An advanced "extra" trick: If you register for the (free, for evaluation), you gain access to the "Allegro PCB Editor Viewer." This is slightly more powerful than the Physical Viewer, but for 99% of users, the Free Physical Viewer is sufficient.
: Features a redesigned, more intuitive user interface with support for both light and dark canvas modes. Cadence Allegro Free Physical Viewer 17.4 Download Extra