Timeseries many Files Data

I have many vti time files which I load with the help of XMLImageDataReader and then I use the ImageDataGeometryFilter to get Polydata Output. My Idea was that I store the different files as Polydata like that:

polyData0= imageDataGeometryFilter->GetOutput()
polyData1= imageDataGeometryFilter->GetOutput()
and so on… if I directly map the Output as follows:
I get an Image. But if I try to put the Polydata in the mapper like this
I get no Image.
The reason why I want to do that is to queue the Polydata and load them into the mapper/renderer so that I do not have any big loading time.

I hope my text is somehow understandable!

Thank you in advance!