A framework for digital sunken relief generation based on 3D geometric models

Sunken relief is a special art form of sculpture whereby the depicted shapes are sunk into a given surface. This is traditionally created by laboriously carving materials such as stone. Sunken reliefs often utilize the engraved lines or strokes to strengthen the impressions of a 3D presence and to highlight the features which otherwise are unrevealed. In other types of reliefs, smooth surfaces and their shadows convey such information in a coherent manner. Existing methods for relief generation are focused on forming a smooth surface with a shallow depth which provides the presence of 3D figures. Such methods unfortunately do not help the art form of sunken reliefs as they omit the presence of feature lines. We propose a framework to produce sunken reliefs from a known 3D geometry, which transforms the 3D objects into three layers of input to incorporate the contour lines seamlessly with the smooth surfaces. The three input layers take the advantages of the geometric information and the visual cues to assist the relief generation. This framework alters existing techniques in line drawings and relief generation, and then combines them organically for this particular purpose

Development of the pilot whale mud mounds and associated subservice features within the NE Faroe - Shetland basin

In this paper we argue for our NPAR system as an effective 2D alternative to most of NPR research which is focused on frame coherent stylised rendering of 3D models. Our approach gives a highly stylised look to images without the support of 3D models, and yet they still behave as though animated by drawing, which they are. First, a stylised brush tool is used to freely draw extreme poses of characters. Each character is built up of 2D drawn brush strokes which are manually grouped into layers. Each layer is assigned its place in a drawing hierarchy called a Hierarchical Display Model (HDM). Next, multiple HDMs are created for the same character, each corresponding to a specific view. A collection of HDMs essentially reintroduces some correspondence information to the 2D drawings needed for in-betweening and, in effect, eliminates the need for a true 3D model. Once the models are composed the animator starts by defining keyframes from extreme poses in time. Next, brush stroke trajectories defined by the keyframe HDMs are in-betweened automatically across intermediate frames. Finally, each HDM of each generated in-between frame is traversed and all elements are drawn one on another from back to front. Our techniques support highly rendered styles which are particularly difficult to animate by traditional means including the ‘airbrushed’, scraperboard, watercolour, Gouache, ‘ink-wash’, and the ‘crayon’ styles. We believe our system offers a new fresh perspective on computer aided animation production and associated tools. Keywords:Artist driven, stylised modelling, stylised animation, computer animation, computer-assisted animation, NPR, NPAR

Ridge-Valley Lines Smoothing and Optimizing

When detecting ridge-valley lines on 3D mesh model, estimation of the curvature and curvature derivatives may often yields to squiggly and noisy result, because the estimation is sensitive against unwanted surface noises. We present two algorithms to obtain smooth and noiseless ridge-valley lines. First, we apply an iterative procedure on ridge and valley vertices and their previous and next neighbors on connected feature lines, which leads to smooth lines. Secondly, we propose an algorithm to distinguish noises from meaningful feature lines based on graph theory model. Each separate feature line is considered as an undirected weighted graph which is called as Feature Graph. We can reasonably get rid of most noises and preserve meaningful feature lines through optimizing the minimal spanning tree of each feature graph. ? 2006 Springer-Verlag Berlin/Heidelberg.EI