[vtkusers] interpolation

[Gopalakrishnan, Gowri]

hi 

does any one know how to do interpolation between 2 (x,y,z) points. 
I have points from lets say (0,0,0) (100,100,100) at an interval of 5 and
i would like to generate the inbetween points.

I tried to look at spline along the three axis. But I did not know what to
put in the
Evaluate(float t) function. I tried to put some arbitrary numbers and I
noticed that the extra 
points that were generated were copies of my original data as many times as
I put in. For example
if  put Evaluate(0.5). My orginal data gets copied twice. 
Could some one explain how this works?

Basically i have 50 points which gives me the profile of my data and I want
to have 100-150 points between
the end points. 

Regards
Gowri