Sorry I'm over-thinking everything to be too complex, that is why I can't read manuals like you guys do. 

You have one point light entity with a texture name set on the _surface key

Now this one point light is considered a template and will not display light from itself.

But any texture with the name specified as the value in the _surface key will have that point light template applied about 2 units above the surface. You can use the _surface_offset (Maybe not the right formatting) to adjust how far the light template is from the texture.

So you could have 1 point light used to cast light from all of a specific light texture. 

Now that makes sense, I simple prefer more practical answers. 

This will good for plats and trains, and all kind of places where light wouldn't touch otherwise, right? 

As I remember, you place one master light to define all the properties. One of those is the texture name. The others are all the normal light key/value settings. When light.exe runs, it automatically creates a light entity, with the properties you defined (brightness, delay, wait, etc), some number of units away from (in front of, below, above, etc) every surface with the texture you specified.

For surfaces above a certain size (64x64?) it starts adding more lights. This is where I always had problems. The way the surfaces were subdivided seemed erratic and unpredictable. Maybe that has gotten fixed, it's been a long time since I tried it. 

You'll have to go into the editor and decide for yourself where surface lights could be used best.

The example of ericw's site is a good case for it though. Where any place where the small rune texture is used it gives off light.

Delay 2, light 150 was just an example...you could do anything you want. If your originally plan was to place a point light with a high wait value on every instance of a rune texture then _surface lighting makes a great deal of sense!

I haven't played with surface lighting all that much but for when I did it worked quite well. I still like to fine tune values for individual sources however as different room sizes can change how the light is displayed.

You can also make the _surface lights act as spotlights with the _surface_spotlight key and value of 1 

https://drive.google.com/file/d/0BwxYkKdSD855cUlrYVl1Vk14WDg/view?usp=sharing

It feels like it doesn't light everything equally, maybe that is something to expect.

So should it be like lamps, rune icons etc. and not plane surfaces? like in my case I tried to use texture I used for extending platforms. 

I think that has to do with a new surface light being added every 128 units. So if you have large planes you are going to get some subdivisions and not the good Rush kind.

Lamps, and light textures in general are a much more suited option. 

But then again, it only works for maps where every light source from one specific texture is somewhat designed to be same, same range and intensity. Surface lighting would be good for giving this .. "ambient light" feel to some places that doesn't have much real light sources like fires, lamps etc.

You thinking about the same thing? 

What is difference between delay 3 and 4? 

maps where every light source from one specific texture is somewhat designed to be same, same range and intensity.

That's generally how lights should be...consistent so surface lighting could be beneficial here. In terms of ambient light where there are scarce sources of light then I just think of delay 5 lights. 

Oh sorry, I use delay 2 and delay 5 together.. delay 2 would be consistent of course. 

Is it possible to make door call target again, when it closes? For example I'm trying to turn on some lights when door opens, but when it closes it turns off lights. 

this could have saved me so many light ents.., 

So the issue is that the lights are targeted again when the doors close?

If you just want the lights to turn on when the door opens for some initial wow factor then just put a trigger brush in the doorway. 

If you target a light with your doors(only one though) yes, every open and close cycle of the doors will turn the light off/on or on/off(spawnflag set to "start off").

If you give both doors the light as a target nothing will happen. 

testing again... 

Sorry for the confusion.

From what I tested, it seems you'll need to set the door to "toggle", then set up a trigger brush to open the door and turn on the light. Then copy that trigger brush where the player will hit it again. Setting up delays and resets as needed.

BTW, the door and light can have the same name, the trigger brush will activate both.

If I left it up to only the door to trigger the light it only worked for either the open OR close operation. You couldn't get both. 

I don't know. Neither sounds very useful so I've never tried them. 

Thank you, timing will be hard to calculate though.. if only there would be closed event to know exactly when it is actually fully closed.

Func_train have these corner events, but re-creating door to be func_train might not be wise move. Unless it is easy to create func_train behave like doors, also including same sounds like door's have. 

func_train as a door which triggers the light ;)

http://www.quaketastic.com/files/misc/func_train_ex_Newhouse.zip

If you need an explanation let me know. 

More experienced AD mappers, here is questions for you.
How do you use func_train's corner_route, corner_switch and corner_pause, is there any maps already using these a lot? 

now i know why the orange box is called the orange box

there is a pack of developer textures for quake like those in HL2 ?