This command is part of the On-The-Fly family of commands. Use this family of commands to build your own On-The-Fly OpenGL based primitives that get added to your scene. It must be called within the
<viz>.startLayer and
<viz>.endLayer commands. This will set the width of a line while creating an On-The-Fly object.
viz.startLayer(viz.LINES)
viz.lineWidth(4)
viz.vertex(0,0,0)
viz.vertex(0,1,0)
viz.endLayer()