We do not have a specific light type for creating a visible light beam in ArieVision, like we do in IRender nXt, but there is still a way to make the light beams visible.
1. Draw the spot light with a visible beam in SketchUp, and change the layer of the light beam itself. Also right click on the lamp and un-check "Hide this Lamp..." in the Edit IRender Lamp..." dialog.
The Beams are in the Layer RPS_Lamp_Beams - which we do not render. If you change the layer to anything else, they will render. Here is a rendering with the lamp beam rendered as well.
2. The beam does not gow much - because in this case the beam angle and field angle were 20 degrees, and the light is pretty much parallel to the beam. So I right clicked on the beam, chose Edit Material, and gave it some Illumination.