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philpappas

Instancing Lights

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Instancing lights isn't the same as instancing geometry. Lights add extra complexity to the scene not through polygon density, but through the extra sampling required to anti-alias directly visible lights, cast shadows, anti-alias bright specular reflections, etc. It's unlikely that you actually need 10,000 lights in your scene. Instead, consider having 10,000 instanced objects with an emissive shader applied, and then if you need actual light cast into your scene, just cast it using a handful of invisible area lights or something similar.

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Not an expert, but consider using a proper renderer as well if you have to manage specific scenes with lots of lights.

Maybe some are better at managing instanced lights than others ?

It seems that Renderman made improvement on that thanks to R&D from Pixar during the production of Coco. And V-Ray uses specific algorithms to improve render times when multiple lights are used ("adaptive lights").

https://www.fxguide.com/fxfeatured/rendermans-visuals-for-coco/

https://www.chaosgroup.com/blog/understanding-adaptive-lights

Not sure these are "better" than Mantra, nor if they are availables on Houdini (eg. seems that functionalities of renderman differs from Katana version for example, compared to Maya or Houdini ones).

Hope this helps a bit if you want to stick to lights instancing...

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A trick that works is deleting all but 1% or so of your points, and only use those points for the actual instanced lights. For the rest of them you can copy spheres onto, and apply an emission shader. It will look like all the lights are contributing to the look.

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On 9/26/2019 at 7:37 PM, philpappas said:

rendering 10.000 instanced lights takes forever. Instancing is supposed to make this happen, no? am i over the threshold or is there another way im not seeing?

light_instancing.hip

Maybe late to this topic, but as they already noted (I can confirm from my direct experience), Renderman 23 has no issue rendering thousands of lights, That's the way to go if you really need that big number of real lights.

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