Abstract: A cel image is rendered by a computer to have a "toon" look that simulates a traditional hand-drawn cartoon cel. The toon appearance of a cel image is characterized by the use of areas selectively colored with a fill, a highlight, or a shadow color. The present invention uses a material shader modified to return a value defining the color applied to each area in the scene being rendered as a function of a predetermined highlight threshold angle, which is compared to the angle of each light ray intersecting surfaces in the image. An edge detection convolution filter is applied to define color lines between the different color areas in the colored image. Contour lines defining the shape of an object and lines on its interior surfaces are determined by applying an edge detection convolution filter to surface normal data for the colored image. Additional smoothstep or gain filters may be applied to improve the contrast of the color lines and contour lines and to thicken the color lines.

Abstract: For use in composing and/or editing a multimedia work that include one or more clips, a technique for indicating an active state of the clip or portion thereof, indicating effects applied to a track or a clip, and indicating a plurality of effects applied to a track or to a clip. At least a portion of the work is graphically represented by one or more timelines on which are disposed one or more clips. An active portion of a clip is indicated by a colored bar that extends under that portion of the clip. Different types of transitions between clips are indicated by using one of different predetermined colors for the colored bar. Effects applied to a track are also represented by color bars that extend above the portion of the track to which the effects apply and are independent of changes to any clip disposed on the track. Predetermined colors are used to indicate the type or class of effect(s) applied. A plurality of effects applied to a clip or to a track are indicated by stacking the colored bars.

Abstract: A three-dimensional graphic object appearing in an animation is deformed to simulate the effects of motion on the object. A user can selectively apply a stretch, yield, or flex deformation effect to the control vertices of the object, to change the shape of the object as a function of any of a linear velocity, angular velocity, linear acceleration, or angular acceleration of the object. Various other parameters for each of these deformation effects can also be selected and set by the user, including a sensitivity to the motion in generating the deformation and a maximum deformation. The flex deformation can selectively be set to either a linear or curved profile, simulating the effect of friction applied by the environment on one or more surfaces of the object. The stretch deformation can selectively be set to either a constant or a free volume to simulate the effect of inertia, causing a body to elongate or shrink in the direction of the movement.

Abstract: A curve projected onto a NURBS surface defines trim regions on the NURBS surface. A plurality of spaced-apart points are defined on the curve and rays are project through the points toward a NURBS surface. Any intersections of the rays with the NURBS surface is mapped into the U,V domain. Corresponding points of adjacent rays are connected to define at least a portion of each trim region on the NURBS surface. Transitions on the NURBS surface between adjacent rays are detected based upon differences in the number of intersections of adjacent rays. The location of each transition is determined to within a selected tolerance by using a binary subdivision of the interval between adjacent rays. The location of such transitions is used to determine how intersections of the rays with the surface at the boundaries of the NURBS surface should be connected. Parity assigned to the rays at each intersection determines the direction in which intersections along the rays are connected.