Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] Bug Reporting => [Max] Resolved Bugs => Topic started by: swork on 2014-02-22, 14:52:15

Title: Burned point
Post by: swork on 2014-02-22, 14:52:15
Guys, need help, please. I can not remove burned point.
Tried everything. What could be the problem?
Thanks in advance.
Title: Re: Burned point
Post by: Ludvik Koutny on 2014-02-22, 14:53:30
I believe those are refractions of the ceiling lights :)
Title: Re: Burned point
Post by: Fibonacci on 2014-02-22, 15:29:17
Guys, need help, please. I can not remove burned point.
Tried everything. What could be the problem?
Thanks in advance.

I think you have to try higher f-number in VRay cam? And for me looks like there the light is too stong in the room. Just check the lamp, that's same too bright.
What light have used? Corona light ?
Title: Re: Burned point
Post by: swork on 2014-02-22, 20:35:51
Yes- Corona light. Intensity 200- 250 . some with  IES
F-numder 4 on physical cam.
Title: Re: Burned point
Post by: Ludvik Koutny on 2014-02-22, 20:56:28
Yes- Corona light. Intensity 200- 250 . some with  IES
F-numder 4 on physical cam.

Yeah, what you see is refraction of those lights :) You can either raise highlight compression parameters, disable visibility of those lights for refractions, or, the most realistic way, just apply some small glares on those points in photoshop, and they will look natural ;)
Title: Re: Burned point
Post by: Fibonacci on 2014-02-22, 21:04:32
Yes- Corona light. Intensity 200- 250 . some with  IES
F-numder 4 on physical cam.

Why are you useing intensity 200-250 ? I think that too much...For my interior I used only CoronaSun with...maximum intensity 1. And one more question: Do you need "extra" lights in the scene? The Sun is not enough?

Are you useing in CoronaSky in the environment slot?
I used in CoronaSky  in the environment slot, and the result was extremly overexposed...Now, I deleted, and woila...now it's much better...
 
Okey this is just an studio render, but much different.
Title: Re: Burned point
Post by: swork on 2014-02-22, 21:05:28
I believe those are refractions of the ceiling lights :)

Thank,Rawalanche =)
I turned off refraction  of all lamps .
  - The situation has improved, but some points still remain. What to do with the rest of?
Title: Re: Burned point
Post by: maru on 2014-02-22, 21:08:16
Yes- Corona light. Intensity 200- 250 . some with  IES
F-numder 4 on physical cam.

Why are you useing intensity 200-250 ? I think that too much...For my interior I used only CoronaSun with...maximum intensity 1. And one more question: Do you need "extra" lights in the scene? The Sun is not enough?

Are you useing in CoronaSky in the environment slot?
I used in CoronaSky  in the environment slot, and the result was extremly overexposed...Now, I deleted, and woila...now it's much better...
 
Okey this is just an studio render, but much different.
I think sun's intensity is different than light's intensity. Sun's intensity is probably taken from physical model. Light's intensity is unitless, it is some fixed value (if it's A5).

Another way to weaken these internal reflections would be to use darker refraction colour for glass or absorption but this would of course change the look of it.
Title: Re: Burned point
Post by: swork on 2014-02-22, 21:12:24
Why are you useing intensity 200-250 ? I think that too much...For my interior I used only CoronaSun with...maximum intensity 1. And one more question: Do you need "extra" lights in the scene? The Sun is not enough?

Are you useing in CoronaSky in the environment slot?
I used in CoronaSky  in the environment slot, and the result was extremly overexposed...Now, I deleted, and woila...now it's much better...
 
Okey this is just an studio render, but much different.


Yes I used the sun and the sky,and for reflections I use hdri. But the room is far from window.
So I had to include additional light sources
Title: Re: Burned point
Post by: Fibonacci on 2014-02-22, 21:22:30
Did you tried shoot off the additional lights ? Or reduce the intensity lower than 10 ?

For me the CoronaSun with 0,1 and lower setup and the VRay skyportal was enought, and after in the post you have a lot of chance to change everything...

You know, just an idea...

And if you changeing the glossiness for the materials...that should be help...

How's about the CoronaLight's directions ? If you got a tighter direction, than you must to change the light's intensity...
Title: Re: Burned point
Post by: swork on 2014-02-22, 22:47:02
Did you tried shoot off the additional lights ? Or reduce the intensity lower than 10 ?

For me the CoronaSun with 0,1 and lower setup and the VRay skyportal was enought, and after in the post you have a lot of chance to change everything...

Light intensity is less than 10 - It will be too dark.
Is VRay skyportal work with Corona?  O_0
Title: Re: Burned point
Post by: Fibonacci on 2014-02-22, 23:27:47
Aham!

I just converted my scene from VRay and the skyportals stand there.

Here is the end of raw render, but if you see there in the mirror the light overexposed.

I'd used only Corona Sun, here is my setups for skyportal and sun, and there is the result...The environment tab was empty. Just simple worked, but I had fixed the materials.

I have only the Alpha5, and I loaded in a week ago...But, I always trying. Specialy the materials "section" :).

If, it's not working for you, sorry but I don't have a better idea...
Title: Re: Burned point
Post by: Fibonacci on 2014-02-22, 23:30:15
...and this is the cam setup...
Title: Re: Burned point
Post by: swork on 2014-02-23, 01:33:00
Yeah, what you see is refraction of those lights :) You can either raise highlight compression parameters, disable visibility of those lights for refractions, or, the most realistic way, just apply some small glares on those points in photoshop, and they will look natural ;)

Thanks for solutions.....
Here if the light setting was  in what is specific units - say, in watts, then it would be much easier to control the correct lighting setup. =)
One more question - if I turn off the light refraction- The image Will the less realistic?
Title: Re: Burned point
Post by: swork on 2014-02-23, 01:40:04
Aham!

I just converted my scene from VRay and the skyportals stand there.

Here is the end of raw render, but if you see there in the mirror the light overexposed.

I'd used only Corona Sun, here is my setups for skyportal and sun, and there is the result...The environment tab was empty. Just simple worked, but I had fixed the materials.

I have only the Alpha5, and I loaded in a week ago...But, I always trying. Specialy the materials "section" :).

If, it's not working for you, sorry but I don't have a better idea...

All the same, I would have included a couple of sources =) When natural light intersects with artificial - the image seems more voluminous.=)
Title: Re: Burned point
Post by: romullus on 2014-02-23, 10:37:12
Here if the light setting was  in what is specific units - say, in watts, then it would be much easier to control the correct lighting setup. =)
To my knowledge Corona's light intensity units is expressed in watts per steradian per square metre (W·sr−1·m−2) http://en.wikipedia.org/wiki/Radiance

One more question - if I turn off the light refraction- The image Will the less realistic?
Most likely it will, but unless you are creating physical simulation, you shouldn't care about that much. As long as your image is looking convincing enough, you can take any artistic liberties that you need to achieve your goals.
Title: Re: Burned point
Post by: Fibonacci on 2014-02-23, 13:04:03
Hmmm....

And how's about the invers square law?

I think that's really important for the light if your goal to make really realistic renders....specialy in the night renders...isn't it?

Title: Re: Burned point
Post by: romullus on 2014-02-23, 13:12:06
If you have any doubts that Corona obeys to that law, just do quick render test and you will see it yourself. Just make sure not to use any highlight compensation, as it will skew visual results.
Title: Re: Burned point
Post by: Fibonacci on 2014-02-23, 14:45:23
If you have any doubts that Corona obeys to that law, just do quick render test and you will see it yourself. Just make sure not to use any highlight compensation, as it will skew visual results.

No, I don't have any doubts about the Corona. Just I'm asking because I did not tried yet...
Now I try to catch the realistic reflections in Corona. :)
Most of the pictures, what I seen, there has a too bright reflections and glossines. That's what I want to stand clear.
Title: Re: Burned point
Post by: Ondra on 2014-02-23, 15:38:21
Don't worry, Corona uses the correct light transport with all CoronaLights having inverse square falloff and no way of changing it.

BTW: this falloff is used in the linear space, after mapping to gamma-corrected sRGB space the falloff is much more flat, nearly linear.
Title: Re: Burned point
Post by: swork on 2014-02-24, 10:59:36
Thanks guys!!!
And please tell me - gamma can affect the burning point. I use a gamma 1.