question

Sumit Kumar avatar image
Sumit Kumar asked ·

should arnold be calculating SSS if all lights in the scene are hidden?

arnold-stats1001.txt

sss-rendertimetestsimplegeometries.pdf

Arnold Core : [5.1.1.0]
Maya : [Maya2018]

MtoA : [3.0.1]


Hey Guys,

So i was doing a test lately for SSS render time and calculation with some simple geometries.
I have attached a document of that as well, Please go through it, I found out

- SSS is getting calculated even after switching off the lights

- SSS sample-rays is not effecting render time if there is no SSS shader is scene it only dose when we have any SSS shader available in the scene

Here is the section of render stats for the file saying SSS is getting calculated even there is no lights in the scene. i have attached arnold-stats file as well please have a look

"top session self-times by category": [
{
"name": "randomwalk SSS",
"time microseconds": 105491261,
"time percent": 36.290733337402347,
"components": [
{
"name": "pSphereShape1",
"time microseconds": 32832353,
"time percent": 11.29487133026123
},
{
"name": "pCylinderShape1",
"time microseconds": 26255038,
"time percent": 9.032166481018069
},
{
"name": "pConeShape1",
"time microseconds": 24922258,
"time percent": 8.573668479919434
},
{
"name": "pCubeShape1",
"time microseconds": 21481610,
"time percent": 7.390028476715088
}
]
},

renderlightshader
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Max Tarpini avatar image
Max Tarpini answered ·

Should you click 'render' at all if your scene does not have any light ?! :)

That said , situation is something like this. SSS has to walk anyway before getting to the point to evaluate illumination. Once there it will eval to black but it took anyway time to get there. Eventually what are you suggesting that every shaders at init should check for lights ? It's already done by Arnold that warns you about that, some renderers even stop rendering.

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