Level Design Sunlight!

[Ordinary soldier]

Hello. I have seen maps that have the sunlight actors inside the world cube, and some which have the sunlights in the skyzone cube!
Which way is the correct way? Why all unreal sources say it must be in world cube, but some maps have it in the skyzone cube, and it is working?
Which way is the correct one?
(For Unreal Engine 2.5)

 

[Murphy]

If it's in the sky zone it's going to shine from any Backdrop in the map.

If it's placed in a zone of the map it's only going to shine from Backdrops in that zone.

 

[PiX]

What Murphy said.

 

[Ordinary soldier]

If it's in the sky zone it's going to shine from any Backdrop in the map.

If it's placed in a zone of the map it's only going to shine from Backdrops in that zone.

I am sorry I don't get it.
Ehm..."any backdrop"?
Example:
So I place sunlight in skyzone , and it will shine through the 6 sides of my world cube? It doesn't make sense, because sunlight should only come as parallel light rays from only one direction?

If I place it in the world cube itself, it will still go "through the backdrop" (like its actualy placed outside the world cube, because this way the engine simulates sunlight coming from infinite distance)

And by backdrop you mean fake backdrop right?

It sounds more like zoning?
If I put sunlight in Skycube it will light any zone in my map? THe "outside"world and the "rooms", no matter if they are zoned with anti-portal?

And if I place sunlight in the world cube itself it will only light the "outside world"?
And what happens if I make the "bottom" of the world cube fake backdrop? Some tutorials say only to mark sides and top as fake backdrop, while others dont mention a thing about the bottom...I am getting more and more confused.
And last but not least, if the "fake backdrop" is making light from outside the world cube pass through, then whas is the purpose of "backdrop" only?

 

[Murphy]

Backdrop means you can see into the void. If no skybox is present in the map this is going to result in these smears where the last frame something was rendered in the void is just going to stay.
Like this:

If a SkyZone is present, instead of having nothing to render there the game shows the view of the skybox through the SkyZoneInfo actor, with the same angle as the player's vision.
I.e. shows the sky.

A surface isn't backdrop. It's a surface. But you can let it "fake backdrop", i.e. act as if it was backdrop, and thus showing the Skybox.


Now for the lights.
A sunlight can't just "shine", that's not how they work. They're not like the lightbulb lights that emit light on their own. It needs visible sky (see above) to shine from. The sky is going to emit the light (in parallel rays, as you noted) from the same angle as the sunlight actor points at the SkyZoneInfo actor.

E.g. your sunlight is pointed west, it's going to hit the map from the east.

To make this work, technically only the eastern side of your "world cube" has to fake backdrop. If you want the sky to show up on the others too you'll have to have them fake backdrop too.
The bottom may not be mentioned because whoever wrote what you were reading assumed players aren't going to see it anyway, e.g. because terrain is going to cover the ground. If you're building a floating space-station where players can look down through glass windows in the floor of the station, you're going to need your world cube's floor fake backdrop too, of course.

But the light is still only going to hit from the angle it's pointed from.

Sunlight actor in the Skybox makes the sky emit its light. Period.
A sunlight placed in the map area itself, not in the skybox, makes the sky emit its light but only into the zone this sunlight resides in!