Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: DjordjeIlic on 2015-05-08, 11:51:57

Title: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 11:51:57
Hello everyone :),

I have a problem with over bright pixel in reflection and refraction.
In vray I solve these problems with sub-pixel mapping or with clamp output.How can I fix it in Corona?

Render time 3h but is enough...
(http://i.imgur.com/i6pAW1c.jpg)
(http://i.imgur.com/mZjY7L3.jpg)





Thank you very much:)
Title: Re: Reflection/Refraction overbright pixel
Post by: Ludvik Koutny on 2015-05-08, 12:05:13
Usually you would apply glare to these in post. Alternatively, you can increase internal resolution to 2, which will make these softer.
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 12:44:25
Thanks for quick answer,but I know for that.When I render still frame that is not a problem, but when I render animation that is very hard work:) I need a faster and easier solution with a few clicks-like in vray.
Title: Re: Reflection/Refraction overbright pixel
Post by: maru on 2015-05-08, 13:18:25
Have you tried increasing highlight compression?
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 13:47:13
not jet...sounds good
But I don't know how can I use dof and highlight compression at the same time?
Thanks
Title: Re: Reflection/Refraction overbright pixel
Post by: maru on 2015-05-08, 14:47:44
You can change highlight compression directly from VFB or render settings and it will update VFB image in real time. Unless you are using cameramod...
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 15:32:45
I have tried but without success:(
Im sending you a scene,so you can try-maybe I am doing something wrong...?
Thank you very much

https://www.dropbox.com/s/dwd30l8ksu9sc2y/CoronaTeapotsScene.zip?dl=0
Title: Re: Reflection/Refraction overbright pixel
Post by: Siahpoosh on 2015-05-08, 17:37:59
its because your light , just turn off visible reflection / refraction of your sun light
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 18:08:40
ok,but why?
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-08, 18:09:11
I want to have my light in reflection and refraction
Title: Re: Reflection/Refraction overbright pixel
Post by: bazuka on 2015-05-08, 18:43:23
Is there anyone with some logic answer?

this is some kind of a bug, or guys need to implement something like vray has Subpixel mapping, or clamp output...

so would be nice that someone from dev department reply ;)

cheers
Title: Re: Reflection/Refraction overbright pixel
Post by: Ondra on 2015-05-08, 18:46:57
Is there anyone with some logic answer?

this is some kind of a bug, or guys need to implement something like vray has Subpixel mapping, or clamp output...

so would be nice that someone from dev department reply ;)

cheers

This is correct result. Subpixel mapping is incorrect result.

Of course, here the incorrect result looks better. So what you need is some artistic control to be able to remove the higlight. This is already present - for example the ability to disable sun visibility in reflections
Title: Re: Reflection/Refraction overbright pixel
Post by: bazuka on 2015-05-08, 19:38:46
Hm, why would anyone turn off the light visibility? I dont remember that in nature (real life) the light is not visible in relx/refr

Doesnt matter whats correct or incorrect, only thing that matter is what will client say about these dots! I think we dont understand each other...

Title: Re: Reflection/Refraction overbright pixel
Post by: maru on 2015-05-08, 19:54:56
Hm, why would anyone turn off the light visibility? I dont remember that in nature (real life) the light is not visible in relx/refr

Doesnt matter whats correct or incorrect, only thing that matter is what will client say about these dots! I think we dont understand each other...

This is what happens in real life: http://www.vibrakeys.com/wordpress/wp-content/uploads/2011/03/WaterLight.jpg
If you had a "perfect" camera, the result would look like from Corona. To make it look more natural (less perfect - like on that photo) you would have to add glare.
Title: Re: Reflection/Refraction overbright pixel
Post by: DjordjeIlic on 2015-05-09, 06:54:42
Hello guys:),

This is correct result. Subpixel mapping is incorrect result.
Of course, here the incorrect result looks better. So what you need is some artistic control to be able to remove the higlight. This is already present - for example the ability to disable sun visibility in reflections

 
I agree with you Ondra, but I need some kind of artistic control like in vray for example

MAX RAY ITENSITY
(http://i.imgur.com/k45jmXt.jpg)

I know that that is physically incorrect ,but looks better without over bright pixels.Because they look like errors.
When I put down exposure I see that the image is correct

WITH EXPOSURE
(http://i.imgur.com/l6DtpuF.jpg)

WITHOUT EXPOSURE
(http://i.imgur.com/WYXW7qZ.jpg)


But when I look at the regular render I see very sharp highlight...
I have tried to put glow on my render but it looks very bad...

(http://i.imgur.com/DkK2osB.jpg)


If I set my sun on Visible reflection(OFF)
I get a bad result...
(http://i.imgur.com/XrJLlIs.jpg)

but still I have a same problem in refraction
(http://i.imgur.com/WNFqpgj.jpg)

I have found a similar photography,but bright dots are not sharp like as on my render...
(https://c2.staticflickr.com/4/3373/5838153300_f80a014182_b.jpg)

I dont know how maxwell work with these things!?

I tried various glossiness values...
(http://i.imgur.com/sQ3wtUB.jpg)

Solution for this problem is maximum value of glossiness 0.999 because when is 1 we see bright pixels.
(http://i.imgur.com/TjZEcEM.jpg)


Thank you very much!

 
Title: Re: Reflection/Refraction overbright pixel
Post by: romullus on 2015-05-09, 10:20:44
You can try arionfx plugin for pfotoshop (there is a demo). You can add nice looking glare to bright pixels or simply get rid of them. It works very nice 9 times out of 10 :]