[vtkusers] How to handle node ID and element ID in visualizing FEA model?

[Li, Guosong (G.)]

I am trying to visualize FEA model using VTK.

In the example Cube.cxx, the points are defined with vtkPoints 
and cells are defined with vtkCellArray. 

Then, both of them are used to create cube (vtkPolyData).
In this example, point coordinates are stored sequentially 
with ID from 0 to 8. The connectivity of each cell is defined
by those IDs (from 0 to 8).

But in real application, such as FEA model, each node has 
a unique ID and not continuously fron 0 to N. 

How to store those node coordinates while keep node ID information?
How to store conectivity information (specific nodel IDs) for each cell?

Thanks for your help.

Guosong Li