Abstract: A method for rendering hair particles includes determining a grid with vertices and voxels bounding the hair particles, determining hair densities for the vertices, smoothing the hair densities, solving a distance function to form a distance field in response to the smooth hair densities, wherein a distance function returns zero at a pre-determined hair particle density, determining a surface normal direction for a hair particle in response to the distance field values, determining a hair illumination value in response to a first illumination source, and determining a shading value for the hair particle using the hair illumination value and the surface normal direction for the hair particle.

Abstract: Color coded signals are superimposed upon one another in order to more conveniently understand phenomenon to which the signals relate. A specific application of the technique is non-destructive eddy-current testing of tubes used in devises such as nuclear reactors for detecting anomalies such as pits, through-holes and dents. The signals generated during the eddy tests are displayed as overlapping lissajous transforms which produce distinctive color patterns for each anomaly.

Abstract: A method for presenting seismic data in a multidimensional visualization. Specifically, in the visualization technique of the current invention, seismic data is displayed in a multidimensional plan view utilizing at least four dimensions associated with the seismic data, such as for example, x, y, time/depth and offset. In the method of the invention, a plurality of time or depth windows are defined along a reflector or any other time or depth surface of interest on the prestack data as presented in standard CMP displays. In one embodiment of the invention, for each CMP gather, a window is defined around the data representing the reflector of interest. Passing through each window are individual seismic traces. The window, being defined on the seismic display, is associated with a finite time/depth segment and will contain several offsets. In addition, since each CMP gather has a constant x and y coordinate, the window is associated with specific spatial coordinates.

Abstract: A method of globally analyzing intersections between objects in computer animation includes providing objects represented by meshes, with each of the meshes being formed by a set of vertices, where a set of pairs of vertices defines a set of edges of the mesh. All edges of the meshes are checked to determine if the edges intersect with any of the meshes. An intersection path, formed by the intersection of the meshes, is traced and which vertices that are contained within the intersection path are determined. A polarity of each of the contained vertices is set to indicate that those vertices are contained within the intersection path. The analysis forms the backbone of a collision-response algorithm for unoriented objects such as cloth that is better than previous existing algorithms. The analysis also allows objects to be simulated even when hand-animated elements of the simulation have extreme amounts of interpenetration.

Abstract: A method models a plurality of graphics models by generating a first adaptively sampled distance field for a first model, and generating a second adaptively sampled distance field for a second model. Locations in the first adaptively are sampled distance field to determine a distance value for each location. The second adaptively sampled distance field is sampled at each location to determine a corresponding feature of the second adaptively sampled distance field. Then, each distance value is modified according to the corresponding feature to determine a second distance value for each location.

Abstract: A graphics system and method for displaying lines on a display device. The system may comprise a sample buffer, a rendering unit and a sample-to-pixel calculation unit. The rendering unit may (a) generate a plurality of sample positions in a two-dimensional space, (b) determine a sample normal distance for each of the sample positions with respect to a line defined by the line-draw command, (c) assign sample values to the sample positions based on the sample normal distance of each of the sample positions, and (d) store the sample values in the sample buffer. The sample-to-pixel calculation unit may read sample values from the sample buffer, filter them to determine a pixel value, and transmit the pixel value to the display device. The rendering unit may render the line sample values with a narrower width to pre-compensate for the line-expanding effect of the filtering performed by the sample-to-pixel calculation unit.

Abstract: A method for converts an adaptively sampled distance field of a graphics model to a triangle model, The adaptively sampled distance field includes surface cells storing distance values that have corresponding gradients. A vertex is assigned to a center location of each surface cell. The vertices of neighboring surface cells are connected to form triangles while satisfying a predetermined constraint. Then, each vertex is moved, in a single step, to a new location according to the distance value and corresponding gradient of the vertex to substantially conform the triangles to a surface of the model.

Abstract: A shadow is generated in a virtual three-dimensional space by adjusting a resolution of a 3D model, projecting elements of the 3D model onto a surface in the virtual 3D space, and rendering a shadow having the adjusted resolution of the 3D model on the surface using the projected elements.

Abstract: An apparatus and method for distributing representative images of a plurality of data objects within a database within a partitioned three-dimensional graphical environment is described. According to the apparatus and method an environment is divided into areas bounded by partitions, and groups of representative images are distributed and displayed upon these partitions. In general, distribution of the representative images is achieved by determining weight factors for each partition bounding a given area and determining weight factors for representative images that are to be displayed within the areas upon the partitions and then distributing the images dependent on the comparison of the image weight factors to partition weight factors.

Abstract: Methods and apparatus, including computer program products, implementing techniques for performing envelope-based computer graphics operations on vector objects in an image. An envelope in an image generally contains an original drawing object. The envelope is a manipulable graphic object defining a coordinate remapping that is applied to generate a resulting drawing object for any original drawing object in the envelope. In one embodiment, the envelope has an interior control point that is an anchor point. User manipulation of the interior control point redefines the coordinate remapping. In another embodiment, a precision variable determines how closely an object in the envelope will follow the envelope when the corresponding resulting object is generated. Additional control points can be added to the original contained object if necessary to achieve the required precision before applying the coordinate remapping.

Abstract: Computer-implemented method and apparatus for processing data representing a three-dimensional object model includes generating an image of a modeled object. The modeled object is formed from a number of different components that can be arranged in different positions, and the generated image depicts a change in a position of a first one of the components with respect to a second one of the components.

Abstract: A circuit for providing an overlay in a window on a computer output display including scaling circuitry, storage circuitry for receiving a plurality of lines of source data, input circuitry for loading the storage circuitry in a first prefill mode and in a second low water mark mode, and circuitry for selecting a mode for loading the storage circuitry responsive to the characteristics of the demand for data placed on the storage circuitry.

Abstract: A computer-based method of processing a computer graphics illustration having pieces of artwork includes mapping outlines of the pieces of artwork onto a grid of cells, determining a number of outlines that map to a cell, and identifying a complex region based on the determined number of outlines that map to the cell.

Abstract: Recognition of predetermined critical objects in a graphic display is enhanced by storing a plurality of object descriptions which are segmented into critical objects and background objects in an image database. The critical objects and the background objects are transferred to a computing engine which renders the critical objects and the background objects according to expert user recommendations. The critical objects are rendered separately with acuity enhancements to generate enhanced critical objects to greatly improve the realistic impression of the object in simulators. The background objects and the enhanced critical objects are then transferred into a memory buffer as a graphic image and it is then displayed at a single resolution.

Abstract: According to the present invention, an image processing apparatus, that can effectively generate a polygon model approximating a shape of an object by a plurality of polygon patches, includes: an input portion for inputting three-dimensional data of the object of the input points; a storage portion for storing coordinate values of the input points input by the input portion; an update portion for updating three-dimensional coordinate values of a plurality of lattice points of the polygon model so as to reflect a distribution density of the input points, the lattice points being arranged to form lattices on a two-dimensional plane; and an output portion for outputting, as the polygon patches of the polygon model, the three-dimensional coordinate values of the lattice points updated by the update portion and a relationship of connections between the lattice points in the lattices.

Abstract: A method for generating a palette-based output image from a source image by variably dithering regions of the source image using an associated regional dithering mask. The palletized output image can be a GIF image or a PNG8 image. The dithering mask contains a plurality of dithering levels specifying the degree to which colors in corresponding regions of the source image can be dithered to paint the output image. The dithering mask stores dithering levels for the source image on a per pixel basis. The dithering mask is stored as an alpha channel of the source image. The palletized output file is generated from the source image on a per pixel basis. For each pixel, a target color is calculated by adding an accumulated error from neighboring pixels to the true color of a corresponding pixel in the source image. The output pixel is painted with the closest color to the target color that is available in the output file's color table.

Abstract: A method regularizes a distance field of a graphics model or object. The distance field includes variable scalar values and a set of fixed zero values. The zero values define a boundary or surface of the object. The distance field is evaluated by a cost function, optimized according predetermined parameters, to determine a cost of the distance field. The variable scalar values are then randomly perturbed while holding the zero values fixed. The evaluating, determining, perturbing steps are repeated until the cost is less than a predetermined threshold. The distance field can be in the form of a non-differentiable implicial field. A surface of the graphics model can be textured or stenciled by following streamlines along the gradients of the regularized distance field.

Abstract: This invention presents a method to extract atomic parts of a graphics model using its skeleton. A skeleton is a fully collapsed body of the model, and is obtained through a novel way to contract edges of the model. From the skeleton, atomic parts or features each is a part of the model that is distinctively autonomous from its connected or neighboring body is formed through space sweeping. Next, atomic parts can be connected into a hierarchy depending on the eventual interactive visualization applications. The operation of the method includes the steps of interactively computing, displaying and recording skeleton, atomic parts, and object hierarchies in response to user commands to, for example, modifying skeleton, atomic parts or object hierarchies. Object hierarchies are useful to various applications such as object scene management, view-dependent simplification, mesh-mapping, morphing, and building bounding volume hierarchies.

Abstract: An anisotropic filtering technique includes defining pixel elements in two dimensions and defining at least one object having three dimensional surfaces in a three-dimensional model space and storing texel elements in two dimensions defining a texture map bearing a relationship to the three dimensional surfaces of the at least one object. Each pixel element to be texture mapped is divided into a group of sub-pixel elements and the sub-pixel elements are separately texture mapped. The resultant textures of the sub-pixel elements are averaged to obtain a texture for their respective pixel element.

Abstract: A map simplification system performs dynamic view dependent simplification of relatively large geographic maps.