Ehtzaz Chaudhry

Character Skin Deformation: A Survey

Skin deformation plays a very important role in creating realistic character animation. A lot of research efforts have been devoted to the development of skin deformation techniques. The paper provides a survey of various techniques and classify them into three major categories; surface-based, volume-based and curve-based techniques. Surface based techniques are divided into purely geometric and physics-based. Volume-based techniques are grouped into purely geometric, anatomy based, and physics-based. Curve-based techniques are classified as free form deformation, purely geometric sweep deformation, cross section method; physics based sweep deformation, static curve-based skin deformation, and dynamic curve-based skin deformation. For each group, a representative technique is introduced. The strengths and weaknesses of each technique are analysed. Finally, some future research directions are discussed.

SMI 2013: Shape modeling for animated characters using ordinary differential equations

In this paper, we develop a new approach to animate skin deformation of character models. It aims to combine the strengths of joint-based approaches, physics-based algorithms and curve-based surface modeling methods together for efficient and realistic animation of skin deformation. We first transform the deformation of skin surfaces of character models into that of the curves defining the skin surfaces, and introduce a mathematical model consisting of a vector-valued fourth order ordinary differential equation and boundary conditions to describe the curve deformation. In order to achieve capacity and high animation efficiency, we propose an efficient finite difference solution of the mathematical model, and apply our proposed solution to animate skin deformation of character models. The application examples demonstrate that our proposed approach can create realistic skin deformations for real-time character animation.

Dynamic skin deformation using finite difference solutions for character animation

Abstract We present a new skin deformation method to create dynamic skin deformations in this paper. The core elements of our approach are a dynamic deformation model, an efficient data-driven finite difference solution, and a curve-based representation of 3D models. We first reconstruct skin deformation models at different poses from the taken photos of a male human arm movement to achieve real deformed skin shapes. Then, we extract curves from these reconstructed skin deformation models. A new dynamic deformation model is proposed to describe physics of dynamic curve deformations, and its finite difference solution is developed to determine shape changes of the extracted curves. In order to improve visual realism of skin deformations, we employ data-driven methods and introduce skin shapes at the initial and final poses into our proposed dynamic deformation model. Experimental examples and comparisons made in this paper indicate that our proposed dynamic skin deformation technique can create realistic deformed skin shapes efficiently with a small data size.

Physics and example based skin deformations for character animation

We present a fast physics and example based skin deformation method for character animation in this paper. The main idea is to represent the skin surface and its deformations with a group of curves whose computation incurs much less computing overheads than the direct surface-based approach. A fourth order ordinary differential equation is introduced to describe the deformations of the curves between two example skin shapes which relates geometric and physical properties and externally applied forces to shape changes of the curves. The skin deformation is determined from these deformed curves. Several examples are given in this paper to demonstrate the application of the method.

Surface modeling with boundary constraints and partial differential equations

In this paper, we present a method to create and manipulate free form surfaces. A surface is generated from boundary constraints through a vector-valued fourth order partial differential equation involving an externally applied force. In addition to this function, the boundary constraints and the externally applied force also serve as shape manipulation tools. The proposed approach is applied in surface creation, surface manipulation, surface rebuilding and surface animation. It can tackle the problems of tangential continuity in patch modeing and is cheap to compute. The examples given in this paper indicate that our proposed method can create and manipulate free from surfaces easily and quickly.

Automatic Generation of Dynamic Skin Deformation for Animated Characters

Since non-automatic rigging requires heavy human involvements, and various automatic rigging algorithms are less efficient in terms of computational efficiency, especially for current curve-based skin deformation methods, identifying the iso-parametric curves and creating the animation skeleton requires tedious and time-consuming manual work. Although several automatic rigging methods have been developed, but they do not aim at curve-based models. To tackle this issue, this paper proposes a new rigging algorithm for automatic generation of dynamic skin deformation to quickly identify iso-parametric curves and create an animation skeleton in a few milliseconds, which can be seamlessly used in curve-based skin deformation methods to make the rigging process fast enough for highly efficient computer animation applications.

Realistic Texture Synthesis for Point-based Fruitage Phenotype

Although current 3D scanner technology can acquire textural images from a point model, visible seams in the image, inconvenient data acquisition and occupancy of a large space during use are points of concern for outdoor fruit models. In this paper, an SPSDW (simplification and perception based subdivision followed by down-sampling weighted average) method is proposed to balance memory usage and texture synthesis quality using a crop fruit, such as apples, as a research subject for a point-based fruit model. First, the quadtree method is improved to make splitting more efficient, and a reasonable texton descriptor is defined to promote query efficiency. Then, the color perception feature is extracted from the image for all pixels. Next, an advanced sub-division scheme and down-sampling strategy are designed to optimize memory space. Finally, a weighted oversampling method is proposed for high-quality texture mixing. This experiment demonstrates that the SPSDW method preserves the mixed texture more realistically and smoothly and preserves color memory up to 94%, 84.7% and 85.7% better than the two-dimesional processing, truncating scalar quantitative and color vision model methods, respectively.

Semantic modeling of indoor scenes with support inference from a single photograph: Semantic modeling of indoor scenes from a single photo

We present an automatic approach for the semantic modeling of indoor scenes based on a single photograph, instead of relying on depth sensors. Without using handcrafted features, we guide indoor scene modeling with feature maps extracted by fully convolutional networks. Three parallel fully convolutional networks are adopted to generate object instance masks, a depth map, and an edge map of the room layout. Based on these high‐level features, support relationships between indoor objects can be efficiently inferred in a data‐driven manner. Constrained by the support context, a global‐to‐local model matching strategy is followed to retrieve the whole indoor scene. We demonstrate that the proposed method can efficiently retrieve indoor objects including situations where the objects are badly occluded. This approach enables efficient semantic‐based scene editing.

Dr. Inventor, Promoting Scientific Creativity by Utilising Web-based Research Objects, FP7

Scientific creativity and innovation represent the beating heart of European growth at a time of rapid technological change. Dr Inventor is built on the vision that technologies have great potential to supplement human ingenuity in science by overcoming the limitations that people suffer in pursuing scientific discovery. It presents an original system that will provide inspiration for scientific creativity by utilising the rich presence of web-based research resources. Dr Inventor will act as a personal research assistant, utilising machine-empowered search and computation to bring researchers extended perspectives for scientific innovation by informing them of a broad spectrum of relevant research concepts and approaches, by assessing the novelty of research ideas, and by offering suggestions of new concepts and workflows with unexpected features for new scientific discovery. Dr Inventor is an attempt to understand the potential of technology in the scientific creative process within current technology limitations. It represents a sound balance between scientific insight into individual scientific creative processes and technical implementation using innovative technologies in information extraction, document summarization, semantics and visual analytics. The outcomes will be integrated into a web-based system that will allow evaluation in a selected research area under real-world settings with carefully designed metrics, benchmarks and baseline for creative performance, leading to tangible measurements on the performance of the technologies in enhancing human creativity and a blueprint for future technologies in computational creativity. Dr Inventor has huge implications for scientific innovation in Europe, as it has the potential to change the way in which scientific research is undertaken. The acceptance of the system by general research communities will open opportunities for many industrial sectors, leading to reinforced leadership of European industry.