In the last few years several systems have been written for aiding in the conventional two-dimensional animation process. The main purpose of these systems has been to let the computer produce ...missing drawings based on extreme drawings produced by animators. While there has been some success and a great deal of optimism, the promise of higher output and quality using a computer has not been realized. The transition from simple drawings optimized for use on the computer to the complicated and detailed drawings of quality conventional animation has been much harder than expected. The principle difficulty is that the animators drawings are really two dimensional projections of three dimensional characters as visualized in the animators head, hence information is lost, ie. one leg obscures another. The problem of making a program infer the original object from its projections is akin to extremely difficult artificial intelligence problems. Efforts to overcome this by drawing skeletons or increasing the number of overlays require more manual intervention thereby offsetting the gains of using the computer. One way to analyze an approach is to determine the average time required of an artist or operator at all stages of animation for every frame. A second problem not generally recognized is that a production animation system requires the management of hundreds of thousands of drawings, hence data base management techniques not normally found in experimental animation systems.
High quality computer animation Catmull, Edwin E.
Proceedings of the 4th annual conference on Computer graphics and interactive techniques,
07/1977
Conference Proceeding
Educating the digital artist for the entertainment industry (panel) Swartz, Charles S.; Catmull, Edwin E.; King, Robin ...
International Conference on Computer Graphics and Interactive Techniques: Proceedings of the 24th annual conference on Computer graphics and interactive techniques,
08/1997
Conference Proceeding
The problems of computer-assisted animation Catmull, Edwin
International Conference on Computer Graphics and Interactive Techniques: Proceedings of the 5th annual conference on Computer graphics and interactive techniques; 23-25 Aug. 1978,
08/1978
Conference Proceeding
Open access
In the last few years several systems have been written for aiding in the conventional two-dimensional animation process. The main purpose of these systems has been to let the computer produce ...missing drawings based on extreme drawings produced by animators. While there has been some success and a great deal of optimism, the promise of higher output and quality using a computer has not been realized. The transition from simple drawings optimized for use on the computer to the complicated and detailed drawings of quality conventional animation has been much harder than expected. The principle difficulty is that the animators drawings are really two dimensional projections of three dimensional characters as visualized in the animators head, hence information is lost, ie. one leg obscures another. The problem of making a program infer the original object from its projections is akin to extremely difficult artificial intelligence problems. Efforts to overcome this by drawing skeletons or increasing the number of overlays require more manual intervention thereby offsetting the gains of using the computer. One way to analyze an approach is to determine the average time required of an artist or operator at all stages of animation for every frame. A second problem not generally recognized is that a production animation system requires the management of hundreds of thousands of drawings, hence data base management techniques not normally found in experimental animation systems.
An algorithm is presented that solves the visible surface problem at each pixel independently. This allows motion blur and depth of field blurring to be integrated into the algorithm. It also allows ...parallel processing. The algorithm works on large numbers of polygons. An analytic Gaussian filter is used. The filter can be elongated or scaled differently for each polygon to adjust for its speed or distance from the focal plane. This is achieved by shrinking or scaling the polygon prior to solving the hidden surface problem so that blurring is correctly presented when objects obscure each other.
A hidden-surface algorithm with anti-aliasing Catmull, Edwin
Proceedings of the 5th annual conference on Computer graphics and interactive techniques,
08/1978
Conference Proceeding
In recent years we have gained understanding about aliasing in computer generated pictures and about methods for reducing the symptoms of aliasing. The chief symptoms are staircasing along edges and ...objects that pop on and off in time. The method for reducing these symptoms is to filter the image before sampling at the display resolution. One filter that is easy to understand and that works quite effectively is equivalent to integrating the visible intensities over the area that the pixel covers. There have been several implementations of this method - mostly unpublished - however most algorithms break down when the data for the pixel is complicated. Unfortunately, as the quality of displays and the complexity of pictures increase, the small errors that can occur in a single pixel become quite noticeable. A correct solution for this filter requires a hidden-surface algorithm at each pixel! If the data at the pixel is presented as a depth-ordered list of polygons then the average visible intensity can be found using a polygon clipper in a way similar to that employed by two known hidden-surface algorithms. All of the polygons in a pixel are clipped against some front unclipped edge into two lists of polygons. The algorithm is recursively entered with each new list and halts when the front polygon is clipped on all sides, thereby obscuring the polygons behind. The area weighted colors are then returned as the value to be added to the other pieces in the pixel.
With the recent developments in fast hidden surface algorithms and a method for smooth shading of half-tone pictures, it has become feasible to generate useful movies with the computer. This paper ...describes a system used to make computer generated movies. It also explains the methods used to attempt to solve the problems of object representation, object manipulation, concurrent motion, and ease of specifying motion. The system was first used to make a movie of a hand that lasts for little more than a minute.
In recent years we have gained understanding about aliasing in computer generated pictures and about methods for reducing the symptoms of aliasing. The chief symptoms are staircasing along edges and ...objects that pop on and off in time. The method for reducing these symptoms is to filter the image before sampling at the display resolution. One filter that is easy to understand and that works quite effectively is equivalent to integrating the visible intensities over the area that the pixel covers. There have been several implementations of this method - mostly unpublished - however most algorithms break down when the data for the pixel is complicated. Unfortunately, as the quality of displays and the complexity of pictures increase, the small errors that can occur in a single pixel become quite noticeable. A correct solution for this filter requires a hidden-surface algorithm at each pixel! If the data at the pixel is presented as a depth-ordered list of polygons then the average visible intensity can be found using a polygon clipper in a way similar to that employed by two known hidden-surface algorithms. All of the polygons in a pixel are clipped against some front unclipped edge into two lists of polygons. The algorithm is recursively entered with each new list and halts when the front polygon is clipped on all sides, thereby obscuring the polygons behind. The area weighted colors are then returned as the value to be added to the other pieces in the pixel.
