[vtkusers] transparent cells in an unstructured grid

[Jens G.]

Hi VTK users

I have an 3D dataset of a turbulent fluid in a channel represented as an 
unstructured grid. The average velocity at each cell is saved as its 
cell-data.

Now I would like to set all cells 100% transparent, which have a lower 
velocity than x. That way I want to be able to see into the 3D-dataset and 
only get visulised the important regions.

Does anybody has an idea how to do that with vtk?

	Greetings
		Jens