Cadence uses a download manager called "Spectre." You will need to install the Spectre client to fetch the large ISO file.
The viewer supports basic SKILL scripting. Save this simple script as sizeit.il : Cadence Allegro Free Physical Viewer 17.4 Download Extra
: Provides advanced controls for layer visibility and color assignments to simplify the review of high-density designs. Download and Installation Cadence uses a download manager called "Spectre
If you have a capture netlist (from OrCAD or Allegro Design Entry HDL), you can load it into the viewer. Then, clicking a component in the viewer highlights it in the schematic (and vice versa). This requires the netlist.log file saved alongside the .brd file. Cadence Allegro Free Physical Viewer 17.4 Download Extra