على أفضل النتائج الممكنة. لذلك ، تم تحقيق محاكاة القماش في الوقت الحقيقي ، مع إخراج معقول ، على الشخصية الافتراضية المتحركة. ندرك أن طريقتنا المقترحة يمكن أن تكون بمثابة استكمال للبحوث السابقة في حقل ملابس الشخصيات الافتراضية. Cloth simulation and animation has been the topic of research since the mid-80's in the field of computer graphics. Enforcing incompressible is very important in real time simulation. Although, there are great achievements in this regard, it still suffers from unnecessary time consumption in certain steps that is common in real time applications. This research develops a real-time cloth simulator for a virtual human character (VHC) with wearable clothing. This research achieves success in cloth simulation on the VHC through enhancing the position-based dynamics (PBD) framework by computing a series of positional constraints which implement constant densities. Also, the self-collision and collision with moving capsules is implemented to achieve realistic behavior cloth modelled on animated characters. This is to enable comparable incompressibility and convergence to raised cosine deformation (RCD) function solvers. On implementation, this research achieves optimized collision between clothes, syncing of the animation with the cloth simulation and setting the properties of the cloth to get the best results possible. Therefore, a real-time cloth simulation, with believable output, on animated VHC is achieved. This research perceives our proposed method can serve as a completion to the game assets clothing pipeline
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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