Lovely to see this thread back again:-))

One point I'd like to make ('cos it confused me for a l-o-o-o-o-o-n-g time) is what "angle start/angle end" actually does. I couldn't get my mind around it at all, until one day the penny dropped (tracked by a spot-light)...

(see Doc's page 10)...

"Angle start" defines the angle at which the light (emanating from the spotlight) is at full brilliance.
"Angle end" defines the angle beyond which there is no light (ie dark).
The bit between those 2 angles is the "fall-off zone" - the light darkens (in the yellow area on P10) as it gets closer to the "Angle end"...

Both of these effects are affected by the distance fall-off...

I have to admit to feeling a total fool after the penny finally dropped, it's so obvious! Isn't it? Well.. err... it wasn't to me:-(((

So I'm posting this to possibly help someone else who has the same blind-spot I suffered from..

Cheers,
Diolma