I have no idea what inspired me to make the lightning, but it had something to do with env_beam. Anyway, I had successfully made a random bolt of lightning every 20 seconds. Added sound, make it more realistic. My friend, who I am teaching to map, told me I should make it more random - so I added 3 more bolts and changed the times. Now, it can happen either seconds apart or 20 seconds apart. Sometimes they overlap. Also, the water kills you if you're in it when the lightning strikes.
Have fun with it. The RMF/MAP is included so you can model after me, and add it to your maps... What are you waiting for? Add some atmosphere to your map!
some possible ideas to tweak the effect:
-make the beams thicker
-add more colors to the beams, 255 255 255 looks unatural
-place steam or mist sprites all over the ground, rendered invisible, and make them appear where the bolts hit. (might be a little entity banging, but i think it's doable..
-same as above, have a bright pointlight pulse on at where the bolt strikes, to simulate a flash, though you are going to run into the "too-many-lightstyles-on-face" error if you use too many.
-same as above, have env_spark, gibs, even breakable ground parts where the strikes hit. Add a breakable tree to add a really cool effect.
-try to capture a lighting strike in the screenshot so people can have a good preview of what the map is right away.
There are tons of ways you could tweak this. I would LOVE to see a mini compo based on lighting1
Very nice proof of concept! 5 stars for a electrifying example map!
=)