[vtkusers] How to visualize a dataset in sole color?

[zxbo2004]

Hi all:                                                                                                                  
   I have a dataset, and I use vtkTubeFilter to generate tubes according to this dataset, what I want to do is making all these tubes same
color, so I use  vtkActor->GetProperty->SetColor(), but I find this is useless. So I decide to use color map by using vtkLookuptable, if 
I fill the lookup table by sole color, I can achieve my goal, but the color of tube is in RGB format, so how can I change RGB to HSV?
or is there any other way to solve my sole color problem?
                                                                                                              yours bobofzhang