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Screens emitting light, and noise

Posted: Tue Dec 09, 2014 12:36 am
by vmedium
Image

What the best workflow is for screens that emit light like a phone?

I currently have a diffuse texture with an emissive black body and an image texture in efficiency. This is behind a specular material. That is working pretty good it's just a little noisy.

I've also turned up the sampling rate ont he texture to 10000. Even with octane max samples at 5000 I still get noise, so this makes me think I'm attacking the problem wrong.

Any best practices around this?

Re: Screens emitting light, and noise

Posted: Tue Dec 09, 2014 2:34 am
by FooZe
Light that goes through specular materials is generally a caustic and is more complex to render.
Your best option is to probably use PMC or turn on "Fake Shadows" in the specular material settings if your not concerned about getting physically accurate caustics.

Re: Screens emitting light, and noise

Posted: Tue Dec 09, 2014 6:08 am
by vmedium
I see, thanks I'll give it a try.

Re: Screens emitting light, and noise

Posted: Tue Dec 09, 2014 5:45 pm
by vmedium
I turned on fake shadows and couldn't see a difference. So i removed the emissive black body altogether.

So now it is just the hdri octane sky, and a simple plane, next to the phone, just to show it's not the geo of the phone itself.

Image

I still feel like I'm missing something with all this noise.

Re: Screens emitting light, and noise

Posted: Tue Dec 09, 2014 8:50 pm
by FooZe
Are you happy to post the scene?

Re: Screens emitting light, and noise

Posted: Tue Dec 09, 2014 10:14 pm
by vmedium
https://dl.dropboxusercontent.com/u/373 ... -forum.zip

Sure, no problem, thanks for your help!

Re: Screens emitting light, and noise

Posted: Wed Dec 10, 2014 12:48 am
by FooZe
Hi, I think this is a bug in the title bar rendering status display. Please refer to the main status bar rather than the title (as seen in the attached image)
main_status.jpg
The only way I can reproduce your problem is this:
1) Open the live viewer and render out the full 500s/px (which is basically noise free). When this is finished the title bar changes to [FINISHED] Rendering:%100 .... 500/500
2) Hit refresh and then pause, which changes the title bar to [IDLE] Rendering %100 ... 500/500 despite the current samples/pixel.

Have you accidentally hit pause?

Thanks
Chris.

Re: Screens emitting light, and noise

Posted: Wed Dec 10, 2014 2:03 am
by vmedium
Definitely didn't hit pause. And I had the same problem rendering to the picture viewer. I'll try again tomorrow and post another screen.

Can you post a fully finished render from your machine just so I can compare?

Re: Screens emitting light, and noise

Posted: Wed Dec 10, 2014 2:19 am
by FooZe
Here is 500s/px on my machine (just opened the file and hit render).
500spp.jpg

Re: Screens emitting light, and noise

Posted: Wed Dec 10, 2014 3:18 am
by aoktar
Hi Fooze and vmedium,
problem is related with materials and geometries. Also i had to copy/paste all to a clean scene. I have edited scene and front glass object. No need double surface, surfaces are very close. It will cleaned be on 500 maxsamples for PT or DL. Let's check the my revised scene.

Best,
Ahmet