Do I need to reanalyze tracks to view the 3Band waveform ?

You don't have to reanalyze tracks.

Right-click the track and select [Add New Analysis Data] from a context menu.

Follow the steps below to select [Add New Analysis Data] for the all the tracks of the library.

Click Collection

Click a track list to set the cursor on the track list.

Press [Ctrl+A] to select all tracks.

Right-click and select [Add New Analysis Data] from the context menu.

If the selected track contains a track that already has [3Band] analysis data, the analysis will automatically skip the track.