[vtkusers] How to write multiple surfaces into a single STL file?

[An Jiye]

Hi.

I have multiple actors rendered in one window. Each of these actors
represents an isosurface. The surfaces are all extracted from the original
data by setting different values to vtkContourFilter.

How can I save all these surfaces into a single STL file?

Thanks for any suggestion in advance.

An Jiye