Rendered Previews of NK Materials


NK Materials


"NK" files store data about the optical properties of a material, as measured in a lab. They are available from several places on the internet, and store info mostly on various metals, glasses and some other materials.

Indigo, the free, unbiased raytracer, can load - most of - these files as materials. Here I provide a list of the NK data files provided with Indigo, with information on which ones work with the current version, and preview images of the ones that do.

Instructions


The NK files can be found in the .\nkdata\ folder of your Indigo installation. To add such a material to your scene, follow this example, of course substituting the al.nk with the proper filename:

<material>
        <name>Aluminum</name>
        <phong>
                <nk_data>nkdata/al.nk</nk_data>
                <exponent>10000.000</exponent>
        </phong>
</material>

All the optical properties, like IoR, CauchyB coefficient and colour are given by the NK data. Only the glossiness needs to be set, with the exponent variable. Set it to 0 for diffuse or over 10000 for glossy reflection.

To export an NK material from Blender, just name the material to "xxx.nk", the name of the file you want to use, and the exporter will automatically create the proper material in the XML file. See here for a complete Blender/Indigo tutorial.

Technical Notes


The previews use the "building" probe (freely downloadable from http://www.debevec.org) as a HDRI light. I opted for a HDR light as it approximates a real scene more than a fake "studio setup".
To make sure all pictures have the same exposure, linear tonemapping is used with a scale of 250000.
The camera white balance is D65


#
 
7059.nk
Glass 7059
     
DOESN'T WORK      
na.      


 


A
 
Ag.nk
Silver
     
WORKS      
     
Againp0.nk, Againp1.nk, Againp3.nk, Againp6.nk, Againp7.nk, Againp10.nk
Aluminum Gallium Indium Phosphide (0%, 10%, 30%, 60%, 70%, 100% Aluminum)
NONE WORK
 

na.

 

Al2o3.nk
Aluminum Oxyde
Al2o3p.nk
Aluminum Oxyde
Al.nk
Aluminum
 
DOESN'T WORK WORKS WORKS  
na.  
AlasXXXt.nk,
where XXX = 028, 052, 072, 098, 125, 152, 178, 204, 228, 305, 331, 361, 390,
421, 445, 469, 499, 527, 552, 578, 602, 626
Aluminum Arsenide, at T=xxx
ALL WORK

Alas.nk
Aluminum Arsenide
Alcu.nk
Aluminum Copper
   
WORKS DOESN'T WORK    
na.    
Algaas0.nk, Algaas1.nk, Algaas2.nk, Algaas3.nk, Algaas4.nk, Algaas5.nk, Algaas6.nk, Algaas7.nk, Algaas8.nk, Algaas9.nk, Algaas10.nk
Aluminum Gallium Arsenide, (number represents Aluminum concentration/10, ie: 2=20%)
ALL WORK
 

Concentration of Aluminum increases to the right.

Alon.nk
Aluminum Oxynitride
Alsb.nk
Aluminum Antimonide
Alsi.nk
Aluminum Silicon
Alsiti.nk
Aluminum Silicon Titanium
WORKS WORKS DOESN'T WORK DOESN'T WORK
na. na.
arachi.nk Asi.nk
Amorphous Silicon
Au.nk
Gold
 
DOESN'T WORK DOESN'T WORK  
na. na.  



B
 
Baf2.nk
Barium fluoride
Bk7.nk
Glass BK7
Bk7_abs.nk
Glass BK7 Abs
 
DOESN'T WORK WORKS - NOT AS EXPECTED WORKS - NOT AS EXPECTED  
na.  



C
 
Caf2.nk
Calcium Fluoride
Carbam.nk
Amorphous carbon
Ccl4.nk
Hexachoromethane
Cdse.nk
Cadmium Selenide
WORKS - NOT AS EXPECTED DOESN'T WORK DOESN'T WORK WORKS
na. na.
Cdte.nk
Cadmium Telluride
Co.nk
Cobalt bulk
Co_2.nk
Cobalt (Hexagon thin films)
Cor7059.nk
Glass Corning 7059
WORKS DOESN'T WORK WORKS DOESN'T WORK
na. na.
Cosi2-4.nk
Cobalt silicide
Cr3si.nk
Chromium silicide
Cr5si3.nk
Chromium silicide
Cr.nk
Chromium
WORKS WORKS WORKS WORKS
Crsi2el2.nk
Chromium silicide
Cu2o.nk
Cuprous oxide
Cu.nk
Copper
Cuo.nk
Cupric oxide
WORKS WORKS WORKS WORKS



D
 
Diam.nk
Cubic carbon (diamond)
     
WORKS - NOT AS EXPECTED      
     



F
 
Fesi2el1.nk
Iron silicide
Fesi2el2.nk
Iron silicide
Fesi2epi.nk
Iron silicide
 
WORKS WORKS WORKS  
 



G
 
GaasXXXt.nk, where XXX = 031, 41, 60, 81, 103, 126, 150, 175, 199, 224, 249, 273,
297, 320, 344, 367, 391, 415, 443, 465, 488, 515, 546, 579, 603, 634
Gallium Arsenide, at temperature XXX °C.
XXX=100 and 111 do not refer to the temperature, but to the crystalline structure.
WORKS
Gaas100.nk and Gaas111.nk DON'T WORK
Preview: temperature increases from left to right, top to bottom.
The two empty spaces are Gaas100.nk and Gaas111.nk, which don't work.

Gaas.nk
Gallium Arsenide
Gaaso.nk
Gallium Arsenide Oxide
Gaasox.nk
Gallium Arsenide Oxide
Gan01.nk
WORKS WORKS - NOT AS EXPECTED WORKS - NOT AS EXPECTED WORKS
Gan02.nk Gan03.nk Gan60.nk Gan70.nk
DOESN'T WORK DOESN'T WORK DOESN'T WORK DOESN'T WORK
na. na. na. na.
gan-tit.nk Gan-uv.nk Gap100.nk
Gallium Phosphide (100)
Gap.nk
Gallium Phosphide
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.
Gapox.nk Gasb.nk
Gallium Antimonide
Gasbox.nk
Gallium Antimonide Oxide
Ge100.nk
Germanium (100)
WORKS - NOT AS EXPECTED WORKS WORKS - NOT AS EXPECTED DOESN'T WORK
na.
Ge.nk
Germanium
     
WORKS      
     



H
 
H2o.nk
Water
Hfo2.nk
Hafnium oxyde
Hfsi2.nk
Hafnium silicide
Hgcdte0.nk
Iron silicide
WORKS - NOT AS EXPOECTED DOESN'T WORK WORKS WORKS
na. na. na.
Hgcdte2.nk
Iron silicide
Hgcdte3.nk
Iron silicide
   
WORKS WORKS    
na. na.    



I
 
Inas.nk
Iron silicide
Inasox.nk
Iron silicide
Ingaas.nk
Iron silicide
 
DOESN'T WORK WORKS WORKS  
na.  
Ingasb0.nk, Ingasb1.nk, Ingasb3.nk, Ingasb5.nk, Ingasb7.nk, Ingasb9.nk, Ingasb10.nk
Indium Gallium Antimonide (0%, 10%, 30%, 50%, 70%, 90% and 100% Gallium)
NONE WORK
 

na.

Inp.nk
Indium Phosphide
Inpox.nk
Indium Phosphide Oxide
Insb.nk
Indium Antimonide
Insbox.nk
Indium Antimonide Oxide
WORKS WORKS WORKS WORKS
Ir3si5e.nk
Iridium silicide
Ir3si5p.nk
Iridium silicide
Ir.nk
Iridium
Ito2.nk
ITO
WORKS WORKS WORKS DOESN'T WORK
na.



K
 
Kcl.nk
Potassium Chloride
     
WORKS - NOT AS EXPOECTED      
     



L
 
Lasf9.nk
Glass LASF9
Li.nk
Lithium
Lif.nk
Lithium fluoride
 
DOESN'T WORK WORKS WORKS - NOT AS EXPOECTED  
na.  



M
 
Mo.nk
Molybdenum
Mosi2-a.nk
Molybdenum silicide
(parallel to c axis)
Mosi2-b.nk
Molybdenum silicide
(perpendicular to c axis)
 
WORKS WORKS WORKS  
 



N
 
Nbsi-a.nk
Niobium silicide
(parallel to the c-axis)
Nbsi-b.nk
Niobium silicide
(perpendicular to the c axis)
Ni2si.nk
Nickel silicide
Ni3si.nk
Nickel silicide
WORKS WORKS WORKS WORKS
Ni.nk
Nickel
Nisi.nk
Nickel silicide
   
WORKS WORKS    
   



O
 
Os.nk
Osmium
     
WORKS      
     



P
 
P_sias.nk
Polysilicon
P_siud.nk
Polysilicon
Pbs.nk
Lead Sulfide
Pbse.nk
Lead Selenide
DOESN'T WORK DOESN'T WORK WORKS WORKS
   
Pd2si-a.nk
Paladium silicide
(perpendicular to the c-axis)
Pd2si-b.nk
Paladium silicide
(parallel to the c axis)
Pd.nk
Palladium
Pt.nk
Platinum
WORKS WORKS WORKS WORKS



R
 
Resi1-75.nk
Rhenium silicide
     
DOESN'T WORK      
na.

     
Resige0.nk, Resige1.nk, Resige22.nk, Resige39.nk, Resige51.nk, Resige64.nk, Resige75.nk, Resige83.nk, Resige91.nk
Silicon Germanium Alloy relaxed (number represents Germanium content in %)
ALL WORK
  Placed in order from left to right, top to bottom.

Rh.nk
Rhodium
Ringas0.nk
OsmIndium Gallium Arsenide relaxed
(0% Indium)ium
Ringas10.nk
Indium Gallium Arsenide relaxed
(10% Indium)
Ringas20.nk
Indium Gallium Arsenide relaxed
(20% Indium)
WORKS WORKS DOESN'T WORK WORKS
na.
Ringas24.nk
Indium Gallium Arsenide relaxed
(24% Indium)
     
WORKS      
     



S
 
Sf11.nk
Glass SF11
Si3n4.nk
Silicon Nitride
(perpendicular to the c axis)

 

 
WORKS WORKS    
   
Si11ge89.nk, Si20ge80.nk, Si28ge72.nk, Si65ge35.nk, Si85ge15.nk, Si98ge02.nk
Silicon Germanium alloy (numbers = concentrations)
NONE WORK
na.
Si100_2.nk
Crystalline Silicon
(100 orientation)
Si110.nk
Crystalline Silicon
(110 orientation)
Si111.nk
Crystalline Silicon
(111 orientation)
Siam1.nk
Amorphous Silicon 1
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.
Siam2.nk
Amorphous Silicon 2
Sic.nk
Silicon Carbide
Sicr.nk
Crystalline Silicon
Sicrir.nk
WORKS DOESN'T WORK WORKS WORKS
na.
Sicr-t02.nk, Sicr-t10.nk, Sicr-t15.nk, Sicr-t20.nk, Sicr-t25.nk, Sicr-t30.nk, Sicr-t35.nk, Sicr-t40.nk, Sicr-t45.nk
Crystalline silicon (at temperatures T=20, 100, 150, 200, 250, 300, 350, 400, 450)
ALL WORK
In order from left to right, top to bottom.

Sige_ge.nk
Silicon Germanium alloy on Germanium
Sige_gi.nk
Silicon Germanium alloy on Silicon
sin_bf5 Singas0.nk
Indium Gallium Arsenide strained (0% Indium)
DOESN'T WORK DOESN'T WORK DOESN'T WORK DOESN'T WORK
na. na. na. na.
Singas10.nk
Indium Gallium Arsenide strained (10% Indium)
Singas20.nk
Indium Gallium Arsenide strained (20% Indium)
Singas24.nk
Indium Gallium Arsenide strained (24% Indium)
Sio2.nk
Silicon dioxide
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.
Sio2ir.nk Sio.nk
Silicon monoxide
Sion0.nk
Silicon Oxynitride
(10% Nitrogen)
Sion20.nk
Silicon Oxynitride
(20% Nitrogen)
WORKS WORKS DOESN'T WORK DOESN'T WORK
na. na.
Sion40.nk
Silicon Oxynitride
(40% Nitrogen)
Sion60.nk
Silicon Oxynitride
(60% Nitrogen)
Sion80.nk
Silicon Oxynitride
(80% Nitrogen)
Siop.nk
Silicon monoxide 1
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.
Sipoly10.nk, Sipoly20.nk, Sipoly30.nk, Sipoly40.nk, Sipoly50.nk, Sipoly60.nk, Sipoly70.nk, Sipoly80.nk, Sipoly90.nk
Polysilicon 2 (numbers represent concentration in %)
ALL WORK
In order from left to right, top to bottom.

Sipoly.nk
Polysilicon 2
Sipore.nk
Porous silicon
Stsg0.nk Stsg064.nk
WORKS WORKS WORKS WORKS
Stsg123.nk Stsg169.nk Stsg229.nk  
WORKS WORKS WORKS  
 



T
 
Ta.nk
Tantalum
Taox1.nk
Tantalum oxide 1
Taox2.nk
Tantalum oxide 2
Tasi2-a.nk
Tantalum silicide
(perpendicular to c axis)
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.
Tasi2-b.nk
Tantalum silicide
(parallel to c-axis)
Test.nk Thf4.nk
Thorium Fluoride
Ti.nk
Titanium
WORKS DOESN'T WORK WORKS WORKS
na.
Tini.nk
Titanium nitride
Tio2.nk
Titanium oxide 1
Tio2b.nk
Titanium oxide 2
Tisi-a.nk
Titanium silicide
DOESN'T WORK DOESN'T WORK DOESN'T WORK WORKS
na. na. na.



V
 
V.nk
Vandadium
Void.nk Vsi2-a.nk
Vanadium silicide
(perpendicular to c axis)
Vsi2-b.nk
Vanadium silicide
(parallel to c-axis)
WORKS WORKS WORKS WORKS



W
 
W.nk
Tungsten
Wsi2-a.nk
Tungsten silicide
(perpendicular to c axis)
Wsi2-b.nk
Tungsten silicide
(parallel to c-axis)
 
WORKS WORKS WORKS  
 



Y
 
Y2o3.nk
Ytrium oxide
     
WORKS      
     

Z
 
Zncdte0.nk, Zncdte1.nk, Zncdte3.nk, Zncdte5.nk, Zncdte7.nk, Zncdte9.nk, Zncdte10.nk
Zinc Cadmium Telluride (Cadmium content: 0%, 10%, 30%, 50%, 70%, 90%, 100%)
ALL WORK
In order from left to right.

Znscub.nk
Zinc Sulfide (cubic)
Znse.nk
Zinc Selenide
Zr02.nk
Zirconium oxide
Zrsi2.nk
Zirconium silicide
DOESN'T WORK WORKS DOESN'T WORK WORKS
na. na.
Znsete0.nk, Znsete1.nk, Znsete3.nk, Znsete5.nk, Znsete7.nk, Znsete9.nk, Znsete10.nk
Zinc Selenium Telluride (Tellure content: 0%, 10%, 30%, 50%, 70%, 90%, 100%)
ALL WORK
In order from left to right.