How do I make a light that is one color for a few seconds, then it changes to another color, and so on until it loops back to the first color? Is it possible? I have these large billboard ads in my level that change between textures, and it looks wierd when the ad emits white light and then changes to an orange ad that still emits white light.

You can "turn" off and on light entities. So (not looking at GTKradiant at the moment), you can set a sequence with trigger entities and delay. I believe there is a "style" that allows for slow on-off lighting effect, so maybe you can time it so one light is shown while the other is off.

Now how the feck do I do that?

I can't look at Radiant at the moment either, but...
http://www.richdiesal.map-craft.com/tutorials/en220lsn1.html

Probably set 'style' for each light to '2', and use the K hotkey to set color. You'll have to set some trigger mechanism...like so:

Figure out the period of whichever style you use. You'll have to work out some way to trigger each light on and off (to make it start off, set the 'start_off' spawnflag). Probably get half the period and trigger each light in turn- aha. A circle of target_relays with a 'wait' => '<0.5*period>' that have a target of 1) the next relay, 2) the last light (that's on, so it gets turned off) and 3) the next light (to turn it on).

SUMARRY (Easy explaination):

Say you want the lights to go red->blue->green->red. Put 3 light entities in the same place with the style=>2 key, and also have the blue and green lights start_off.

3 target_relays with a wait of half the period of the pulse:
R1 goes to redlight, bluelight, and R2
R2 goes to bluelight, greenlight, and R3
R3 goes to greenlight, redlight, and R1

When the player spawns, have that trigger a trigger_once that in turn triggers the first target_relay.

Or something like that. Echoman can probably correct me- like I said, I just was figuring this out as I was typing it, and have no means to test.

Hope this helps!

Thanks! I'll give it a try when I can. BTW, can I have a link to RichDiesel's main tutorial page?

[EDIT: Never mind, I forgot about changing the URL... :o]

Or, you could always make a simple script that's constantly run.

Just have however many lights you want, script_targetname's individual to each one and then "use" them to switch them on and off within the script. The timings in scripting are much easier than in radiant.

Richdiesal has had some new scripting tutorials put in recently, they're great for learning the basics (which is enough to easily make this work).