Here is a example to view analog.
Load project "dac.vtakprj" in samples/vpi folder.
(This is 1bit sigma-delta converter project).

Double click to filt_out1makes analog-waveform as below.
Double click again to dismiss analog waveform.

Analog waveform parameters can be variable by right click. and Analog Parameter...

Then parameter dialog box will appear.
Set appropriate values.
To update the view, dismiss the analog waveform and, double-click will make updated analog waveform.

Right click "filt_out1" signal. ,and set view as Analog with unsigned.