[vtkusers] 2d/3d math plotter: vtk or opengl ?

[Francesco Montorsi]

Hi all,
    I need a good cross-platform 2d/3d plotter for a math program.
Since I did not find any open-source tool for this, I'm going to write my own ;)

However I'm still unsure whether I should use VTK or directly openGL for such software.
So, I'd like to ask you:

1) does anyone managed to create something like what I'm going to write ?
    I checked VTK FAQ/wiki but I couldn't find anything math-oriented...

2) I'm a VTK newbie. However I used openGL some years ago... which facilities could VTK 
give to me over plain openGL ?

I'm always reluctanct to add a new dependency to my project so I'd like to be sure that 
VTK gives me something important that I need besides "utility classes" like strings, 
arrays, data containers, etc (which I already have using wxWidgets)...

Thanks for any hint !

Francesco Montorsi