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Material and Light tests.


yog
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I'm assuming that NL are still being jerks about keeping the ban on some of it's more "outspoken" clients, so I thought I would post these tests here where everyone could see them.

 

Just a normal round of tests to try and understand Maxwell’s materials better.

 

Edge Reflection.

Reflection (0) = Black

Reflection (90) = Black to White in 10% steps

ND = 3

Edge_Reflt.jpg

 

Centre Reflection

Reflection (0) = Black to White in 10% steps

Reflection (90) = White

ND = 3

Centre_Reflt.jpg

 

Reflection (0) = Black to White in 10% steps

Reflection (90) = White

ND = 50

Note – The change in ND number makes for a massive change.

Centre_Reflt_ND50.jpg

 

ND Setting

Reflection (0) = Dark red.

Reflection (90) = White

ND = 1.5 to 6.5 in 0.5 steps.

Note – Big changes up till ND-4.5, but very little change afterwards.

ND_1.5_6.5.jpg

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ND Setting

Reflection (0) = Dark red.

Reflection (90) = White

ND = 1.5 to 6.5 in 0.5 steps.

Note – Big changes up till ND-4.5, but very little change afterwards.

ND_1.5_6.5.jpg

 

ND Settings (2)

Reflection (0) = Dark red.

Reflection (90) = White

ND = First is 3, then 10 to 100 in steps of 10.

Note – It’s been said by some members of the A-Team that if you want to boost glancing angle reflections, then ND values of between 50 to 80 should be used, this is often quoted when it is remarked on that AGS glass has particularly poor glancing angle reflections. These results seem to indicate that there is practically no change after ND-20.

ND_10_100.jpg

 

Coatings – Interference Colours

BSDF = Mid red Lambertian, ND-3

Coating = ND-3, the rest = standard settings.

Coating thickness = 100000nm to 50nm (steps 1 = /10, step 2 = /2, repeat)

Note – It’s been said that if you don’t want interference colours (oily effect) with coatings, then the thickness should be set to 1000000nm(1mm). Results tend to show the interference colours are limited to the 1000nm to 50nm range.

Coatings_Meg2Dec.jpg

 

Coating ND’s

BSDF = Mid red Lambertian, ND-3

Coating = ND-3 to 13 in steps of 1

Coating thickness = 100000nm

Other settings = Standard

Note – ND’s for coatings seem to have more effect than ND’s for BSDF’s. However ND’s for coatings are limited to 20, higher numbers are automatically reduced to 20.

Coating_ND_3_13.jpg

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Light Sizes.

The sample scene consists of box rooms 3.0m high and deep and 2.0m wide. All lights have the same emitter material applied.

I wanted to see if the size of emitter had any effect on the amount of light they gave off. The results indicate NO, or negligible.

Light_Sizes.jpg

 

Light Types

Here I wanted to see how emitter shape effected the light given off, and whether light was effected by the number of polygons in the emitter.

Left to right, Emitter-1 was a 50 poly sphere, Emitter-2 was a 6 sided box, Emitter-3 a single poly plane, and Emitter-4 was a 1426 poly model of a semi-recessed light fitting with cowl. Again the same emitter material was applied to each.

Light_Brightness.jpg

 

The most noticeable result is that the single plane poly gives off far more light than the six poly box, even though they have the same plan area. This is surprising as the box has a far greater surface area, and even throws light above and to the sides, unlike the single poly plane.

Likewise the 50 poly sphere gives off a lot more light than the 1426 poly light fitting, although admittedly the light fitting has a cowl to prevent side light spill.

I did initially think that emitted light could be adversely effected by the number of polys in the emitter, but a test using a variety of tessellated planes proves otherwise. So it’s more about emitter shape than physical size or poly count (although I still think the box should output more light than a single poly plane).

 

Light Cowls

The first box contains just a bare 30 poly sphere, the rest contain the same sphere surrounded be chrome material cowls of varying spreads.

It’s interesting to see how the two wider cowls really focus the light onto the floor, and it’s good to see the reflected light patterns on the side wall on the bib cowl sample.

Light_Cowles.jpg

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Good tests--thanks!

 

Funny how during beta/RC all the A-Teamers were so insistent that fresnel was handled perfectly and automatically. Now we have three different parameters to customize it--and no real guidance as to what's physically correct.

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Interesting results with the different emitter shapes. I guess some of it could be attributed to more light being directed up and to the sides with the cube, as opposed to all light directed down with the plane.

 

Incidentally, there are other emitter types that intentionally take emitter size into account.

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