Manual for ghostlights?

Masterstroke

I'm in need some guidance for ghostlights, for I don't see any of the advertised advantages in my daily usage.
I don't see any decrease in render times at all and the render remains grainy on indoor scenes.
On top of that, I am all confused about the latest set of ghostlights. Which are the latest?
Is that normal arrow suppose to point at the room inside or outside?
Where exactly to set this ghostlight? Can it intersect with the windows?
Should it be inside from the windo?
Should it be outside the room, close to the window?
all I can tell is, that interior scenes are actually getting brighter, but there is no benefit in render times for me.

Elor

I think the latest product built around ghost light is one by @esha:

https://www.daz3d.com/invisi-lights-ghost-lights-and-light-profiles

Unlike ghost lights products by @KindredArts, it does require 4.22 and is based on the new way of creating ghost lights introduced with Daz Studio 4.22 so if you need ghost lights with an older version of Daz Studio, the product by esha will not work.

Esha shared tips and advices on how to use her product but they apply to ghost lights in general too so should answer a couple of your questions (I don't know enough to answer them myself, lighting is still something I struggle with).

Richard Haseltine

Creating a "Ghost Light" - Daz Studio 4.21.1.26+ - Daz 3D Forums  has info on creating ghost lights in more recent  versions of DS. How much they help with render times or convergence will depend on where they are and what else is in the scene - they are most effective when theya re filling in areas that would otherwise receive little direct light.

background

A ghost light is generally used to illuminate a scene without representing any specific light, so for example you could place a large ghost light just below the ceiling of a room and it will illuminate the room.  Although ghost lights are 'invisible' the light they generate is not, so be careful that your ghost light is not reflected in any mirrored surface ( unless you specifically want that effect.)

joanna

Masterstroke said:

all I can tell is, that interior scenes are actually getting brighter, but there is no benefit in render times for me.

Ok, this is a very basic understanding (I'm sure there are people more knowledgeable than me), but there might not be a benefit of render times, and I would not look at ghost lights for that benefit alone (to me, the main benefit is lighting up those pieces of the scene that need more light but I don't want the light to be visible). On one hand, you're making the space brighter, and darker areas render longer, but on the other, you're adding a light which means that another light has to be calculated during rendering, and that adds render time. And you might not be making the space bright enough to see any render time reduction.