Pile Of Old Rings - Complex IOR Metals

Despot · July 07, 2017, 09:29:03 AM

Just another simple test of Complex IOR metals

Rex · July 07, 2017, 10:33:53 AM

Looking great J! Keep 'em coming

Speedster · July 07, 2017, 02:39:33 PM

KS7 dummy question here! What the heck is a "Complex IOR Metal"? I can't find it anywhere in the material types. Or is it the absolutely mind blowing "Anodized Metal" option, rapidly becoming my favorite new feature!
Bill G

Despot · July 07, 2017, 02:50:49 PM

Quote from: Speedster on July 07, 2017, 02:39:33 PM
KS7 dummy question here! What the heck is a "Complex IOR Metal"? I can't find it anywhere in the material types. Or is it the absolutely mind blowing "Anodized Metal" option, rapidly becoming my favorite new feature!
Bill G

I've copied and pasted this from the 'What's New Guide' :

The Metal material type now includes options for Color and 13 scientifically accurate metal presets
including Aluminum, Brass, Chromium, Copper, Gold, Iron Magnesium, Nickel, Niobium, Platinum, Silver,
Titanium, and Zinc, along with the ability to load Complex IOR files (.ior, .nk, .csv), may be chosen for
custom metal appearances. All metal preset provide the additional ability to add an anodized coating with
control of Film Refractive Index, Film Extinction Coefficient, and Film Thickness. The Anodized settings
are available for all metal presets selected from the Metal Type dropdown. Learn more in the manual on
the Metal material type page.

So instead of controlling the colour of the metal surface using a colour chip, a table of IOR data is used instead. This is much more accurate as metal has a complex reflective curve that makes use of an extinction coefficient (how strongly light is absorbed/reflected? at a given wavelength.

So, in a nutshell, use this if you want super-accurate metals...

I've attached a sample .ior file (Osmium) that you can download and try, and this what the IOR data contained in the file looks like :

1 .5 6.5 120
2.41 9.97
2.33 9.12
2.21 8.37
2.11 7.68
2.02 7.04
2 6.46
2 5.95
2.01 5.51
2.03 5.1
2.05 4.74
2.09 4.41
2.12 4.11
2.15 3.84
2.17 3.59
2.16 3.35
2.19 3.04
2.25 2.77
2.35 2.48
2.49 2.23
2.65 2.01
2.84 1.8
3.096666 1.668333
3.36 1.62
3.57 1.66
3.7 1.75
3.76 1.8
3.78 1.83
3.79 1.81
3.81 1.75
3.88 1.67
3.98 1.6
4.11 1.555
4.26 1.54
4.42125 1.5675
4.58 1.62
4.71375 1.679375
4.84 1.76
4.974999 1.870625
5.1 2.01
5.20125 2.183125
5.28 2.38
5.335001 2.588125
5.36 2.82
5.350625 3.102501
5.3 3.38
5.19625 3.59
5.05 3.78
4.871876 3.991249
4.65 4.18
4.35875 4.326875
4.05 4.4
3.75625 4.334375
3.51 4.21
3.375 4.078125
3.29 3.96
3.22 3.91
3.15 3.88
3.04 3.8425
2.93 3.79
2.84875 3.693125
2.79 3.59
2.7625 3.5125
2.75 3.45
2.7375 3.404375
2.73 3.37
2.72875 3.340625
2.73 3.32
2.73125 3.31
2.73 3.31
2.724375 3.320625
2.71 3.34
2.680625 3.369375
2.64 3.4
2.589375 3.421875
2.53 3.44
2.4625 3.459375
2.39 3.47
2.314375 3.460625
2.24 3.44
2.171875 3.4125
2.11 3.38
2.05625 3.345625
2.01 3.31
1.9725 3.27375
1.94 3.24
1.909375 3.213125
1.88 3.19
1.85125 3.16875
1.82 3.15
1.781875 3.135625
1.74 3.12
1.694375 3.0975
1.65 3.07
1.613125 3.035625
1.58 3
1.549375 2.969375
1.52 2.94
1.489375 2.909375
1.46 2.88
1.434375 2.855
1.41 2.83
1.384375 2.800625
1.36 2.77
1.34 2.74
1.32 2.71
1.294375 2.679375
1.27 2.65
1.254375 2.625
1.24 2.6
1.223125 2.5725
1.2 2.54
1.179875 2.511708
1.162 2.486417
1.145625 2.462917
1.13 2.44
1.111719 2.413437
1.09375 2.38625
1.076406 2.358438
1.06 2.33
1.044844 2.300938
1.03125 2.27125

Speedster · July 08, 2017, 10:08:36 AM

Wow! Thanks so much for the clarification, J!

I had missed the "Color" dropdown, as I did not want to change the color. This is an awesome feature! I tested it on my caddy model, and frankly I'm stunned!

The dev team should rename Color to something more accurate, like "Material Type" or something.

Now the IOR thing raises an interesting question. As we know, how a material looks is totally dependent on the lighting and possible reflected environment. It's also dependent on the monitor quality and calibration. I use a high-end EIZO color calibrated monitor, and I have found I can totally trust what I see.

Your superb examples appear to all share the exact same lighting rig, so the differences in metals is obvious.

But we usually tweak materials to "look" right, but may not be "accurate".

So if you spend a lot of time using IOR metals, to what end if they change with every lighting tweak? How do we know they are truly accurate? Not arguing, just curious as to how IOR would be used in our KeyShot world?

With no intent to highjack your thread, I've attached the caddy rendering. I had carefully worked the HDR to match (as close as possible without a photometer) the color temperature of the backplate I shot at RenderWorld. The "Chromium" looks exactly like the chrome I saw on cars arriving and leaving. Amazing!

Bill G

Josh3D · July 14, 2017, 09:21:39 AM

Love the results John, and thanks for explaining the feature! I'll be making a background theme of all your wonderful shots. If I were you, I'd seriously consider doing some posters of your 'piles' and selling them online

Thanks Bill, we could likely expand on the explanation in the What's New and Manual. The drop-down menu actually says 'Metal Type' next to it.

Magnus Skogsfjord · July 21, 2017, 07:39:38 AM

Ring +2 intelligence for the Vizard?

Perfection as always, John!

Despot · July 25, 2017, 08:27:38 AM

Had no idea I had replies to this thread... I've stopped getting notifications from the KS forum.

QuoteWow! Thanks so much for the clarification, J!

No problem Bill, I see you've made great use of the feature

QuoteI'll be making a background theme of all your wonderful shots. If I were you, I'd seriously consider doing some posters of your 'piles' and selling them online

That sounds amazing Josh, can't wait to see it... I was considering selling prints online, until I found some of my work already for sale

QuoteRing +2 intelligence for the Vizard?

You know I'm crap at cryptic crosswords Magnus... help me out here dude

Seriously though, thanks for the comment, they are always appreciated.

Magnus Skogsfjord · July 26, 2017, 04:05:57 AM

Hah, sorry John.. My nerd-factor gets in the way of the message.

<nerd> It's just a reference to RPG's where you usually may find items with various skill upgrades. So, your class "Vizard" would probably benefit from such a ring.</nerd>