411 research outputs found
Interactive Animation of Dynamic Manipulation
No full textLifelike animation of manipulation must account for the dynamicinteraction between animated characters, objects, and their environment. Failing to do so would ignore the often significant effects objectshave on the motion of the character. For example, lifting a heavy objectwould appear identical to lifting a light one. Physical simulationhandles such interaction correctly, with a principled approach thatadapts easily to different circumstances, changing environments, andunexpected disturbances. Our work shows how to control lifelike animatedcharacters so that they accomplish manipulation tasks within aninteractive physical simulation. Our new multi-task control algorithmsimplifies descriptions of manipulation by supporting prioritized goalsin both the joint space of the character and the task-space of theobject. The end result is a versatile algorithm that incorporatesrealistic force limits and recorded motion postures to portray lifelikemanipulation automatically
Style Translation for Human Motion (Supplemental Material)
No full textStyle translation is the process of transforming an input motion into a new style while preserving its original content. This problem is motivated by the needs of interactive applications, which require rapid processing of captured performances. Our solution learns to translate by analyzing differences between performances of the same content in input and output styles. It relies on a novel correspondence algorithm to align motions, and a linear time-invariant model to represent stylistic differences. Once the model is estimated with system identification, our system is capable of translating streaming input with simple linear operations at each frame
Multiobjective Control with Frictional Contacts
No full textStanding is a fundamental skill mastered by humans and animals alike. Although easy for adults, it requires careful and deliberate manipulation of contact forces. The variation in contact configuration (e.g., standing on one foot, on uneven ground, or while holding on for support) presents a difficult challenge for interactive simulation of humans and animals, especially while performing tasks in the presence of external disturbances. We describe an analytic approach for control of standing in three-dimensional simulations based upon local optimization. At any point in time, the control system solves a quadratic program to compute actuation by maximizing the performance of multiple motion objectives subject to constraints imposed by actuation limits and contact configuration. This formulation is suitable for interactive animation and it adapts to the proportions of any character model in any non-planar, frictional contact configuration.Eurographics/SIGGRAPH Symposium on Computer Animatio
Guided TimeWarping for Motion Editing
No full textTime warping allows users to modify timing without affecting poses. It has many applications in animation systems for motion editing, such as refining motions to meet new timing constraints or modifying the acting of animated characters. However, time warping typically requires many manual adjustments to achieve the desired results. We present a technique which simplifies this process by allowing time warps to be guided by a provided reference motion. Given few timing constraints, it computes a warp that both satisfies these constraints and maximizes local timing similarities to the reference. The algorithm is fast enough to incorporate into standard animation workflows. We apply the technique to two common tasks: preserving the natural timing of motions under new time constraints and modifying the timing of motions for stylistic effects.Eurographics/SIGGRAPH Symposium on Computer Animatio
Example-Based Control of Human Motion
No full textIn human motion control applications, the mapping between a control specification and an appropriate target motion often defies an explicit encoding. We present a method that allows such a mapping to be defined by example, given that the control specification is recorded motion. Our method begins by building a database of semantically meaningful instances of the mapping, each of which is represented by synchronized segments of control and target motion. A dynamic programming algorithm can then be used to interpret an input control specification in terms of mapping instances. This interpretation induces a sequence of target segments from the database, which is concatenated to create the appropriate target motion. We evaluate our method on two examples of indirect control. In the first, we synthesize a walking human character that follows a sampled trajectory. In the second, we generate a synthetic partner for a dancer whose motion is acquired through motion capture
Practical Color-Based Motion Capture
No full textMotion capture systems have been widely used for high quality content creation and virtual reality but are rarely used in consumer applications due to their price and setup cost. In this paper, we propose a motion capture system built from commodity components that can be deployed in a matter of minutes. Our approach uses one or more webcams and a color shirt to track the upper-body at interactive rates. We describe a robust color calibration system that enables our color-based tracking to work against cluttered backgrounds and under multiple illuminants. We demonstrate our system in several real-world indoor and outdoor settings
The people behind the papers - Yonit Maroudas-Sacks and Marko Popovic
No full textDuring Hydra regeneration, supracellular actomyosin fibres are disoriented at two distinct foci of the regenerating tissue. These sites of nematic topological defects eventually form the new head and foot of the regenerated animal. In a new study, Yonit MaroudasSacks, Marko Popovic, Kinneret Keren and colleagues propose a positive-feedback loop that incorporates fibre organisation, tissue strain and morphogen gradients to promote head organiser formation. To find out more about the work, we caught up with first author Yonit Maroudas-Sacks and co-corresponding author Marko Popovic, Group Leader at the Max Planck Institute for the Physics of Complex Systems, Germany
Style Translation for Human Motion
No full textStyle translation is the process of transforming an input motion into a new style while preserving its original content. This problem is motivated by the needs of interactive applications, which require rapid processing of captured performances. Our solution learns to translate by analyzing differences between performances of the same content in input and output styles. It relies on a novel correspondence algorithm to align motions, and a linear time-invariant model to represent stylistic differences. Once the model is estimated with system identification, our system is capable of translating streaming input with simple linear operations at each frame
Scandergbeg negli scritti di Jovan Sterija Popovic
No full textNel presente lavoro sono analizzati gli scritti del drammaturgo serbo Jovan Sterija Popović (1806-1856) dedicati all’eroe albanese Giorgio Castriota Scanderbeg (1405-1468): si tratta della biografia "Život i vitežka voevanija slavnog kneza epirskoga Đorđa Kastriota Skenderbega" (“La vita e i combattimenti cavallereschi del celebre condottiero epirota Giorgio Castriota Scanderbeg”, Buda 1828) e del dramma "Skenderbeg", composto intorno al 1847-48 e pubblicato postumo (Pančevo 1889). Nel ricostruire le fonti utilizzate dall’autore serbo per i suoi testi, la ricerca si focalizza in particolare sulla figura storica del condottiero albanese, qui oggetto di una rilettura che ne mette in luce il ruolo effettivo, e non solo simbolico, nella storia moderna degli slavi meridionali. This paper examines the writings of the Serbian playwright Jovan Sterija Popović (1806-1856) on the Albanian hero George Castriot Skanderbeg (1405-1468). Popović’s biography of Skanderbeg entitled Život i vitežka voevanija slavnog kneza epirskoga Đorđa Kastriota Skenderbega (“The Life and the Chivalry of the Famous Epirus Leader George Castriot Skanderbeg”, Buda 1828) and the drama Skenderbeg, written around 1847-48 and published posthumously (Pančevo 1889) are explored. The sources for the biography and consequently also for the drama are identified and the significance that the historical and poetic figure of the Albanian leader has in the modern history of the Southern Slavs is highlighted
Real-time control of physically based simulations using gentle forces
No full textRecent advances have brought real-time physically based simulation within reach, but simulations are still difficult to control in real time. We present interactive simulations of passive systems such as deformable solids or fluids that are not only fast, but also directable: they follow given input trajectories while simultaneously reacting to user input and other unexpected disturbances. We achieve such directability using a real-time controller that runs in tandem with a real-time physically based simulation. To avoid stiff and over-controlled systems where the natural dynamics are overpowered, the injection of control forces has to be minimized. This search for gentle forces can be made tractable in real-time by linearizing the system dynamics around the input trajectory, and then using a time-varying linear quadratic regulator to build the controller. We show examples of controlled complex deformable solids and fluids, demonstrating that our approach generates a requested fixed outcome for reasonable user inputs, while simultaneously providing runtime motion variety
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