Falloff node - Simple HOWTO

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Re: Falloff node - Simple HOWTO

Postby niuq.cam » Tue Oct 23, 2012 9:31 am

Very interesting Fooze. Thank you ! :D
I will also tests.
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Re: Falloff node - Simple HOWTO

Postby archigrafix » Thu Nov 08, 2012 10:45 pm

Fooze
About your architectural glass material: the effect you achieve is called Fresnel reflexion, but I thought unbiased renderer like Octane were capable of this through the IOR value?
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Re: Falloff node - Simple HOWTO

Postby archigrafix » Thu Nov 15, 2012 5:00 pm

Nobody to reply about the fresnel reflections subject????
Surely I will make a topic about that cause it is something important to be precise with IMO
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Re: Falloff node - Simple HOWTO

Postby FooZe » Thu Nov 15, 2012 10:35 pm

Hi archigrafix,

Sorry for the late reply.
Yes, IOR can be used to do this. But the plus side of using a glossy material with fresnel/falloff is that it is more controllable, and does not effect the appearance of the scene through it.
This is a very good thing when using opacity to allow some rays straight though for lighting and casting shadows inside the room. At the moment due to limitations, light will still be "stopped" by the specular material, even if it has full transmittance. Hence the use of opacity to let rays straight through as if the glass was not there.
If you were to use a specular material with IOR and some opacity you would see some strange doubling up of the scene behind the glass. (one for the straight through rays from the opacity, and another from the rays that are effected by the IOR on passing though the specular material).

The glossy material with falloff controlled opacity and full reflection make for a simple, fast and easy solution.

Cheers
Chris.
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Re: Falloff node - Simple HOWTO

Postby Olitech » Thu Oct 09, 2014 6:13 pm

FooZe wrote:Hi archigrafix,

Sorry for the late reply.
Yes, IOR can be used to do this. But the plus side of using a glossy material with fresnel/falloff is that it is more controllable, and does not effect the appearance of the scene through it.
This is a very good thing when using opacity to allow some rays straight though for lighting and casting shadows inside the room. At the moment due to limitations, light will still be "stopped" by the specular material, even if it has full transmittance. Hence the use of opacity to let rays straight through as if the glass was not there.
If you were to use a specular material with IOR and some opacity you would see some strange doubling up of the scene behind the glass. (one for the straight through rays from the opacity, and another from the rays that are effected by the IOR on passing though the specular material).

The glossy material with falloff controlled opacity and full reflection make for a simple, fast and easy solution.

Cheers
Chris.


Is this still a viable workaround for the modern (2014) 2.xx versions?
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Re: Falloff node - Simple HOWTO

Postby FooZe » Thu Oct 09, 2014 9:07 pm

In the latest versions you can use the "fake shadows" option on the specular materials to "let light through" easily.
Have a go and you will see what it does. It will pay attention to the materials transmission and also the IOR in a limited way.
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Re: Falloff node - Simple HOWTO

Postby lukas8410 » Sun Apr 17, 2016 5:10 pm

Useful explanation thanks!
// Behance: https://www.behance.net/LukaszKondek //

- Octane v3
- 1x Geforce 980 Ti , and 1x 570 GTX
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Re: Falloff node - Simple HOWTO

Postby Olitech » Sun Apr 17, 2016 7:40 pm

FooZe wrote:In the latest versions you can use the "fake shadows" option on the specular materials to "let light through" easily.
Have a go and you will see what it does. It will pay attention to the materials transmission and also the IOR in a limited way.


Hi Fooze,

I think we are talking about a Fresnel falloff in the reflection, not the refraction.

Best,
O
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