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coccosoids
10-29-2009, 09:42 AM
Hello...
It's that time again! :eek:

I got a render, no post-ops, straight out of the render view which looks like this:

http://img688.imageshack.us/img688/9356/34m.png (http://img688.imageshack.us/i/34m.png/)

Areas of concern:

1. Refraction through glass gets too darkened and steers way away from the impression of realism.
2. The surface-tension film surface where the liquid body comes in contact with the glass body doesn't quite cut the 'photo-hyper-realistic' mustard.
3. Aren't the reflections on the glass supposed create a more stringent impression in the reflective floor?

Please advise.
Render Globals Reflection/Refraction/Shadow limits are: 10/10/10 with Max Trace Depth 10.
Glass Material: No Max Distance, Max Trace Depth 20, Solid, Transparent Shadow...

InfernalDarkness
10-29-2009, 10:58 AM
Before going into the technical MR stuff, I think that rendering with a white environment will never make "realistic glass". You need something for the glass to reflect and refract. Glass takes almost all of its color from the environment; this scene is not a great test for glass.

Generally, the mia_material_x is all you need for decent glass. But without an environment, it will never look right.

Sincrol
10-29-2009, 12:45 PM
make sure the normals are correct. make sure de IOR is correct. use some Caustics. you dont need GI to use caustics and it trully helps adding a punch in the face of realism. just shott some photons and activate Caustics...

and, increase the number of rays in raytracing... i can see that in glassCup the refraction is starting to become black.

coccosoids
10-29-2009, 01:11 PM
http://img202.imageshack.us/img202/3360/33m.png (http://img202.imageshack.us/i/33m.png/)

Before going into the technical MR stuff, I think that rendering with a white environment will never make "realistic glass". You need something for the glass to reflect and refract. Glass takes almost all of its color from the environment; this scene is not a great test for glass.

Generally, the mia_material_x is all you need for decent glass. But without an environment, it will never look right.

Thanks Infernal...
I worked around a few of the nuisances.
Can you... Can I... ask you to comment on the rendering, maybe point out some inconsistencies when overlayed over your interpretation of real life glass?

coccosoids
10-29-2009, 01:13 PM
make sure the normals are correct.

What are 'correct normals' in this case... and by extension - in the case of liquid - glass interaction?

InfernalDarkness
10-29-2009, 10:07 PM
I think your gamma workflow is a bit off, and that's not helping the realism much... Are you using a linear lighting workflow? If not, a quick fix (not the most precise method necessarily) is to go into your Render Settings, Quality tab, at the bottom change your Framebuffer to a .454 Gamma. This will help your lights becoming blown out, a bit.

The reason I bring that up is that on my Acer, which is print-color corrected, the entire scene comes out white. I can only tell there's anything there because when I drag it over to my Viewsonic, which is not printer-corrected, the details start to come out and I believe I'm viewing it how you view it. A happy medium is difficult to find, but this scene needs to be much, much darker and have more contrast.

That said, the Index of Refraction is also a huge factor, and Fresnel falloff. I imagine the Fresnel is fine in this scene.

Standard, clean glass is 1.53 IOR.
Water is 1.33
Beer or wine is somewhere lower, in my experiments. 1.25-ish, depending.


Your normals look good in this scene. I think it's just render settings, shader settings, and then having something to reflect and refract that will make it "realistic" for you.

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