This is what were aiming for:
http://imageshack.us/photo/my-images/691...de191.jpg/
But first I'm giving a step by step guidance for simple mansion window with simple Fixed axis billboards.
First I prefer using spot light to aim the direction of the light. When you're done with that, use a single billboard in the middle of the window to be used as the basic angle for other billboards. You better choose the color of the billboard at this point, so you don't have to go change the color of a dozen billboards.
Then start placing the billboards around the window. Try to follow the outlines of the window, but don't follow them too much, because you don't want your billboards looking like a box. I prefer not to use grid at all (symmetry can actually look bad with billboards). I used blue billboards so I can actually see where I'm placing them (so you don't go out of the windows bounds) and I would just have to change the color of blue into 0.26 at a later stage.
When I got done with the placement and rotating of the billboards, I adjusted the length so they wouldn't stop at the same spot (remember to move them accordingly the changes).
Then just change the color to what you want and go see how it turned out. Adjust the placement and colors, try to look at them from every angle and look for any gaps. If you find a gap, try to fix it with just rotating some billboards. I didn't pay too much attention to that in this window...
You can add a halo or another lightblue lightray right to the window so it appears like glowing, experiment with the amount of color it has. I made it a little brighter than the other billboards. This is how my hasted window looks like, not anything fancy but I hope you take your time with the billboards and perhaps use a few more than I did, just make sure you make them darker when you have more, because they stack:
http://imageshack.us/photo/my-images/860...ide06.jpg/
The next trick was used by frictional games in a several places. It is very easy and quick to do, but it can look bad when up close. Perhaps use these for round holes up high in ceilings.
Then just stack halos or lightrays like in the image, preferably the brighter the higher (halos would have actually looked a lot better, but you should get the point from this.
This is how it will look up close in game. I did this real bad, but it might look okay if its up high, out of view.
I will update this thread shortly with one more window step by step (more detailed)
This particular cellar window is very easy to do actually. First I started off with the aim of the spot light with proper gobo.
Then I aimed and colored one billboard to be used as duplicate source. With this window the aiming is quite easy since you can follow the edges of the window.
I duplicated the original billboard and followed the edges with symmetry but still mainly placed the billboards at random. Be sure to rotate the billboards so they cover mostly every angle of view.
On this window I go a simple step further that will actually give a lot more realism to billboards. I set my rotate snap to 1 (unnecessary because you can go without grid if you're steady handed, but it is still quite useful). And start rotating the billboards X and Z so they poke outwards from the windows hole and appear little more spread out. Don't mind my cool paint skillz showing the box that the billboards do.
...continues in next post....
Next I changed the length of the billboards (long at middle, smaller at edges).
Then I created lightray just at the window for some unnecessary glow effect.
In the next picture I painted green lines to indicate my "faults" with the placement of billboards. These small spots with no billboard don't really look that bad, but small things can make a difference (I didn't fix these btw)
At last I finished the lighting and added some particle effects (1fog and 2 light dusts)
Give some feedback (Was this helpful? Was this confusing? Is it well written? Lots of grammar faults? Are my billboards bad? And so on...
I almost forgot to add the map with all the pictures I took, just so you can look closer if something is unclear or something. I can't edit the post anymore so I hope its readable
LINK:
http://www.mediafire.com/?zc79jy6otd7dwcq
And please note that there is no 1 right way of doing billboards. Its all about the artists view