[vtkusers] how to handle an empty pipeline?

[Langer, Stephen A. (Fed)]

Hi --

What's the right way to handle a pipeline that might at times have no data in it?   I'm connecting to a vtkDataSetMapper,  and if the input stream is empty vtk prints a warning "vtkDataSetSurfaceFilter: Number of cells is zero, no data to process".    I don't create the vtkDataSetSurfaceFilter myself -- it's been inserted into the pipeline by the mapper.  It doesn't do that if the input data is poly data, and if I change the input to poly data, the mapper seems quite happy with the empty pipeline, so it's odd that it complains in one case but not the other.

Is there something that I should do at the pipeline source to tell the pipeline not to run?  Is there a way to suppress just this one warning message?

I'm using vtk 7.1.1 in C++.

Thanks.
 -- Steve