Gouraud shading

About: Gouraud shading is a research topic. Over the lifetime, 170 publications have been published within this topic receiving 7915 citations.

Illumination for computer generated pictures

Abstract: The quality of computer generated images of three-dimensional scenes depends on the shading technique used to paint the objects on the cathode-ray tube screen. The shading algorithm itself depends in part on the method for modeling the object, which also determines the hidden surface algorithm. The various methods of object modeling, shading, and hidden surface removal are thus strongly interconnected. Several shading techniques corresponding to different methods of object modeling and the related hidden surface algorithms are presented here. Human visual perception and the fundamental laws of optics are considered in the development of a shading rule that provides better quality and increased realism in generated images.

Continuous Shading of Curved Surfaces

Abstract: A procedure for computing shaded pictures of curved surfaces is presented. The surface is approximated by small polygons in order to solve easily the hidden-parts problem, but the shading of each polygon is computed so that discontinuities of shade are eliminated across the surface and a smooth appearance is obtained. In order to achieve speed efficiency, the technique developed by Watkins is used which makes possible a hardware implementation of this algorithm.

Shade trees

Abstract: Shading is an important part of computer imagery, but shaders have been based on fixed models to which all surfaces must conform. As computer imagery becomes more sophisticated, surfaces have more complex shading characteristics and thus require a less rigid shading model. This paper presents a flexible tree-structured shading model that can represent a wide range of shading characteristics. The model provides an easy means for specifying complex shading characteristics. It is also efficient because it can tailor the shading calculations to each type of surface.

Curved PN triangles

Abstract: To improve the visual quality of existing triangle-based art in realtime entertainment, such as computer games, we propose replacing flat triangles with curved patches and higher-order normal variation. At the hardware level, based only on the three vertices and three vertex normals of a given flat triangle, we substitute the geometry of a three-sided cubic Bezier patch for the triangle’s flat geometry, and a quadratically varying normal for Gouraud shading. These curved point-normal triangles, or PN triangles, require minimal or no change to existing authoring tools and hardware designs while providing a smoother, though not necessarily everywhere tangent continuous, silhouette and more organic shapes. CR Categories: I.3.5 [surface representation, splines]: I.3.6— graphics data structures

Illumination for computer-generated images.

Abstract: : This report describes a new model for the shading of computer- generated images of objects in general and of polygonally described free-form curved surfaces in particular. The shading function is determined by a linear interpolation of the curvature of the surface. It takes into consideration the physical properties of the materials of which the surfaces are made. By applying the fundamental laws of optics, highlights due to the specular reflection of the light are simulated, and other existing shading problems are overcome. This results in computer-generated images of increased realism. A large number of sample pictures are provided to give a pictorial comparison of the new shading process with past methods. Finally, pictures of simple real solids, such as cylinders, spheres and cones, are compared with those generated by the computer.