Comment 10 for bug 654030

I see, you're at the most advanced level already :-) With several slices for elements. I would indeed recommend to use GEXF as the format can nicely represent intervals. I can give you more details about slices. You have two ways to format your intervals, with DATE or DOUBLE (cf the tutorial), so you can be as precise as double values. If your values represents nanoseconds, that is fine, you don't need to define slices properly.
In the GEXF format, slices is just a set of intervals, you don't need to declare them in advance or something like this.

I created the bug 659017 to enable dynamic when importing time interval column from CSV wizard. That would make possible direct import of time intervals if they are correctly formatted.