Abstract: Objects are modeled and rendered using multiple surfaces to provide attributes used in rendering. In some embodiments, a reference surface for an object is defined, e.g., using conventional modeling techniques. One or more auxiliary surfaces are associated with portions of the reference surface. Some of the surface attributes (e.g., color, surface normal, texture, lighting) are associated with the reference surface, while other attributes (e.g., transparency) are associated with the cards. To render an image, a ray associated with a pixel is traced to its intersection with the reference surface and to its intersection with one of the auxiliary surfaces. The attributes associated with the reference surface are determined based on the intersection point of the ray with the reference surface, and the attributes associated with the auxiliary surface are determined based on the intersection point of the ray with the auxiliary surface.

Abstract: Shadows are rendered automatically with a hand-painted appearance. The shadow region is divided into a core and a penumbra. A core perturbation zone is defined between the core and penumbra and a penumbra perturbation zone is defined between the penumbra and an unshadowed region. Within each perturbation zone, a texture is applied to each pixel to map the pixel as being inside or outside the core or penumbra boundary, thereby defining a displaced core boundary and a displaced penumbra boundary. The displaced boundaries can be non-linear and discontinuous. When shadows are rendered using the displaced boundaries, a hand-painted appearance can result. An additional texture can be applied in the penumbra to further enhance the painted appearance.

Abstract: A computer system comprises a memory configured to store a geometric description of an object, wherein the memory is configured to store a first set of parameters associated with a first artistic look, and wherein the memory is configured to store a second set of parameters associated with a second artistic look, and a processor coupled to the memory, wherein the processor is configured to determine a first set of rendered data in response to the first set of parameters and to the geometric description of the object, wherein the processor is configured to determine a second set of rendered data in response to the second set of parameters and to the geometric description of the object, and wherein the processor is configured to determine a visual representation for the object in response to the first set of rendered data and in response to the second set of rendered data.

Abstract: Shadows are rendered automatically with a hand-painted appearance. The shadow region is divided into a core and a penumbra. A core perturbation zone is defined between the core and penumbra and a penumbra perturbation zone is defined between the penumbra and an unshadowed region. Within each perturbation zone, a texture is applied to each pixel to map the pixel as being inside or outside the core or penumbra boundary, thereby defining a displaced core boundary and a displaced penumbra boundary. The displaced boundaries can be non-linear and discontinuous. When shadows are rendered using the displaced boundaries, a hand-painted appearance can result. An additional texture can be applied in the penumbra to further enhance the painted appearance.

Abstract: Objects are modeled and rendered using multiple surfaces to provide attributes used in rendering. In some embodiments, a reference surface for an object is defined, e.g., using conventional modeling techniques. One or more auxiliary surfaces are associated with portions of the reference surface. Some of the surface attributes (e.g., color, surface normal, texture, lighting) are associated with the reference surface, while other attributes (e.g., transparency) are associated with the cards. To render an image, a ray associated with a pixel is traced to its intersection with the reference surface and to its intersection with one of the auxiliary surfaces. The attributes associated with the reference surface are determined based on the intersection point of the ray with the reference surface, and the attributes associated with the auxiliary surface are determined based on the intersection point of the ray with the auxiliary surface.

Abstract: A surface normal map of an object can be interactively modified to create brushstroke-like textures. In one embodiment, surface normal components along the x, y, and z axes (in object coordinate space) are mapped onto red, green, and blue color components. The object's surface is displayed in an editing interface (e.g., a painting program) with colors indicating the surface normals. The user can then modify the surface normals to achieve a desired look for the object. The modified surface normals are stored with the object-model data and are used in rendering the object, helping to create a painted appearance.

Abstract: A computer system comprises a memory configured to store a geometric description of an object, wherein the memory is configured to store a first set of parameters associated with a first artistic look, and wherein the memory is configured to store a second set of parameters associated with a second artistic look, and a processor coupled to the memory, wherein the processor is configured to determine a first set of rendered data in response to the first set of parameters and to the geometric description of the object, wherein the processor is configured to determine a second set of rendered data in response to the second set of parameters and to the geometric description of the object, and wherein the processor is configured to determine a visual representation for the object in response to the first set of rendered data and in response to the second set of rendered data.