A test of caustics with a photon lamp, and my first post to WIP.
Very realistic ! :o
yeah very realistic
Nice job, and alot can be learned from this simple little masterpiece…
I only started blender in december, so I’m wondering about some of these terms…
-Photon Lamps? How do i create them, and what effect due they cause?
-Caustics? I’ve seen some caustics done of glass like objects, but how did it benefit your ring?
I think that the lamp added those color reflections to the floor, and the Caustics caused the reflection in the ring itself, but couldn’t raymirroring have solved that?
So, set me on the right path here, im eager to learn 
Live Well, Blend Well.
The photon lamp is a feature of Yafray.
To create one, first go to Render Buttons.
Then under the big Render button, click the drop down that says “Blender Internal” and pick “Yafray” instead.
Add a lamp, and now the Photon lamp is available in the list of lamps.
Photon lamps make only caustics (the patterns of light reflecting or refracting from a curved surface). A photon lamp won’t light up anything unless the light was bent or reflected.
The caustics benefitted the ring by making the gold colored reflection on the floor within the ring and in front on the ring. (Just like you thought)
All the reflections in the ring are a result of the ray tracing that Yafray does on anything that is reflective.
More information is in the Blender documentation. See the “Beyond Blender” section:
http://download.blender.org/documentation/htmlI/
Looks pretty good. 
I would like to know if the mesh double sided?
In what direction are the normals pointing?
In Blender this ring mesh is double sided.
The normals are pointing away from the interior of the ring material: the normals of the ouside point out, and the normals of the inside point in.
With normals displayed, it looks like a hairy ring:
I noticed that from Blender, Yafray’s photon lamp does not use the double sided setting, like how Blender’s Subsuf is not affected by it.
The normals are important when using the photon lamp: having a double sided mesh isn’t enough to have the back side of a mesh make caustics.
Didn’t you have some problems
getting this to work at first?
If so what was the problem
and how did you fix it?
Yes, I did have problems at first.
I had made a scene similar to this one in Blender, and I saw that it was missing caustics, so I tried to just switch the render engine to Yafray and add a photon lamp, but that did not work.
So I looked back at the sample Yafray scenes that come with Blender, and I looked more at the Blender documentation.
Then I started over with the simplest scene I could think of: a plane, tube, spot lamp, and photon lamp. This did not work either, but I was sure that it should, so I looked if anyone had done it already. I found others had done what I was trying, so I was encouraged.
I tried playing with a cube based shape, something like one of the sample Yafray scenes. I played with transparency as well as mirror, since I remembered reading on the Web that the transparancy settings are crucial to realistic reflections. It sounded crazy, but I did it anyways.
I finally I got caustics.
After thinking about it, I realized a difference was that a tube has all its normals pointing outside, so that must have been why the inside was not being illuminated by photons.
The other thing I found was that Yafray won’t make photons reflect off of a material unless it’s Index of Refraction (IOR) is set to greater than one. That was the crucial transparency setting.
I remade a ring mesh out of a spun circle,
lit it, and
added some cloud textures for more realism. (I also found Yafray does not support all Blender textures.)
Sounds like the start of a tutorial…
Really urge you to finish that tut ^_^. Yafray is a mystery to me, but I’m just a wannabe on the other hand. Haven’t even gotten through the whole manual yet.
Looks really nice. GW
There is now a tutorial “Simple Gold Ring with Caustics Tutorial v1.0.0” online at
http://www.geocities.com/sound_man_dave/caustics.htm
At the moment there are no pictures, but the steps are given in detail.
This is my first tutorial ever, so don’t expect perfection.
Post any comments about it in this thread.
YafRay.org need mini tutorials like this for helping users to start with YafRay. We are trying to gather all documentation that we can.
If you want, we can put it in our documentation wiki. And I encourage other YafRay users to help to the cause 
and send to us tutorials, tips, and all that could be useful for newbies.
Luis.
Feel free to put the tutorial in the wiki.
What do you think of the first version of the tutorial?
The tutorial has been updated, now it’s 1.1.0.
http://www.geocities.com/sound_man_dave/caustics.htm
I had written some of it from memory, but I found I did not remember it all. 
That’s great, now please add the elven letters on it
That’s a great tutorial, coderdave, thumbs up!
I’ll try putting the Elven letters on it. I haven’t done much texture maping images yet, so it will be good practice.
Here’s a ring made by following the tutorial.
It looks more sparkley, but the floor texture is not as good.
Pictures have been added to the tutorial.
Now it’s “Simple Gold Ring with Caustics Tutorial v1.2.0”
http://www.geocities.com/sound_man_dave/caustics.htm
Please post any comments here.
I love this tut. It really helped me, mainly cause i’ve been wanting to use yfray to make cars and such but have been hesitant to touch it. Thank you for taking the time to post this.