[vtkusers] Help me!

[Li Jun]

Hi!Dear VTKUsers,

    I'm a graduate student. I just downloaded the VTKLibrary from the kitware.com. Now I'm learning to use VTK. However, I don't find enough examples to understand the package. And it is very urgent for me now to use VTK to finish some works recently. let me show you my work 
firstly. My target is to extract the iso-curve from a 2D image with VTK in C++. I heard that VTK's marchingsquare is for this work. Could you tell me in detail how can I implement this work by VTK in C++ or C? If possible, could you provide me with a small piece of example codes in C which would show me the procedure? The work condition is that input is a 2D float image. 

Besides, I do my project in C++ envirenment. And I want to visit vtkPolyData's elements,such as, the points and lines. Could you tell me how I can retrieve the vtkPolyData elements? 	

And is vtkImageData accept my own array data,for instance, a float 1D array? How can I transfer my array data into a vtkImageData object?

At last, how can I draw a vtkPolygon object into an image? 

Thank you very much!

Best regards,

Jun Li