Spotlight Lighting Devices, by default, have hard edged beams. You might want to soften that for visualization, or run the barrel, You have two choices. First, you might create a gobo texture or your own like this:
Of course when editing this gobo in a photo editor, you can have varying degrees of softness. Your shutter cuts will still be hard edged, unless you create shutter cuts with custom gobos.
Another option is to use a Vectorworks Light Object. In the illustration below, the light on the left object has equal values for the Beam and Spread (Field). The right object has different vales creating a soft beam.
There is a Vectorworks Light Object inside every Spotlight Lighting Device, you can also modify those values, but that does modify all of your symbols.