3D Line textures and the visualization of confidence in Architecture

technical reportThis work introduces a technique for interactive walkthroughs of non-photorealistically rendered (NPR) scenes using 3D line primitives to define architectural features of the model, as well as indicate textural qualities. Line primitives are not typically used in this manner in favor of texture mapping techniques which can encapsulate a great deal of information in a single texture map, and take advantage of GPU optimizations for accelerated rendering. However, texture mapped images may not maintain the visual quality or aesthetic appeal that is possible when using 3D lines to simulate NPR scenes such as hand-drawn illustrations or architectural renderings. In addition, line textures can be modi ed interactively, for instance changing the sketchy quality of the lines, and can be exported as vectors to allow the automatic generation of illustrations and further modi cation in vector-based graphics programs. The technique introduced here extracts feature edges from a model, and using these edges, generates a reduced set of line textures which indicate material properties while maintaining interactive frame rates. A clipping algorithm is presented to enable 3D lines to reside only in the interior of the 3D model without exposing the underlying triangulated mesh. The resulting system produces interactive illustrations with high visual quality that are free from animation artifacts

Enhancing perceived depth in images via artistic matting

Figure 1: Left image features are generally perceived to lie in the image plane. Features of artistically matted image on the right are generally perceived to be non-coplanar and located behind the image plane. We present a simple tutorial for the addition of artistic mattes to digital images for the purpose of enhancing the three-dimensional effect of the image. We show that artistic mattes add visual cues to an image enhancing the sense of depth in the image. We also report the results from two perception studies on matte color preferences and depth estimates in matted versus non-matted images. 1 Artistic Tradition and Image Perception Images of three-dimensional scenes rarely convey the rich sense of depth and geometric complexity apparent when observing the real world. One reason for this is that under almost all viewing conditions

Towards mapping the field of Non-Photorealistic Rendering

Figure 1: The first two images document high and low tide. A comparison between the first two images has a high cognitive overload. However, as shown in hand made example in the last image, mapping the difference between the two images to a easily distinguishable image feature such as multiple tide lines, color-coded by time of day provides the viewer with a much easier notion of tide levels in a single image. Source photographs c○2008 Erik Rasmussen

Investigating studio-based learning in a course on game design

Jobs in the computing field demand communication and teamwork skills in addition to programming skills. Focus at the undergraduate level needs to be shifted towards developing these collaborative skills to enable a more smooth transition into employment in industry. The University of Victoria is in its second year of offering a course on game design. In the first offering, new activities were introduced to address issues identified by recent studies on university graduates entering industry. We focused on integrating cooperative learning, group orientation, and peer review activities into the game design process. The course attracted students across multiple disciplines, and an analysis indicated increased student interest in pursuing a computer science degree. Unfortunately, the same pre- and post-surveys suggested that our collaborative activities may have resulted in a decrease in student interest regarding course work and in pursuing studies in game design. In this paper we report on how we used a studio-based pedagogical approach to restructure the peer review activities in our course. In our previous offering, students received peer feedback only on their final game presentation. In our latest offering, we integrated peer review activities into every step of the game development process, allowing students to refine their ideas while progressing through a game project. A quantitative analysis informs us that our refined peer review activities were successful in increasing student presentation confidence, sense of community, and excitement towards their course projects

Color2gray: Salience-preserving color removal

Figure 1: A color image (Left) often reveals important visual details missing from a luminance-only image (Middle). Our Color2Gray algorithm (Right) maps visible color changes to grayscale changes. Image: Impressionist Sunrise by Claude Monet, courtesy of Artcyclopedia.com. Visually important image features often disappear when color images are converted to grayscale. The algorithm introduced here reduces such losses by attempting to preserve the salient features of the color image. The Color2Gray algorithm is a 3-step process: 1) convert RGB inputs to a perceptually uniform CIE L ∗ a ∗ b ∗ color space, 2) use chrominance and luminance differences to create grayscale target differences between nearby image pixels, and 3) solve an optimization problem designed to selectively modulate the grayscale representation as a function of the chroma variation of the source image. The Color2Gray results offer viewers salient information missing from previous grayscale image creation methods