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[BUG] Phong @ IOR = 1
Posted: Tue Jan 15, 2008 11:55 pm
by Zom-B
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...
Posted: Wed Jan 16, 2008 12:37 am
by Vanessa07
I thinck phong material with IOR=1 doesn't exist in reality
Posted: Wed Jan 16, 2008 12:58 am
by OnoSendai
Yup, don't set the IOR to 1, it has to be above 1.
Posted: Wed Jan 16, 2008 1:08 am
by Zom-B
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
Posted: Wed Jan 16, 2008 2:14 am
by Zom-B
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...?
Posted: Wed Jan 16, 2008 2:27 am
by OnoSendai
You may be seeing vignetting, use a longer lens.
Posted: Wed Jan 16, 2008 9:10 am
by Zom-B
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).
Posted: Thu Feb 28, 2008 10:47 pm
by OnoSendai
IOR of 1.025 is still too low to be realistic.
Posted: Thu Feb 28, 2008 11:30 pm
by Zom-B
I have no Idea where reality starts, so here an IOR of 1.1, exp 1000000
Posted: Thu Feb 28, 2008 11:54 pm
by BbB
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)
Posted: Fri Feb 29, 2008 12:57 am
by Zom-B
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
Posted: Fri Feb 29, 2008 2:55 am
by muody
IOR 1.2, exponent 500. sky turbidity 1.9
Posted: Fri Feb 29, 2008 3:22 am
by SmartDen
muody wrote:IOR 1.2, exponent 500. sky turbidity 1.9
you have typically normal smoothing problem. consult the exporter writer for your software
Posted: Fri Feb 29, 2008 3:28 am
by BbB
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...
Posted: Fri Feb 29, 2008 3:36 am
by OnoSendai
Yes.. the two problems are related, but not quite the same.