Physically realistic rendering of light passing through lens - is it possible?

Hi!

I’m a very new in Blender, so, may be my question is naive, but i’m spent 3 evenings digging in the forum and google, but still can’t find a way to render physically realistic lens (which will be able to condense light, for example).
What already done (Blender 2.64, POV-ray 3.7, Cycles):
I have a very simple scene, which looks like that (picture).
As you can see, light beam is perpendicular to the ground. Lens (upper object) are made according to this material http://goo.gl/ZTVp5 for Cycles rendering and as http://goo.gl/r6TtM for POV-ray. Unfortunately, in both cases picture is almost the same - light do not want to be focused via my lens.
Scene file is attached to this message (lens it is a Sphere.001 object)


May be, material parameters are wrong? But for cycles i’m tried exactly the same copy-pasted lens and same material, as in the page http://goo.gl/ZTVp5. Also, all data, what i can dig from the prism example, is put into material for POV-ray.
It seems, that i’m just missing something very easy due to my “newbiness” :slight_smile:

I would be happy, if someone can help.

P.S. Forgot to say, why i need all this physical stuff: i want to make a model of fluorescent microscope lightpath.

Attachments

Lens-cycles.zip (634 KB)

Actually, it seems, that something wrong in the POV-ray script generation by Blender, because POV-ray by itself is able to simulate normal light dispersion (picture 1).
But prism, made inside blender do not work properly. Also, mirrors do not want to work (no reflection on the wall, no color change of passed light, picture 2).
Is it possible to do something with that? Any ideas?
P.S. Scene file in the attachment.

Attachments


Prism2.zip (83.4 KB)

Think in terms of compositing. The “converging light beam” could be a cone, with a specular-only material attached. It’s composited into the shot (using the node-based compositor) with perhaps a “glow” filter attached in the pipeline.

When Hollywood filmed a western, they never built one whit more of “the town” than you could actually see on-film. The interiors were entirely separate sets (with no exteriors). Your purpose is not to “actually physically model” reality, but rather to “imitate the visual consequences of” reality … and to do so in the least-expensive way that you can manage.

“What, visually, tells you that a beam of light is converging?” Well, there’s a cone-shaped brighter area. And, there’s a small bright spot, maybe of different color. All in addition to the base-scene shown in post #1. That is potentially three separate channels of information, each one dealt-with separately and then “mixed-down” (like an audio recording is done these days) to produce the final print. Your eyes instantly accept what they expect to see, and your brain provides a physically-correct explanation for it (having not found, “at a glance,” anything to disprove it …), but this is not how the magician (you…) actually performed the trick. (And the audience neither knows nor cares.)

I’m confused, are you using BI? If that’s the case, you should throw any hope of getting realistic light interaction out of the window. Cycles handles this sort of problem just fine, however. As long as you’re willing to wait for convergence.

Try LuxRender. Should be able to create convergent caustics like you are looking for.

I’m confused, are you using BI? If that’s the case, you should throw any hope of getting realistic light interaction out of the window. Cycles handles this sort of problem just fine, however. As long as you’re willing to wait for convergence.

No, it’s a POV-ray pictures, not BI. Actually, I have a same problem with Cycles, when light do not want to be dispersed.

Try LuxRender. Should be able to create convergent caustics like you are looking for.



I did yesterday late night :slight_smile: Very initial results with 1 meter diamond prism is on picture below.
Useful links for someone, who have a same problem: http://www.luxrender.net, http://goo.gl/uByzn, http://goo.gl/0MrzY and, finally, most important http://goo.gl/GUF6X

So, finally, answer is - LuxRender (as i’m googled, Yafaray also should be ok). Lens, prism, dichroic and a ton of dispersion - on the picture below (sorry for noise). Scene file is attached (if someone inerested - oval-shaped lens has also dichroic effect. Thanks for help!


Attachments

Lux-prism.zip (812 KB)