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We present two new techniques for rendering 3D vector fields in scientific visualisation. We also present a new technique called texture splats for rendering these volumes efficiently. >

Techniques for visualizing several climate variables, particularly clouds and wind velocities, are discussed. The techniques are volume rendering, textured contour surfaces, and vector field rendering. The application of these techniques is discussed in the context of a high-definition television (HDTV) animation produced to show global cloud motion during ten simulated days in January. The computational grid is defined by nearly a million grid points-320 evenly spaced longitudes, 160 unevenly spaced latitudes, and 19 unevenly spaced surfaces of constant geopotential. The climate variables at every grid point were output at every hour of simulated time, resulting in 380 MB of data per simulated day. >

The output of a scan-line visible-surface algorithm is a collection of scan-line segments with associated simple shading functions, which together define the shading as a function of a continuous variable along each scan line. A hybrid antialiasing method that uses this information fully is presented. The method extends to the case where an image transform maps the scan lines into slanted lines in the output raster coordinates. Edge-slope information can be used to infer data along extra scan lines to improve antialiasing. Results obtained with the method are given. >

Bump mapping was introduced as a method of rendering realistic shading on bumpy surfaces, without actually rendering a full 3D model of the bumps. Bump mapping works well for parameterized surfaces. The authors interpret the 3D texture as a displacement function to be added to the surface position. >

Starlike surfaces can be defined in spherical coordinates by a function r( theta , phi ) on the unit sphere, which can be expanded in spherical harmonics to give a consequence of smooth approximations to the surface. This method has been used to approximate the solvent-accessible surface of a molecule. The coefficients in the expansion provide a small collection of numbers that characterize the molecular shape. The resulting smooth surfaces can be rendered with random dots or smooth shading. These spherical harmonic surfaces have advantages for modeling overall molecular shape, particularly time-averaged shapes relevant to electrostatic and other intermolecular interactions. >