Still working away on this, although I did get diverted for 6 weeks or so on shaders.
Thanks to Janbo, I've made a quantum leap in shader understanding (but still novice!) but enough to be able to realize the effect I wanted to achieve for the sentinel scanner.
This effect is about 90% complete now and looks fab. I modeled it on the laser scanner as seen at the start of "aliens".
Original effect:
Adaption:
I wanted to be able to make the light effect be blocked by other objects and using a fan object with 100 vertices which are manipulated after getting the vertex distance. The light can be scaled in all sizes to suit intensity and range/height with correct results. I may increase the vertex count to get more integrity on the beam intersection effect, but it's looking quite nice already if I say so myself