Vray caustics won't work

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Old 08 August 2013   #1
Vray caustics won't work

Hi, i can't get a grip on setting up proper caustics so i followed a simple caustics tutorial and this is the result i get.



As you may notice, I don't get any caustics reflected on the plane. I've checked the material and lighting settings concerning reflection and refraction and everything seems to be in order. He has included a download link to the scene in the description. I used max 2013 and vray 2.40.03.

Does the uploaded scene give you the same results? What seems to be the issue?

Thank you in advance.

Last edited by pkay : 08 August 2013 at 06:21 PM.
 
Old 08 August 2013   #2
Hi!

Well, I can see some beautiful caustics on the plane. Maybe just increase their intensity?
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TD / 3D Artist at Brink Helsinki
 
Old 08 August 2013   #3
I think he means the on under water, make sure you have refractive caustics turned on, you are definitely getting reflective caustics.
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The Z-Axis
 
Old 08 August 2013   #4
Yeah, sorry for being a bit unspecific. I meant the plane below the water plane. Both the water and the grey vrayplane below are set to generate and receive caustics. You may download the scene and see yourself. I'm starting to get a bit frustrated as this seems to happen in other cases when spotlight is involved.
 
Old 08 August 2013   #5
Quote:
Originally Posted by darthviper107
I think he means the on under water, make sure you have refractive caustics turned on, you are definitely getting reflective caustics.


Yes, reflective caustics are on by default;refractive caustics are not.
 
Old 08 August 2013   #6
Vray caustics are tough. So much easier in mental ray. Make sure your light source is a point instead of a plane, if it is a plane. That seems to make all the difference, but even then (for me) it's hours and hours of tweaking values.
 
Old 08 August 2013   #7
Yeah, sorry for being unspecific. The grey vray plane below the water plane does not receive nor generate any caustics even though I've checked all the settings. The water plane (material) is definitely set to reflect and refract caustics.

Is it maybe because the scene is from vray 1.5? Either way, has anyone tried to download and render the scene, just so I can determine whether or not it is a problem on my side?

Thank you very much!

*double post:<

Last edited by pkay : 08 August 2013 at 03:49 PM.
 
Old 08 August 2013   #8
That's strange... I can't get the refraction caustics to show either, from that scene. 3ds max 2014 & vray 2.40.03.
__________________
TD / 3D Artist at Brink Helsinki
 
Old 08 August 2013   #9
Thanks for testing ebee. It seems that the spotlight technique does not work anymore in vray. Is there any workaround in achieving the same supposed result displayed in the tutorial with an other type of light or technique? I know this is easy in mentalray, but I'd like to know how to do this in vray too.
 
Old 08 August 2013   #10
Quote:
Originally Posted by pkay
Thanks for testing ebee. It seems that the spotlight technique does not work anymore in vray. Is there any workaround in achieving the same supposed result displayed in the tutorial with an other type of light or technique? I know this is easy in mentalray, but I'd like to know how to do this in vray too.



I just tested the spotlight and it does still work. It's a pain but it works. Maybe you can post your scene file?
 
Old 08 August 2013   #11
Diffus3d, i included the link 3 posts above.

I followed the tutorial and it didn't work. Then i just tried rendering the completed scene included in the rar (CausticsTrick-Final-01.max) and got the same result. ebee seems to be having the same issue.

Maybe it's a material issue. Either way i'm furious D:.
 
Old 08 August 2013   #12
Quote:
Originally Posted by pkay
Diffus3d, i included the link 3 posts above.

I followed the tutorial and it didn't work. Then i just tried rendering the completed scene included in the rar (CausticsTrick-Final-01.max) and got the same result. ebee seems to be having the same issue.

Maybe it's a material issue. Either way i'm furious D:.
\

Apologies, I missed the link before. I've had many furious moments with vray caustics myself. I'll try to send a file when I get home tonight around 8.

AJ
 
Old 08 August 2013   #13
Thanks, really appreciated.
 
Old 08 August 2013   #14
Ok this was weird, and I don't know *why* this wasn't working. But I was able to get it to work.

The key was to put a shell on the water plane. Which I know, makes no sense. I've seen scenes made by Chaosgroup that didn't have a shell on the water plane, but there you have it.

I just turned up the caustics receive on the ground plane a bit (in Vray properties for the vray plane) and there they were. I didn't tweak them to make them look great, just get them working. I even thought.. "hey is the material 2 sided?" Yup, it was.

Maybe has to do with fog? The search distance in GI settings was 5cm, maybe that was too little and since they caustic photons never made it to the ground through the water because it was great than 5cm. Might be worth experimenting there. (I can do it this weekend, off to my other job right now.)

Here the link: http://www.diffus3d.com/Outbox/CausticsTrick-AJ.rar

But I have to agree with the above people, something isn't right there. Maybe Vlado will peek in this thread later...

Last edited by Diffus3d : 08 August 2013 at 03:50 AM.
 
Old 08 August 2013   #15
Thanks a lot. I guess, for the time being, I'll just stick to mentalray when it comes to caustics.
 
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