[R] persp, add lines/highlights

[jjorgensen@fastmail.fm]

Hello R-sters,

I'm trying to add several lines to a response surface that I've plotted
using persp().  I've tried lines() using the "trans3d" function but I've
been unsuccessful in getting it to work (R v2.0.1).  Essentially, I'm
trying to highlight one or more of the surface wireframe lines in a
bolder (or different) color.  Any tips from those of you who have some
experience with this would be greatly appreciated.  [Would it be easier
using wireframe() in library(lattice) instead?]

And, any suggestions on how to add text outside of the persp() plot next
to the highlighted line would be much appreciated.

Thanks,

Jeff Jorgensen