{"id":73,"date":"2019-08-19T16:47:38","date_gmt":"2019-08-19T08:47:38","guid":{"rendered":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/?page_id=73"},"modified":"2019-08-19T16:58:39","modified_gmt":"2019-08-19T08:58:39","slug":"npr","status":"publish","type":"page","link":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/?page_id=73","title":{"rendered":"NPR\u7b46\u89f8\u751f\u6210"},"content":{"rendered":"\n<hr class=\"wp-block-separator\"\/>\n\n\n\n<h1 class=\"wp-block-heading\">Shape-Oriented Brush Stroke Synthesis in Non-Photorealistic Rendering<\/h1>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"http:\/\/163.22.17.152\/cglab\/images\/cur_3_1.jpg\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/images\/cur_3_1.jpg\" alt=\"\"\/><\/a><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><a href=\"http:\/\/163.22.17.152\/cglab\/images\/cur_3_2.jpg\" target=\"_blank\" rel=\"noreferrer noopener\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/images\/cur_3_2.jpg\" alt=\"\"\/><\/a><\/figure>\n\n\n\n<p>Non-photorealistic \nrendering (NPR) has been an important topic in the research field of \nComputer Graphics. Instead of pursuing the photo-realism of images, \nresearchers of NPR focus on the representation of painting style. \nPainting style consists of many different elements, such as brush \nstrokes, coloring, texture, composition, subjectivity, intention, \nexaggerating expression (, i.e. freedom from rigid formalism), and so \non. Among these elements, brush strokes and coloring are the most \nspecific, personal and identifiable characteristics for computer \ngraphics. Therefore, simulation and synthesis methods for brush strokes \nand coloring are one of the mainstreams of NPR research.<\/p>\n\n\n\n<p>According to the types\n of input resources, approaches of NPR can be roughly divided into two \ncategories, image-based NPR and model-based NPR. Image-based NPR \nprocesses two-dimensional images directly by using image-processing \ntechniques mainly. On the other hand, the input data of model-based NPR \nis three-dimensional models of objects and scenes. Based on the \nprinciples of computer graphics including 3D-translation, curvature of \nmodel, lighting and shading, the later synthesizes images with NPR \neffects.<\/p>\n\n\n\n<p>In this paper, by \nutilizing the information that is extracted from the shapes, we propose a\n model-based NPR system to simulate several types of brush strokes on a \nmodified z-buffer.<\/p>\n\n\n\n<h1 class=\"wp-block-heading\">Simulating NPR Watercolor Painting based on the         Lattice Boltzmann Method<\/h1>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/cur_3.files\/image002.gif\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/cur_3.files\/image004.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>Non-Photorealistic  Rendering (NPR) has been an important research topic in the field of Computer Graphics. Instead of highlighting the realism of CG synthesized          images, NPR focus on the representation of the stroke and painter\u2019s style. For the research of NPR watercolor, simulating water diffusion and flow in paper is an important task. <\/p>\n\n\n\n<p>In this paper, we implement a NPR watercolor system. Our scene is composed with 3D models. The special visual effects of watercolor paintings are created by          simulating the color mixing and the different concentration of watercolor. <\/p>\n\n\n\n<p>To achieve the above goal and the \u201cBrush-Washing\u201d effect, the water flow on 2D paper is simulated based on the Lattice Boltzmann Method (LBM). Moreover, the          strokes of watercolor are simulated by utilizing the auxiliary bone structures and the shapes of three-dimensional models. <\/p>\n\n\n\n<p>A stroke consists of multiple pixels. The color on each pixel is calculated by Phong\u2019s reflection model. Therefore, the color on a stroke gradually transits          from pixel to pixel. This approach creates nature and vivid appearances of strokes. In another word, our proposed method creates the tone of strokes automatically based on the 3D information of scene.<\/p>\n\n\n\n<p>As shown in the experiment results, our system synthesizes watercolor NPR animation with interesting and nature color, tone and strokes.<\/p>\n\n\n\n<p>\n        <a target=\"_blank\" href=\"http:\/\/163.22.17.152\/cglab\/data\/movies\/Zing\/demo.avi\" rel=\"noreferrer noopener\">Movie link<\/a><\/p>\n\n\n\n<h1 class=\"wp-block-heading\">Simulating the Oil Painting in an NPR 3D Animation System<\/h1>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/cur_3.files\/image006.gif\" alt=\"\"\/><\/figure>\n\n\n\n<figure class=\"wp-block-image\"><img decoding=\"async\" src=\"http:\/\/163.22.17.152\/cglab\/cur_3.files\/image008.gif\" alt=\"\"\/><\/figure>\n\n\n\n<p>Non-Photorealistic Rendering (NPR) has been an important issue in the field of Computer Graphics. Instead of highlighting the realism of CG synthesized images,          NPR focus on the representation of the stroke and paint style. One of the most important features of Non-Photorealistic Rendering is the exaggeration expression over the subjects of image. Therefore, NPR is suitable to synthesize images that simulate the paint style with the visual effect of strokes. The research issues of NPR can be roughly divided into two types, 2D image-based method and 3D model-based method.<\/p>\n\n\n\n<p>In this paper, we synthesize 3D model-based NPR images and animation with continuous volumetric strokes to simulate the visual effects of oil painting. According to our survey on oil paintings, we conclude that the heap of  pigment and the volumetric property of each single stroke are two of the most important factors in the works of oil painting. According to the distance from the strokes to the edge of the object, we set up the priority of all strokes. Based on the order, through dynamically segmenting the canvas apart, we make the grouping with regional stroke in the object. And then pile strokes in the same group. The information of the thickness of strokes is stored in a Z-buffer-like data structure. The 3D canvas is then rendered based on this information.<\/p>\n\n\n\n<p>Main contribution of this research includes producing the volumetric strokes, and simulating the oil color correctly on the canvas. These goals are achieved by piling up the strokes on the same pixel, and superposing the pigments to simulate the final resulted color on the canvas.<\/p>\n\n\n\n<p>\n        <a target=\"_blank\" href=\"http:\/\/163.22.17.152\/cglab\/data\/movies\/Joster\/demo.html\" rel=\"noreferrer noopener\">Movie link<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Shape-Oriented Brush Stroke Synthesis in Non-Photoreali &hellip; <a href=\"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/?page_id=73\" class=\"more-link\">\u95b1\u8b80\u5168\u6587 <span class=\"screen-reader-text\">NPR\u7b46\u89f8\u751f\u6210<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":3,"featured_media":0,"parent":30,"menu_order":2,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"_links":{"self":[{"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/pages\/73"}],"collection":[{"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=73"}],"version-history":[{"count":4,"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/pages\/73\/revisions"}],"predecessor-version":[{"id":79,"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/pages\/73\/revisions\/79"}],"up":[{"embeddable":true,"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=\/wp\/v2\/pages\/30"}],"wp:attachment":[{"href":"https:\/\/cgda.csie.ncnu.edu.tw\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=73"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}