Fake Caustics in EEVEE :)

This is not a feature requesit, its ratther a discovery I would like to share.
Fake caustics are possible in EEVEE, YAY:


This is awesome! I’ll have to give it a try.

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Wow! This is exactly what I was looking for. I have been working with Ice and this did the trick! Thank you! Real Time Fake Caustics! We live in the future!

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I have done it a bit differently.
I love that Cool trick.
I mainly use it for cycles


@Hypersomniac this would be a nice feature to have, certainly artificial and not physically correct, but I assume that it costs little to add giving the possibility to create interesting visual effects :grin:

Has anyone tried this on 2.81? i’m not having so much lunch unfortunately

doesn’t seem like the light path is doing anything TIA

It looks like you’re right. I think it is the Light Path node. Have you reported this?

No i haven’t i didnt know if it was just me lol.

The shadows on 2.81 are on point but there seems to be a a few shading anomolies that got introduced. All my parallax mapping testing seems to have broken as well.

Thank you @DanPool ! i see your report is closed

the original screen shot seems to have more variation in the shadow but it still is better then nothing

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this is using a slightly modified version of the second version posted gives more depth in the “refractions”

i tend to prefer alpha blend as it gives a cleaner render i noticed the tube does have some odd ortifacts however i believe it’s due to having show backface on, i want to see if it does it in 2.8 as well since i don’t remember it doing that but I love that the blender community and devs work on things so quickly

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nice to see that it works again

so i’m not sure if it’s a “bug” per say or something i’m missing … so i was messing with it over the weekend more and noticed that if i used blend theres some odd artifacts from certain angles but over all it looks clean however if i use hash it looks noisy/ the back isnt as pronounced… see attached

also does anyone have some tips for the shadow noise? even with shadow maps at 4k it still is noisy?

it is smoothed out on all fronts more when bumping render samples but going up to 512 to get a clean render seems a bit much and even then there’s still a bit of noise. 512 (24 seconds)

128 (6 seconds)

obviously I know we’re for lack of a better term… “hacking” the system to get these results so it needs more render time to sell it appropriately but if there was a way to get blend alpha to work nicely it would not run into this issue as we would just need to bump shadow samples up and leave the reast

thank you all for your amazing work in the community :slight_smile:

This is not working for me in 2.82. Is it still working?

You’re right. It doesn’t work any more :frowning:

Works in 2.92. Use hashed shadow mode. A great hack, thanks!


The best caustics hack in my life… Lol!!!