Basic lighting
What you'll learn to do
Step 1 : Create and adjust the light
In this tutorial, we'll cover the use of one simple light source : the point light. DAZ has many other kind of lights ( HDRI, spotlights, emissive lights to name a few ), but they'll all follow the rules we'll cover here. In this tutorial : we start simple.
These instructions are for DAZ Studio, but you can use any other software.
In environment options, chose "Scene Only". This will tell DAZ to only render the existing light in the scene.
Create a New Point Light. Voila.
To see your light source in effect, you'll have to either :
Hit render
Turn the IRAY interactive preview mode on ( it renders things in realtime )
If nothing show up when you hit "render" or switch to IRAY interactive preview, your light is likely too weak to light the scene :
Increase your light source's Luminous Flux (Lumen), by keeping adding 0's to it.
Nothing shows up ? 15000
Nothing shows up ? 150000
Nothing shows up ? 1500000
Etc...
Step 2 : Size and power !
Light isn't just about intensity. The size of your light source and naturally, its placement will drastically change the mood and points of interest of your scene. There are a few rules that worked for me and may help you guide your choices :
More intensity = More light on the scene
Bigger light source = Softer shadows
Smaller light source = Harsh shadows
The default point light you created has the shape of a "point". A light that's infinitely small. This explains why the default light you created create very harsh shadows
Now try turning the "light geometry" of your point light to a "Sphere". Notice the way the shadow are now soft and smooth.
Since our light source is now bigger relative to the model it shines on, the shadow becomes softer.
Also, it becomes less directive and you might want to add a little lumens to compensate for its loss in intensity.
If you want to prevent this sphere of light we created from being rendered, turn the "render emitter" parameter off.
The light source is still here, but isn't rendered.
You can also change the size of your light's geometry with the Height and Width parameters.
One single light as a point in the distance.
4000000 lumens.
One single light as a sphere in the distance.
Diameter 400. 8000000 lumens.
Now you can try all the other geometries of your light, change their width and height, intensity, move it around... see what it does and how it affect the mood of your scene.
To broadly sum it up...
Harsh shadows create a dramatic and strong effect to your picture. Softer shadows, on the other end, tell a story of smoothness, fluid and caressing mood. So. You're now able to choose the right lighting for the right intended effect !
All these techniques come from the world of photography and, again, I couldn't thank enough @ryald666 for having shared them with me... and now you.