The Tube filter is a filter that generates a tube around each input line. The tubes are made up of triangle strips and rotate around the tube with the rotation of the line normals. (If no normals are present, they are computed automatically.) The radius of the tube can be set to vary with scalar or vector value. If the radius varies with scalar value the radius is linearly adjusted. If the radius varies with vector value, a mass flux preserving variation is used. The number of sides for the tube also can be specified. You can also specify which of the sides are visible. This is useful for generating interesting striping effects. Other options include the ability to cap the tube and generate texture coordinates. Texture coordinates can be used with an associated texture map to create interesting effects such as marking the tube with stripes corresponding to length or time.