Getting caustics under the water

daniel_nieto · Post by **daniel_nieto** » Sun Jun 08, 2008 5:49 am

hi everyone!, the other day kikeonline asked me how to do caustics like this scene:

http://www.indigorenderer.com/joomla/in ... temId=5451

easy, i thought, but when i made the scene and rendered it, well, look what it came up (at the end of the post), it's quite lame, so, how to set up the enviroment to get that top notch caustics i see in that image from manitwo or this scene (http://www.indigorenderer.com/joomla/in ... emId=16099) by smartDen, the last one, i can see there's something like SSS, maybe?

thanks for your responsives!!! we'll apreciate the answer, kikeonline and me, hehehe!

BTW: i have tried everything, MTL, BiDir, Hybrid, and every value settings configuration among these, but nothing worked out!

Kram1032 · Post by **Kram1032** » Sun Jun 08, 2008 5:55 am

under water caustics are quite problematic from seen outside the volume....
If you go under water, you'll see caustics

Above, you need to increase your mncr value... There was a huge topic by CCJ, just about water and effects related to it.... Though, the behaviour of Indigo partly changed so I wonder how much the settings, worked out there, still are efficient....

zsouthboy · Post by **zsouthboy** » Sun Jun 08, 2008 5:59 am

You're getting castics underneath the water just fine - however your light source is so large that they're blurry.

To get sharp caustics, make a tiny light source.

kikeonline · Post by **kikeonline** » Sun Jun 08, 2008 6:10 am

OHHHH so thats the problem!!!

I'm going to try it right now

joegiampaoli · Post by **joegiampaoli** » Sun Jun 08, 2008 6:32 am

sun light or even using an ies spot light will work better, large mesh lights are like diffuse lights, like zsouthboy said, they are there but unprerceptable, think of the type of shadows they would cast.

CTZn · Post by **CTZn** » Sun Jun 08, 2008 10:45 pm

Yeah, think caustics as the distorted image of the light source, wich they are really. If you want lines then you have to start with a point.

BbB · Post by **BbB** » Mon Jun 09, 2008 1:17 am

Also, use simple path or MLT. No BiDir.

Post by **OnoSendai** » Mon Jun 09, 2008 1:24 am

bidir does nice caustics BbB

BbB · Post by **BbB** » Mon Jun 09, 2008 1:29 am

I never managed to get sunlight appear inside a water volume with BiDir, for some reason. Same problem as Bidir not showing sunlight behind windows, I thought...

Post by **OnoSendai** » Mon Jun 09, 2008 1:31 am

Yeah, pretty much the same problem, it's just a very tough sampling problem.

cinema · Post by **cinema** » Mon Jun 09, 2008 10:25 pm

I think that your render is fine tuned, you only have to continue to render and wait few hours until caustics appears....I wait for your updates! Bye bye

CTZn · Post by **CTZn** » Tue Jun 10, 2008 1:53 am

Not quite, cinema, as we stated a smaller light source was needed in order to obtain caustics like exposed in the first link.

You are welcome, though

daniel_nieto · Post by **daniel_nieto** » Tue Jun 10, 2008 1:39 pm

i did what you told me to do guys...

here's what i got

CTZn · Post by **CTZn** » Tue Jun 10, 2008 1:51 pm

water = <normal_smoothing>false</normal_smoothing> with displacement ?

daniel_nieto · Post by **daniel_nieto** » Tue Jun 10, 2008 2:18 pm

jajajaja i think i forgot normal smooth, well, i made this starting out with a plane, then i subdivide and fractalize it "thrice", then i just extrude the faces in Y axis and subsurfed it, but i actually forgot normal smooth... no displacement....indeed