Plot lines in 3d as cylinders

You're posting in the Software section, so I assume you want to do it using a computer program, but you didn't tell us which one.

Also, how do you mean: plotting lines as cylinders? You mean you want to draw a cylinder of radius r along a line?

 

From the help,

Code (Text):

Cylinder[{{Subscript[x, 1],Subscript[y, 1],Subscript[z, \
1]},{Subscript[x, 2],Subscript[y, 2],Subscript[z, 2]}},r]
represents a cylinder of radius r around the line from (Subscript[x, \
1],Subscript[y, 1],Subscript[z, 1]) to (Subscript[x, 2],Subscript[y, \
2],Subscript[z, 2]).

So you could simply use that command.

How you would convert to that from your raw data depends on the version of Mathematica (I suspect you are using 6.0+) and the precise format of the text file.