r - Maximum values for line width (lwd) argument in RGL -

I do not understand why there is a maximum maximum limit for the rgl argument. In RL. Working in the Segment 3D () may not possibly exceed line width 6-8, but this does not seem to be compulsion. Example illustrates:

  requirement (RGL) x = representative (sample (1: 10,50, delegate = t), each = 2) y = representative (sample (1: 10,50) , Rep = T), each = 2) z = representative (sample (1: 10,50, delegate = t), each = 2) z [(1:50) * 2] = 0 d = data.frame (x Segment 3d (D, LW = 2) Segment 3D (D, LWD = 8) Segment 3D (D, LWD = 50)  

P> What is this happening?

This is not really an answer, just a performance of what I get.

  Segment 3D (d, lwd = 8)  

  Segment 3D (d, lwd = 50)