[rivoli]

yep. it's coming.

[Thomas An.]

The only caveat I see is that we do not have a real-life reference of this particular glass. It is possible that the particular geometry might generate a stronger caustic if it was real.

Based on the latest experiment I am quite confident on the technique illustrated in this thread because it is 100% legal based on Maxwell behavior.

In the course of time I will try to perform some real life comparisons:

[rivoli]

The only caveat I see is that we do not have a real-life reference of this particular glass. It is possible that the particular geometry might generate a stronger caustic if it was real.

yes, true. i just rendered a glass which is not that far away from the one you posted as reference.
both hybrid's and mihai's method don't have big caustics problems in this case:



hybrid's one.



mihai's one

edit:
last one before going to sleep:



good night.

[tom]

but the inner reflections of the first one seems better anyway...

[Kabe]

Rivoli, you are constantly referring to the "hybrid's one" as opposed to the "Mihais's one".

If you are referring to Thomas An.'s setup, then I would appreciate if you name it so. If you refer to a different one, then please specify where people can find it.

This is a complicated topic for most readers anyway. There's no good reason to complicate it further by coining new terms without reference or definition.

If this leaves someone like me in the dark, who both followed the discussion and really know what it's about, I'm wondering how the vast majority of people read this, who don't know much about Snell's Law and it's implications.

Just a thought. Hope it helps.

Kabe

[tom]

Kabe you're right, but this ain't a brandnew topic and there's no other way to tell things.
We can't add words to terminology by ourselves easily.
These guys made a great contribution and already drew and rendered tons of diagrams and tests.
There's no way to refine it again and again for a newcomer.
Since, there's no guarantee here to try to tell everyone everything.
If you want to understand what is happening, unfortunately you have to read more.

[Hervé]

Thanks for your help...

[Kabe]

Kabe you're right, but this ain't a brandnew topic and there's no other way to tell things.

I absolutely disagree, because there is a simple way:

It's called linking.

If you introduce a new term into a thread, just set a link what you are refering to. Is that too much to ask?

There's no way to refine it again and again for a newcomer.
Since, there's no guarantee here to try to tell everyone everything.
If you want to understand what is happening, unfortunately you have to read more.

I have read the original thread a while ago, and I do understand refraction relatively well. However, I'm partly lost what they are talking about now, because "hybrid's setup" is not defined in this thread afaik.

My point was that you should at least refer to the definitions of the terms you are using, if you are taking over another thread with new terminology.

Thomas An. has demonstrated a very clear and well though setup. and it get's literally buried under and mixed up with different concepts here.

This is a guarantee that something that was clear at the beginning - even for a newcomer - is going to become a mess just because some guys are just using some mumbo jumbo language that doesn't describe anything in the context of this thread.

Kabe

[Hervé]

well shot Kabe...

[Mihai]

Yeah, I think rivoli it's best if you just say Thomas method ok I just simply verified what he already rendered himself and following the logic and his previous tests with the membranes it's clear that his method works.

If you cut away the glass where the water meets (this is what you call hybrid method here), you get incorrect caustics and reflections (too bright) because they don't take into account the glass, this is why you see more caustics in the hybrid glass ones, which might look prettier but they are incorrect. If you want to get stronger caustics/reflections make the color of the wine slightly brighter.

I'm wondering if the best way to test the accuracy is to make a default glass and render it with mental ray using the physically correct l_glass shaders. There you have to set up 3 surfaces but according to the author, visually, you get correct refractions and caustics.

What do you think? Should we use something like that as a reference, instead of a photo?

Hervé, there's really not much to the model, just follow Thomas diagram and make sure the liquid is enclosed by the glass, that's all.

[Hervé]

well Shot Mihai...

[Thomas An.]

Hi everyone,

By "Hybrid-ND" setup, I am refering to the method where three surfaces are used (one for glass, one for liquid body, one for liquid surface) and the ND of liquid is a hybrid between glass and water.
http://www.maxwellrender.com/forum/view ... =ior#23540

The "hybrid-ND" setup is different than the ThomasAn method.

[Thomas An.]

Here it is time to get a little more serious.

I have setup an experiment scene in my basement. All dimensions of that setup are being measured (including location of camera and the emitters) and a 3d model is being built.

The glass is being modelled down to the millimiter.

When it is done, then we can use this scene (I will upload it here along with the photos) to do some serious comparizons with reality instead of just fiddling with imaginary situations.

Stay tuned.

[Hervé]

First, is there a special reason for seting up everything in your basement... is it because you want a totally dark room...?

You are very right about comparing reality and 3D, this way, we'll know where to go... bang... straight to the wall... of the basement...

depending on how big is your glass, I think millimeters might not be enough... at that point (at least with what you showed, one lousy mm can make difference... No? (please explain..) I mean you all talk about infinitisimal stuff...

[Thomas An.]

First, is there a special reason for seting up everything in your basement... is it because you want a totally dark room...?

You are very right about comparing reality and 3D, this way, we'll know where to go... bang... straight to the wall... of the basement...

depending on how big is your glass, I think millimeters might not be enough... at that point (at least with what you showed, one lousy mm can make difference... No? (please explain..) I mean you all talk about infinitisimal stuff...

The setup is in a small room in the basement because the shape of the room is very simple and the location of the overhead emitter is very convenient and there are no other light sources to contribute to the caustic. (the scene will have a yellow tint, because of the yellow paint on the walls, but it doesn't matter because we are not really looking to replicate the colors)

When I say "to the millimeter" it means I intent to make the replica quite accurate (for both the room and the objects).