Fix dark edges

[Prem_singh]

very high glossy materials getting dark at edges.
In Vray, it is an option in Vray material.
How to fix it in corona ?

[juang3d]

Change the IOR to 20 or so in reflection, this should help.

Cheers

[Prem_singh]

IOR is already at 50.

[maru]

Could you post an example and your material? I suppose it's very lighting-dependant but maybe I'm wrong.

[tomislavn]

IOR is already at 50.

I guess that he meant you should lower it to 20 or some more, like 19. I used to get some weird results in my renders with fresnel IOR of 20+

[Prem_singh]

Its a shader testing scene.
just a simple sphere and teapot.

Viz people HDRI no 3 was used
http://www.samples.viz-people.com/catalogs/HDRI_v1_catalog.pdf

[Ondra]

Some images of setup and result would be nice...

[Adanmq]

If you use 50 IOR you are introducing this curve:


Reflectivity go down to 0.5 close to 90º but you have 0.92 at 0º.

So it´s normal. If you want to remove this effect use a custom curve to describe the reflections you want.



Its hard to see the diference, so you can download both images and compare.




If you are talking about something diferent pelase post some images.

[Prem_singh]

Hi Adanmq
Your first image is the result i want.
can you post a screenshot of your shader connections.

The result I am getting is

[Adanmq]

Hi.
The problem is the high IOR value because the simplified Fresnel formula, You can use a custom Fresnel to drive reflections to avoid this and use a 999 IOR value (to disable corona IOR).
I use a base reflectivity of 92% to mach your 50 IOR value.

Hope this can help you.