[BUG] Phong @ IOR = 1

Zom-B · Post by **Zom-B** » Tue Jan 15, 2008 11:55 pm

Phong material having a IOR of 1 shows a darkening on the edges, it seems Energy Loss Compensation isn't applied (correctly).
Its maybe not serious, because why using a Phong mat with IOR = 1 and not a Diffuse mat, but maybe this Bug has some deeper roots...

Vanessa07 · Post by **Vanessa07** » Wed Jan 16, 2008 12:37 am

I thinck phong material with IOR=1 doesn't exist in reality

Post by **OnoSendai** » Wed Jan 16, 2008 12:58 am

Yup, don't set the IOR to 1, it has to be above 1.

Zom-B · Post by **Zom-B** » Wed Jan 16, 2008 1:08 am

I'm just testing further and it seems, an IOR of higher than 1 results also in this "Black Outline Issue", the higher the IOR the less its visible! IOR of 1.01 locks same as 1.00!
I Attached an pic with IOR = 1.1, Exponent = 1000

Zom-B · Post by **Zom-B** » Wed Jan 16, 2008 2:14 am

Hmmm... I rendered the same uniform lightened scene by the same colored diffuse material.

The Diffuse material shows some darkening to the "edges" of the sphere (lol, I hope you understand what I mean).
Shouldn't be an uniform lightened diffuse material in an vacuum be totally uniform colored???

can this be an Reinhard issue...?

Post by **OnoSendai** » Wed Jan 16, 2008 2:27 am

You may be seeing vignetting, use a longer lens.

Zom-B · Post by **Zom-B** » Wed Jan 16, 2008 9:10 am

OnoSendai wrote:You may be seeing vignetting, use a longer lens.

Yes Ono, you are totally right, Vignetting was the bad boy here...

But returning to the Phong & low IOR problem, I can confirm, that there seems to be an issue with low IOR's like 1.025 in the attached image (Indigo 1.0.5).

Post by **OnoSendai** » Thu Feb 28, 2008 10:47 pm

IOR of 1.025 is still too low to be realistic.

Zom-B · Post by **Zom-B** » Thu Feb 28, 2008 11:30 pm

I have no Idea where reality starts, so here an IOR of 1.1, exp 1000000

BbB · Post by **BbB** » Thu Feb 28, 2008 11:54 pm

And here an IOR of 1.40
(Is the problem apparent with low exponent instead of low IOR? Here it's 20 or 30 if memory serves)

Zom-B · Post by **Zom-B** » Fri Feb 29, 2008 12:57 am

Yes, bbb is right there seems an Issue using very low EXP too.
See attached image using IOR = 1.5 and EXP of 1
The whole sphere seems to be darkened

muody · Post by **muody** » Fri Feb 29, 2008 2:55 am

IOR 1.2, exponent 500. sky turbidity 1.9

SmartDen · Post by **SmartDen** » Fri Feb 29, 2008 3:22 am

muody wrote:IOR 1.2, exponent 500. sky turbidity 1.9

you have typically normal smoothing problem. consult the exporter writer for your software

BbB · Post by **BbB** » Fri Feb 29, 2008 3:28 am

muody
Some of this may be normal smoothing errors, I think. The mesh I rendered, however, was highly subdivided so this can't be the problem...

Post by **OnoSendai** » Fri Feb 29, 2008 3:36 am

Yes.. the two problems are related, but not quite the same.

[BUG] Phong @ IOR = 1

[BUG] Phong @ IOR = 1

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