Author Topic: Curtain Material causing slow noisy render  (Read 4965 times)

2014-11-05, 21:53:11

omar.essam

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Hi guys,
I'm having an issue with the curtain material, that is slowing rendering and making it more noisy, here are the renders with and without curtains, and the curtain materials settings. render settings are default, lighting is only Peter Guthrie's HDRI.
Please tell me if that is normal, and if it's not what am I doing wrong?! and what is the best way to achieve a good looking+fast rendering curtain, and how if I want to exclude the curtain from HDRI?!
Thanks

2014-11-05, 22:36:58
Reply #1

Coronaut

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Yo mate, please search "AlBEDO" on forum, things will be much clearer after.

2014-11-05, 22:58:27
Reply #2

omar.essam

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Yo mate, please search "AlBEDO" on forum, things will be much clearer after.
Wow.. I'm more confused now :D .. can you give me a little bit more direct information.
But what I understood from all of what I read.. that if something appears "red" in the Albedo element, then it has too high diffuse/reflective white value. is that true?

2014-11-05, 23:13:34
Reply #3

Coronaut

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No no no, yes :D i could be more explanatory here is the link https://forum.corona-renderer.com/index.php/topic,1012.0.html
What i want to say to you, by looking your material, your white is too white...
Basically nothing is white 255.255.255 so if you make bunch of materials in your scene too white it will make your render times higher. So instead using 255 for white you should use 170.170.170 or use 255.255.255 and set level for diffuse to 0.7.
What are you referring is albedo element it is used just so it make it easier for you observing what has high albedo by showing it in red(you can switch to it in corona VFB)
Please read about it as it is well explained in forums.
Also this is just as starting point and one possible reason of your high render times and it is reasonable to expect render times going up when you use translucency, caustics or scene with more complex GI or materials.   

2014-11-05, 23:23:20
Reply #4

omar.essam

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No no no, yes :D i could be more explanatory here is the link https://forum.corona-renderer.com/index.php/topic,1012.0.html
What i want to say to you, by looking your material, your white is too white...
Basically nothing is white 255.255.255 so if you make bunch of materials in your scene too white it will make your render times higher. So instead using 255 for white you should use 170.170.170 or use 255.255.255 and set level for diffuse to 0.7.
What are you referring is albedo element it is used just so it make it easier for you observing what has high albedo by showing it in red(you can switch to it in corona VFB)
Please read about it as it is well explained in forums.
Also this is just as starting point and one possible reason of your high render times and it is reasonable to expect render times going up when you use translucency, caustics or scene with more complex GI or materials.

Thank you a lot Coronaut, I usually do not use 255,255,255 in my scenes, nor 0,0,0 as black, but sometimes I use 220,220,220 or 200,200,200 but that seems too high for Corona too, so i'll stick with 180,180,180 for a maximum white value, that's one thing I learned.
Actually using Albedo element is so useful, I discovered that the cushions on the bed are too white, and I reduced there value and the "Red" in Albedo has gone and the render time was reduced by 1% (fom 8:23 to 8:19 ), so there IS a change in render time.
Next thing is, as I'm writing this, I brought the curtains back and they are SUPER RED in the Albedo element, so I'll reduce their white value and try again and see what I can get.
Thanks a MILLION Coronaut for directing me towards that Albedo thing :D

2014-11-05, 23:35:41
Reply #5

Coronaut

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2014-11-06, 00:04:30
Reply #6

romullus

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Transparency always comes with a cost. Look how drastically rays/s gets reduced in second render - from 4,5M to 2,8
If you're using bitmap in opacity slot, you should take special care in what format you choosing, as there might be a huge difference in performance: https://forum.corona-renderer.com/index.php/topic,4249.0.html
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2014-11-06, 00:21:21
Reply #7

omar.essam

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Transparency always comes with a cost. Look how drastically rays/s gets reduced in second render - from 4,5M to 2,8
If you're using bitmap in opacity slot, you should take special care in what format you choosing, as there might be a huge difference in performance: https://forum.corona-renderer.com/index.php/topic,4249.0.html
No, I don't use any bitmaps in opacity, only a procedural Falloff, from white to very light grey.. but thanks for this piece of  info :)