SCA 17: Posters

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https://diglib.eg.org/handle/10.2312/2631999

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Sketch-Based 3D Hair Posing by Contour Drawings
(ACM, 2017) Seki, Shogo; Igarashi, Takeo; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We propose a sketch-based method for posing a three-dimensional (3D) hair model that enables artists to create attractive hairstyles more easily and intuitively. The system takes partial contour drawings of a preferred hair shape to modify the rig parameters so that the hair model fits into the sketch. Our method consists of two parts: flow extraction from a sketch and pose construction using the flow. The method was evaluated by a user study and an interview with a professional 3D artist.
Motion Retargeting to Preserve Spatial Relationship between Skinned Characters
(ACM, 2017) Jin, Taeil; Kim, Meekyung; Lee, Sung-Hee; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
Applying motion capture data for multi-person interaction to virtual characters is challenging because one needs to preserve interaction semantics in addition to satisfying the general requirements for motion retargeting, such as preventing penetration and preserving naturalness. An e cient method for representing the scene semantics of interaction motions is to de ne the spatial relationships between body parts of characters. However, existing methods of this kind consider only character skeleton, and thus may require post-processing to re ne the interaction motions and remove artifacts from the viewpoint of skin meshes. This paper proposes a novel method for retargeting interaction motions with respect to character skins. To this end, we introduce the aura mesh surrounding a character's skin in order to represent skin-level spatial relationships between body parts. Using the aura mesh, we can retarget interaction motions while preserving skin-level spatial relationships and reducing skin inter-penetrations.
Position-Based Multi-Agent Dynamics for Real-Time Crowd Simulation
(ACM, 2017) Weiss, Tomer; Litteneker, Alan; Jiang, Chenfanfu; Terzopoulos, Demetri; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
Exploiting the e ciency and stability of Position-Based Dynamics (PBD), we introduce a novel crowd simulation method that runs at interactive rates for hundreds of thousands of agents. Our method enables the detailed modeling of per-agent behavior in a Lagrangian formulation. We model short-range and long-range collision avoidance constraints to simulate both sparse and dense crowds. The local short-range interaction is represented with collision and frictional contact between agents, as in the discrete simulation of granular materials.We incorporate a cohesion model for modeling collective behaviors and propose a new constraint for dealing with potential future collisions. Our new real-time crowd simulation method is suitable for use in interactive games.
The Stretch-Engine: A Method for Adjusting the Exaggeration of Bipedal Characters Through Squash and Stretch
(ACM, 2017) Ibrahim, Zaid H.; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
This paper describes a new method to control changes in a character's form during exaggeration, through squash and stretch (SS). The Stretch-Engine is the result of this method, designed to be integrated into an existing animation system, Maya. The Stretch- Engine is a three-part system where the first is a bipedal-humanoid rig with controls necessary for animation and the ability to SS its limbs. The second is a set of rules determined from studying Looney Tunes animation to create a range of SS. The third is a user interface that allows users to control changes in SS using 3D curves created within the Maya interface.
Human Grasping Interaction Capture and Analysis
(ACM, 2017) Verider, Benjamin; Andrews, Sheldon; Kry, Paul G.; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We design a system to capture, clean, and segment a high quality database of hand based grasping and manipulation. We capture interactions with a large collection of everyday objects. Optical marker-based motion capture and glove data are combined in a physics-based filter to improve the quality of thumb motion. Sensors stitched into our glove provide recordings of the pressure image across the fingers and the palm. We evaluate di erent segmentation techniques for processing motion and pressure data. Finally, we describe examples that explain how the data will be useful in applications such as virtual reality and the design of physics-based control of virtual and robotic hands.
Comparing Traditional Key Frame and Hybrid Animation
(ACM, 2017) Ahlström, Eric; Holmqvist, Lucas; Goswami, Prashant; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
In this research the authors explore a hybrid approach which uses the basic concept of key frame animation together with procedural animation to reduce the number of key frames needed for an animation clip. The two approaches are compared by conducting an experiment where the participating subjects were asked to rate them based on their visual appeal.
Regression-Based Locating Landmark on Dynamic Humans
(ACM, 2017) Jang, Deok-Kyeong; Lee, Sung-Hee; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We present a novel framework that consists of two-level regressors for finding correlations between human shapes and landmark positions in both body part and holistic scales. To this end, we first develop pose invariant coordinates of landmarks that represent both local and global shape features by using the pose invariant local shape descriptors and their spatial relationships. Our body part-level regression deals with the shape features from only those body parts corresponding to a certain landmark. For this, we develop a method that identi es such body parts per landmark, by using geometric shape dictionary obtained through the bag of features method. Our method is nearly automatic, requiring human assistance only once to di erentiate the left and right sides, and shows the prediction accuracy comparable to or better than those of existing methods, with a test data set containing a large variation of human shapes and poses.
Online Compression of Rigid Body Simulations using Physics-Inspired Interpolation
(ACM, 2017) Jeruzalski, Timothy; Fiume, Eugene; Jacobson, Alec; Levin, David I.W.; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
Methods to compress simulation data are invaluable as they facilitate efficient transmission along the visual effects pipeline, fast and efficient replay of simulations for visualization and enable storage of scientific data. However, all current approaches to compressing simulation data require access to the entire dynamic simulation, leading to large memory requirements and additional computational burden. In this paper we perform physics-based simulation compression in an online fashion, requiring access to only a narrow window of simulation data at a time and achieving good agreement with the original simulation.
Automated Regression Tests for Character Animation Systems
(ACM, 2017) Mohr-Daurat, Hubert; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We present a process to verify code changes in an animation system by using regression tests which guarantee to cover every combination of animation features used in production. For this, we need to identify the untested combinations of animation features, create an immutable set of animation data which is representative of it, and when performing the tests, automatically compare the difference in the generated poses at each revision of the code.
Marionette Show Using Quadrotors
(ACM, 2017) Kim, Yongsung; Choi, Myung Geol; Lee, Jehee; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
A marionett?e show is a play with the puppet controlled from above using wires by human. One ends of the wires are connected on di?erent joints of the marione?e, and the other ends are tied on a control stick. ?e marione?ist makes the puppet move by elab- orately manipulating the control stick. By the marione?ttist, the puppet looks like a living creature, sometimes walking, jumping, talking and dancing. And through the performances of these pup- pet, it gives pleasure to the audience. However, this technique requires a lot of practice, and even a slight shake of the control stick causes a large twisting or swinging of the wires, which results in a completely di?erent motion from the original intention. Our goals are to analyze the puppet shows of skilled marionett?ists, to reproduce them using quadrotors instead of human hands, and ?nally to create new shows. ?adrotor has simple mechanics, high maneuverability and very easy to control, so it has been used in various research topics over the past few years. More recently, fun and challenging tasks such as pole acrobatics [Brescianini et al. 2013], ball juggling [Mller et al. 2011] and ball throwing [Ritz et al. 2012] have been carried out using the quadrotor.
Cubification and Animation of Artistic Shapes
(ACM, 2017) Corker-Marin, Quentin; Adzhiev, Valery; Pasko, Alexander; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
This poster describes an original approach to creating static and dynamic sculptures in a cubist style.We propose a novel method for faceting and local distortion thus adding cubist features and generating time-variant sculptural shapes. We introduce the concept of a 4D cubist camera for blending multiple projections from 4D spacetime to 3D space.We describe a practical pipeline embracing all the main phases of production of static and dynamic cubist shapes. The proposed techniques are implemented and experimental results are presented.
Coordinating Full-Body Interactions with the Environment
(ACM, 2017) Juarez-Perez, Alain; Kallmann, Marcelo; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We present a methodology for synthesizing coordinated full-body motions in order to achieve autonomous virtual characters capable of interacting with the environment while walking. Starting with a parameterized walking controller and a set of mocap examples our method is then able to coordinate upper-body interactions with the walking controller in order to achieve full-body object interactions in generalized situations.
Understanding Spatial Perception and Visual Modes in the Review of Architectural Designs
(ACM, 2017) Usman, Muhammad; Haworth, Brandon; Berseth, Glen; Kapadia, Mubbasir; Faloutsos, Petros; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We investigate how a person's perception of space in di erent visual modes relates to common computational spatial measures for environment designs. The three spatial measures, grounded in Space-Syntax analysis, are used to capture di erent aspects of a design such as visibility, accessibility, and organization.We perform two studies involving novice users and the experts. First, we conduct a perceptual study to find out how novice users perceive these spatial measures when exploring and environment design using di erent visual modes including 2D blueprints, 3D first-person view, and room-scale virtual reality. A correlation analysis between the users' perceptual ratings and the spatial measures indicates that virtual reality is the most e ective of the three methods. We conclude that virtual reality provides the requisite fidelity needed to su ciently capture subtle aspects of 3D space, needed to perceive accessibility, visibility, and organization of an environment. On the other hand, 2D blueprints and 3D first-person exploration often fail to convey the spatial measures. In the second study, experts are asked to evaluate and rank the design blueprints for each spatial measure. The expert observations are in strong agreement with the spatial measures for accessibility and organization, but not for visibility in some cases. This indicates that even experts have difficulty understanding spatial aspects of an architectural design from 2D blueprints alone.
Attachment-Based Character Deformation
(ACM, 2017) Toothman, Nick; Neff, Michael; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
While advancements have made it easier to work with digital characters, it remains difficult to author animations that display the free and highly expressive shape change that characterize hand-drawn animation.We present a deformation method that combines skeletal control and free shape change in a single framework, along with an intuitive, sketch-based interface. By finding attachment points between the mesh and skeleton, we enable con gurable skeleton and surface-based deformations, and avoid common skinning artifacts. Use of sketch-based interfaces and graphics hardware make both skeletal and mesh deformation simple to control and fast enough for interactive use.
Volumetric Muscle Controller
(ACM, 2017) Lee, Seunghwan; Mitchell, Nathan; Aanjaneya, Mridul; Sifakis, Eftychios; Lee, Jehee; Bernhard Thomaszewski and KangKang Yin and Rahul Narain
We describe a controller with a fully integrated musculoskeletal model actuated by more than a hundred muscles. Inspired by a QP-based control algorithm, we improved the algorithm to control the volumetric muscles directly. Furthermore, the highly-detailed musculoskeleton was modeled using a non-manifold method and a computation time was e ectively reduced through implicit jacobian computation. Our entire system can simulate the musculoskeleton model with detailed volumetric muscles in a feasible computation time.

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