Interactive Sketching of Mannequin Poses

It can be easy and even fun to sketch humans in different poses. In contrast, creating those same poses on a 3D graphics 'mannequin' is comparatively tedious. Yet 3D body poses are necessary for various downstream applications. We seek to preserve the convenience of 2D sketching while giving users of different skill levels the flexibility to accurately and more quickly pose/refine a 3D mannequin. At the core of the interactive system, we propose a machine-learning model for inferring the 3D pose of a CG mannequin from sketches of humans drawn in a cylinder-person style. Training such a model is challenging because of artist variability, a lack of sketch training data with corresponding ground truth 3D poses, and the high dimensionality of human pose-space. Our unique approach to synthesizing vector graphics training data underpins our integrated ML-and-kinematics system. We validate the system by tightly coupling it with a user interface, and by performing a user study, in addition to quantitative comparisons

HairBrush for Immersive Data-Driven Hair Modeling

International audienceWhile hair is an essential component of virtual humans, it is also one of the most challenging digital assets to create. Existing automatic techniques lack the generality and flexibility to create rich hair variations, while manual authoring interfaces often require considerable artistic skills and efforts, especially for intricate 3D hair structures that can be difficult to navigate. We propose an interactive hair modeling system that can help create complex hairstyles in minutes or hours that would otherwise take much longer with existing tools. Modelers, including novice users, can focus on the overall hairstyles and local hair deformations, as our system intelligently suggests the desired hair parts. Our method combines the flexibility of manual authoring and the convenience of data-driven automation. Since hair contains intricate 3D structures such as buns, knots, and strands, they are inherently challenging to create using traditional 2D interfaces. Our system provides a new 3D hair author-ing interface for immersive interaction in virtual reality (VR). Users can draw high-level guide strips, from which our system predicts the most plausible hairstyles via a deep neural network trained from a professionally curated dataset. Each hairstyle in our dataset is composed of multiple variations, serving as blend-shapes to fit the user drawings via global blending and local deformation. The fitted hair models are visualized as interactive suggestions that the user can select, modify, or ignore. We conducted a user study to confirm that our system can significantly reduce manual labor while improve the output quality for modeling a variety of head and facial hairstyles that are challenging to create via existing techniques

Generation of 3D characters from existing cartoons and a unified pipeline for animation and video games.

Despite the remarkable growth of 3D animation in the last twenty years, 2D is still popular today and often employed for both films and video games. In fact, 2D offers important economic and artistic advantages to production. In this thesis has been introduced an innovative system to generate 3D character from 2D cartoons, while maintaining important 2D features in 3D as well. However, handling 2D characters and animation in a 3D environment is not a trivial task, as they do not possess any depth information. Three different solutions have been proposed in this thesis. A 2.5D modelling method, which exploits billboarding, parallax scrolling and 2D shape interpolation to simulate the depth between the different body parts of the characters. Two additional full 3D solution have been presented. One based on inflation and supported by a surface registration method, and one that produces more accurate approximations by using information from the side views to solve an optimization problem. These methods have been introduced into a new unified pipeline that involves a game engine, and that could be used for animation and video games production. A unified pipeline introduces several benefits to animation production for either 2D and 3D content. On one hand, assets can be shared for different productions and media. On the other hand, real-time rendering for animated films allows immediate previews of the scenes and offers artists a way to experiment more during the making of a scene

Multi-agent simulation: new approaches to exploring space-time dynamics in GIS

As part of the long term quest to develop more disaggregate, temporally dynamic models of spatial behaviour, micro-simulation has evolved to the point where the actions of many individuals can be computed. These multi-agent systems/simulation(MAS) models are a consequence of much better micro data, more powerful and user-friendly computer environments often based on parallel processing, and the generally recognised need in spatial science for modelling temporal process. In this paper, we develop a series of multi-agent models which operate in cellular space.These demonstrate the well-known principle that local action can give rise to global pattern but also how such pattern emerges as the consequence of positive feedback and learned behaviour. We first summarise the way cellular representation is important in adding new process functionality to GIS, and the way this is effected through ideas from cellular automata (CA) modelling. We then outline the key ideas of multi-agent simulation and this sets the scene for three applications to problems involving the use of agents to explore geographic space. We first illustrate how agents can be programmed to search route networks, finding shortest routes in adhoc as well as structured ways equivalent to the operation of the Bellman-Dijkstra algorithm. We then demonstrate how the agent-based approach can be used to simulate the dynamics of water flow, implying that such models can be used to effectively model the evolution of river systems. Finally we show how agents can detect the geometric properties of space, generating powerful results that are notpossible using conventional geometry, and we illustrate these ideas by computing the visual fields or isovists associated with different viewpoints within the Tate Gallery.Our forays into MAS are all based on developing reactive agent models with minimal interaction and we conclude with suggestions for how these models might incorporate cognition, planning, and stronger positive feedbacks between agents

Efficient sketch-based 3D character modelling.

Sketch-based modelling (SBM) has undergone substantial research over the past two decades. In the early days, researchers aimed at developing techniques useful for modelling of architectural and mechanical models through sketching. With the advancement of technology used in designing visual effects for film, TV and games, the demand for highly realistic 3D character models has skyrocketed. To allow artists to create 3D character models quickly, researchers have proposed several techniques for efficient character modelling from sketched feature curves. Moreover several research groups have developed 3D shape databases to retrieve 3D models from sketched inputs. Unfortunately, the current state of the art in sketch-based organic modelling (3D character modelling) contains a lot of gaps and limitations. To bridge the gaps and improve the current sketch-based modelling techniques, this research aims to develop an approach allowing direct and interactive modelling of 3D characters from sketched feature curves, and also make use of 3D shape databases to guide the artist to create his / her desired models. The research involved finding a fusion between 3D shape retrieval, shape manipulation, and shape reconstruction / generation techniques backed by an extensive literature review, experimentation and results. The outcome of this research involved devising a novel and improved technique for sketch-based modelling, the creation of a software interface that allows the artist to quickly and easily create realistic 3D character models with comparatively less effort and learning. The proposed research work provides the tools to draw 3D shape primitives and manipulate them using simple gestures which leads to a better modelling experience than the existing state of the art SBM systems

Character Body Expression in 3D Computer Animation: a New Posing Approach.

Creation of 3D character animations is a complex and time-consuming process, and the character animator has to simultaneously consider a multitude of factors in order to create high quality expressive animation. The 12 Principles of Animation are traditionally considered as the main guidelines for creating high-grade character animation. The main focus of this research is the process of animating the 3D character’s body expression and the animator’s practice, particularly the Posing phase of the animation process. Although posing is not one of the 12 Principles of Animation, it can be considered as the superposition of a subset of those principles that the animator has to keep in mind, while creating key-poses for any specific movement of an animated character. Additional factors that should be considered by the animator during the Posing stage are body language and acting, along with the technicalities of the 3D character manipulation. Hence, Posing is regarded as an intricate process, making it rather challenging for the animator to avoid involuntary neglect of the large number of the aforementioned characteristics. This aspect of the 3D animation process is extremely important for the final creative result of the animation, in terms of character's expression, because if the key-poses are not well defined, the computer may not be able to generate sufficiently expressive animation. This would often result in work that may be subjectively judged as lower quality animations. This research developed the hypothesis that the key to create more expressive 3D character animation is located within Posing, in the Animation Blocking phase of the process. This thesis proposes that a systematisation of the Posing procedure taking advantage of certain Traditional Animation, Fine Arts and Acting concepts and their underlying rationale, can greatly benefit the animator. This thesis presents a new posing approach to 3D character animation, as a conceptual guideline which promotes the arrangement of the body parts into naturalistic patterns of expression. This is achieved by combining the concepts of Power Centre, Line of Action, Contrapposto and Serpentine Line in a systematic way, around a conceptual flow of force. These comprehensible high-level concepts make Posing and the animation process less complicated and more accessible. This allows animators of different levels to create more believable character body expressions in an easier and less time-consuming fashion, introducing better methods of more efficient workflows resulting in improved creative results over shorter periods of time. It is also demonstrated how the aforementioned concepts can be applied to a variety of animation styles – ranging from the more realistic to the more cartoonish ones. A prototype of a 3D Pose Tool was also developed, based on the rationale of the proposed approach, with the objective of being used as a visual guide for generation of new poses to be included in the case studies. Additionally, this tool produces visual evidence in the analysis of specific good and bad examples of character posing. This thesis, therefore, makes the argument that the proposed solution – whether accompanied with the complementary 3D Pose Tool or not – gives the animator the possibility to work the character body expression as a whole. Thus, avoiding stiffness and ensuring that the essential steps of posing are not neglected in the process. This was demonstrated with several cases, which give evidence of the usefulness of the approach as a contribution to create more expressive character animation and to produce it in a more efficient way