[vtkusers] graphing multiple scalar components with vtkPolyDataMapper

[Chase Yarbrough]

Hello,

I have a vtkPolyData for which I'd like to keep track of several 
different graphable quantities, one in each component of the polydata's 
scalars.  I have two questions.

1.)  How many components in a polydata's scalars are allocated by 
default?  Can I change the number on the fly, or do I have to replace 
the old scalars with a new vtkDataArray that has the proper number of 
components allocated?

2.)  How do I tell the vtkPolyDataMapper which component to graph?  I 
see that there is a "ColorByArrayComponent" method in vtkMapper, but the 
documentation mentions that "it is better to do this in the lookup table."

Thanks for your help,
Chase Yarbrough