Chaos Corona Forum

Chaos Corona for Cinema 4D => [C4D] I need help! => Topic started by: Benjamin_F on 2019-05-14, 21:05:56

Title: IOR Mapping, 1/IOR like in Corona Max and Vray
Post by: Benjamin_F on 2019-05-14, 21:05:56

Hi,

I would like to know how can I turn off and map the IOR in Cinema 4D/Corona, like in 3ds Max/Corona or Vray.
I want to connect a bitmap or any value with the 1/IOR method.

Thanks in advance.

Title: Re: IOR Mapping, 1/IOR like in Corona Max and Vray
Post by: houska on 2019-05-15, 09:41:27

Hi! The IOR texture slot doesn't work for you?

Title: Re: IOR Mapping, 1/IOR like in Corona Max and Vray
Post by: Benjamin_F on 2019-05-17, 09:54:25

Hi!

Thanks for your answer.

The IOR slot is perfectly fine. What I don't know how can I turn off the IOR number(like 99999 in Max) and control it fully with an 1/IOR map.
I tried different settings, but it not works like it should(Max/Corona or Vray).

Okay, before I posted this, I tried it again and it seems I figured it out.
I have to set the IOR 999 at the maximum to turn it off, and the 1/IOR map needs to be inverted.

Can you confirm that this is the right way?
Anyway why do I have to invert the 1/IOR map? It should be consistent in every application.

Thanks.

Ps.: To be honest I'm not a C4D user, just tried to help to a friend.

Title: Re: IOR Mapping, 1/IOR like in Corona Max and Vray
Post by: James Vella on 2019-09-04, 15:39:51

It seems consistent to 3dsmax for me.

1/IOR is an inverse calculation.
So Black = Frensel Disabled (Vray) or 999 (Corona).
White =  Fresnel 1. (Which would give you a completely black sphere for example)

If you want more information about this I have written a short tutorial on the 1/IOR fresnel calculation here (scroll to the bottom of the page):
http://www.jamesvella.net/blog/2019/9/2/substance-designer-to-vraycorona