is it possible to render caustics using path engine

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frank_yifei
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is it possible to render caustics using path engine

Post by frank_yifei » Sat Nov 03, 2018 6:36 am

I tried with latest blender addon to render a glass bottle with water, hoping to get a beautiful caustics effect.
I thought it is a matter of rendering time, but after a long time of rendering with path engine, I only got a noise free result. the glass bottle itself looks the same with bidi render. But the shadow of the bottle is solid and no caustics. I heard caustics can be rendered in path tracing renderer but takes longer time. is it possible to do it in luxcore render's path engine?
Also I tried rough glass, it has caustics and gives same result with bidi engine after longer rendering time.
I dont know it is a feature or a bug. Anyway, I created an issue on github.

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B.Y.O.B.
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Re: is it possible to render caustics using path engine

Post by B.Y.O.B. » Sat Nov 03, 2018 9:22 am

You need an intersectible light source, for example an area light or a sun light. A point or spot light does not work, they are infinitely small (not intersectible by path).
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FarbigeWelt
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Re: is it possible to render caustics using path engine

Post by FarbigeWelt » Sat Nov 03, 2018 5:31 pm

Yes, and it works quite well, see e.g.
viewtopic.php?f=2&t=576&start=40#p7043
As B.Y.O.P. explained, use a light with a certain expense, like area lights or a plane with emitting material. The area should be at least that of your object.
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