The ChipViewer tool provides a graphical view of the fitting report. With this tool you can examine inputs and outputs, macrocell details, equations, and pin assignments. You can examine both pre-fitting and post-fitting results.
The pre-fitting examination looks at the contents of the .ngd file, the design netlist. In this view you can get basic I/O information and make pin assignments that you can pin-lock. You can also modify the contents of your .ucf file.
The post-fitting examination looks at the contents of the .vm6 file, the fitting result. Here you can examine final results, including:
Inputs and outputs
Connections between macrocells
Details of macrocells
Equations by macrocell
Power and slew rate settings