Generally I’d use special kinds of lights or luminous surfaces for the majority of what you describe.
[laura plobi] “- On some projects, I need to have lights that are placed along a curve, or on the edges of an object. In that case, I use a cloner to put them automatically. Is there a way around that then?”
I’d say it depends on what you’re after. Do these need to be point lights or are you trying to emulate a long neon or flourescent bulb? If the former, yes I’d use a cloner, if the latter I might create geometry and use a luminous surface with GI if I need detail or use an area light with an Object/Spline area shape (samples might need to be increased).
[laura plobi] “- On some projects, I am creating halogens, led strips or lasers. Each of them may contain 10 to 50 light sources along lines/curves depending on their length, and there are several of those.”
For halogens I’d recommend looking into IES lights for the actual lighting. Then for the visible portion of the light I’d use geometry with a luminous material. No need for GI, the light will illuminate the scene and the geometry is there just to look like a light. For an LED strip I’d use an area light that is roughly the size/shape of the strip and then use geometry with a luminous material. For a laser I’d probably use a parallel spot light with its visibility turned on.
In each of those cases I’d use a single light to achieve the result.
[laura plobi] “- And I also imagine that if I was doing all this “by hand” (rather than automatically with a cloner, which is like a function in the end), I might end up having the same problem of memory space for the rendering, wouldn’t I?”
Yup! Just find ways to avoid using so many lights. I’d also add that since geometry can be instanced you have the option of enabling GI, creating a luminous material, applying it to a sphere (or any ‘light’ shape) and cloning that with render instances enabled. Global Illumination will slow down renders as well but possibly less than using thousands of lights 🙂
Also keep in mind that there are several different components of light. You might get away with creating very few diffuse lights to represent a more complex set of lights and then using luminous geometry to create the desired visibility and reflections.
Darby Edelen