We present alternative ways of looking at vector fields that complement existing flow visualization methods. These techniques are based on bump mapping and are simple, easy to compute and fast to render. For example, in one of the techniques a surface from the vector field is extracted and the directions of the vector values on the surface are normalized and used as surface normals. The shading of the surface provides directional information. By manipulating the position and color of light sources, different regions with particular vector directions can be highlighted or hidden allowing direction based selection. Since the technique simply uses the directions of the vector as surface normals to bump the surface, it can also be used on irregularly sampled flow fields as well as for visualizing flow directions on curved surfaces. The magnitudes of the vector values can be optionally mapped to color.
Direction = normal, light source on right (109k)
Direction = normal, left & right lights (116k)
color = magnitude, normal = direction, front & back lights (42k)
color = magnitude, normal = surface normal + direction, front & back lights (43k)
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Magnitude = color (88k)
hue = direction, bump height = magnitude (63k)