Fast Simulation of Skin Sliding

Skin sliding is the phenomenon of the skin moving over underlying layers of fat, muscle and bone. Due to the complex interconnections between these separate layers and their differing elasticity properties, it is difficult to model and expensive to compute. We present a novel method to simulate this phenomenon at real--time by remeshing the surface based on a parameter space resampling. In order to evaluate the surface parametrization, we borrow a technique from structural engineering known as the force density method which solves for an energy minimizing form with a sparse linear system. Our method creates a realistic approximation of skin sliding in real--time, reducing texture distortions in the region of the deformation. In addition it is flexible, simple to use, and can be incorporated into any animation pipeline

Preserving attribute values on simplified meshes by re-sampling detail textures

Many sophisticated solutions have been proposed to reduce the geometric complexity of 3D meshes. A slightly less studied problem is how to preserve attribute detail on simplified meshes (e.g., color, high-frequency shape details, scalar fields, etc.).We present a general approach that is completely independent of the simplification technique adopted to reduce the mesh size. We use resampled textures (rgb, bump, displacement or shade maps) to decouple attribute detail representation from geometry simplification. The original contribution is that preservation is performed after simplification by building a set of triangular texture patches that are then packed into a single texture map. This general solution can be applied to the output of any topology-preserving simplification code and it allows any attribute value defined on the high-resolution mesh to be recovered. Moreover, decoupling shape simplification from detail preservation (and encoding the latter with texture maps) leads to high simplification rates and highly efficient rendering. We also describe an alternative application: the conversion of 3D models with 3D procedural textures (which generally force the use of software renderers) into standard 3D models with 2D bitmap textures

ITEM: Inter-Texture Error Measurement for 3D Meshes

We introduce a simple and innovative method to compare any two texture maps, regardless of their sizes, aspect ratios, or even masks, as long as they are both meant to be mapped onto the same 3D mesh. Our system is based on a zero-distortion 3D mesh unwrapping technique which compares two new adapted texture atlases with the same mask but different texel colors, and whose every texel covers the same area in 3D. Once these adapted atlases are created, we measure their difference with ITEM-RMSE, a slightly modified version of the standard RMSE defined for images. ITEM-RMSE is more meaningful and reliable than RMSE because it only takes into account the texels inside the mask, since they are the only ones that will actually be used during rendering. Our method is not only very useful to compare the space efficiency of different texture atlas generation algorithms, but also to quantify texture loss in compression schemes for multi-resolution textured 3D meshes

Multilevel Solvers for Unstructured Surface Meshes

Parameterization of unstructured surface meshes is of fundamental importance in many applications of digital geometry processing. Such parameterization approaches give rise to large and exceedingly ill-conditioned systems which are difficult or impossible to solve without the use of sophisticated multilevel preconditioning strategies. Since the underlying meshes are very fine to begin with, such multilevel preconditioners require mesh coarsening to build an appropriate hierarchy. In this paper we consider several strategies for the construction of hierarchies using ideas from mesh simplification algorithms used in the computer graphics literature. We introduce two novel hierarchy construction schemes and demonstrate their superior performance when used in conjunction with a multigrid preconditioner

Maintaining authenticity: transferring patina from the real world to the digital to retain narrative value

This research is concerned with utilizing new technologies to harvest existing narrative, symbolic and emotive value for use in a digital environment enabling "emotional durability" (Chapman, 2005) in future design. The projects discussed in this paper have been conducted as part of PhD research by Rosemary Wallin into 'Technology for Sustainable Luxury' at University of the Arts London, and visual effects technology research undertaken by Florian Stephens at University of West London. Jonathan Chapman describes vast consumer waste being "symptomatic of failed relationships" between consumers and the goods they buy, and suggests approaches for designing love, dependency, and even cherishability into products to give them a longer lifespan. 'Failed relationships' might also be observed in the transference of physical objects to their virtual cousins. Consider the throwaway nature of digital photography when compared to the carefully preserved prints in a family album. Apple often use a skeuomorphic (Hobbs, 2012) approach to user interface design, to digitally replicate the patina and 'value' of real objects. However, true transference of physical form and texture presumably occurs when an object is scanned and a virtual 3D model is created. This paper presents three practice-based approaches to storing and transferring patina from an original object, utilizing high resolution scanning, photogrammetry, mobile applications and 3D print technologies. The objective is not merely accuracy, but evocation of the emotive data connecting the digital and physical realm. As the human face holds experience in the lines and wrinkles of the skin, so the surface of an object holds its narrative. From the signs of the craftsman to the bumps and scratches that accumulate over the life of an item over time and generations, marks gather like evidence to be read by a familiar or a trained eye. According to the time and the culture these marks are read within, they will either add to or detract from its value. These marks can be captured via complex 3D modelling and scanning technologies, which allow detailed forms to be recreated as dense 3D wireframe, but the result is often unsatisfying. 3D greyscale surfaces can never fully capture the richness of patina. Authentic surfaces require other qualities such as colour, texture and depth, but there is something else - more difficult to define. Donald A. Norman expands on the idea of emotion and objects by describing three 'levels’ of design "visceral, behavioural and reflective". Visceral is based on "look, feel and sound", behavioural is focused on an object’s use, and reflective is concerned with its message. New technology is commonly seen in terms of its ability to increase efficiency, but this research has longer-term objectives: to repair or even rebuild Chapman's 'broken relationships' and enable ‘emotionally durable' design. The PhD that has formed the context for this paper examines the concept of luxury value, and how and why the value of patina has been replaced by fashion. Luxury goods are aspirational items often emulated in the bulk of mass production. If we are to alter behaviour around consumption, one approach might be to use technology to harvest patina as a way to retain emotional, symbolic and poetic value with a view to maintaining a relationship with the things we buy