06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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EXR 32Bit super white pixels / dots
Hey guys,
im quite sure that some of you know that issue when rendering as a RGBA 32 Bit EXR or Tiff. I got some "artifacts" in my rendering where some pixels in the reflection are just white. Actually they are super white > 5. When i render that scene to a normal RGBA ( 8 Bit ) those pixels disappear and the rendering looks absolutely correct. On the other hand i know that these pixels are just reflections of my scene where some materials colors or lights are over 1.0 - therefore this is the reflection. But i can remember a "trick" to correct those pixels ... Can anyone shed some light ? cheers naik __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Frequenter
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Michael Lampe
Lighting Lead
Buck Design
New York City,
USA
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Try using the rayswitch for the materials with a value over 1. Just put a different texture or color with normalized values in the reflection slot and keep your original material in the default slot. On a side note are you rendering your reflection in separate pass? If so why not just give it a little tonemapping.
Last edited by TaKIKO : 06 June 2010 at 02:22 PM. |
06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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Hm i think i know what you mean.
But in another scene where i use the IBL with a hdr and a color gain over 1 ( 1.6 ) how would you do that? __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Frequenter
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Michael Lampe
Lighting Lead
Buck Design
New York City,
USA
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With the ibl are you up'ing the color gain for illumination purposes? If so to correct your reflections theres a "Adjust Environment Color Effects" options in the render stats maybe try playing with that.
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06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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Also , in some situations you need to crank up the value in order to get
the desired result, wether its a self-illumnated material ( object) or the reflection slot color white --> over white = 1.3 as an example... And of course then you get the super white pixels i think... cheers naik __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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Quote:
If so to correct your reflections theres a "Adjust Environment Color Effects" options in the render stats maybe try playing with that.
yep, i know that function, but why should that differ from the other function in ibl node? I can try this one, but im sure that this will not correct the white pixels... __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Frequenter
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Michael Lampe
Lighting Lead
Buck Design
New York City,
USA
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When you render with the IBL with the color gain boosted what problem are you having. If it is the problem with the reflections what I am suggesting to try is when you boosted the color gain to increase illumination, I would pull the color gain down in the environments color gain to darken what is seen by reflections.
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06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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Perhaps another example.
Consider you have a scene plus an ibl but the color gain is set to 1. Now you have an object with the car paint shader applied to it. In the reflection tab you set the reflection edge weight to 3. Therefore , if the material is highly reflective you will get the super white pixels at some hard edges which is obvious. When i set the value back to 1, i dont get those white pixels but its not the desired look im after.... Now when leave the settings ( edge weight 3 ) and render my scene to normal 8 Bit image - i have the desired result without the super white pixels BUT of course its 8Bit ... so no EXR...... __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Frequenter
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Michael Lampe
Lighting Lead
Buck Design
New York City,
USA
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Ok i think i understand now. So EXR's can't be rendered out as 8 bit? Not sure this would fix your problem but in the framebuffer options check on "Desaturate".
Quote:
Desaturate If a color is output to a frame buffer that does not have 32-bit (floating-point) and half-float (16-bit float) precision, and its RGB components are outside the range [0, max], mental ray clips the color to this legal range.
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06 June 2010 | |
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Hard Worker | Edge Dealer
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Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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thanks again for you comments mate.
I mean the main benefit using EXRs is the fact that it is 32Bit capable including the function that you can render several passes into one EXR. So that would mean that i set the framebuffer back to 8 Bit and still using EXR which is in my view not a real solution. I think you get what i mean. I can remember that i had this issue several months ago. So i rendered an image as 32Bit Tiff but i can also remember that when i saved that one back to an 8Bit ( in Photoshop) that this fixed that issue with the super white pixels. But not this time :-( __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Lluis Barcelo
Eternal Learner
Mexico
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I had the same problem as you, some time ago ... I had randomly pixels burned out, from reflexions. Using mia_materials, and EXR half float. At that time, I gave up, and I had to render the specular pass using maya software. I couldn't find a workaround at all.
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06 June 2010 | |
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Hard Worker | Edge Dealer
portfolio
Naik Zoran
Lead Lighting & Rendering
Munich,
Germany
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Quote:
I had the same problem as you, some time ago ... I had randomly pixels burned out, from reflexions. Using mia_materials, and EXR half float. At that time, I gave up, and I had to render the specular pass using maya software. I couldn't find a workaround at all.
Thats a pity mate.... I just dont get it, im quite sure there are plenty of other users with the same problem... __________________
-- I'm drinking to drown my problems, but these goddamn bastards can swim!!! |
06 June 2010 | |
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Slacker
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Niclas Binnquist
3D Artist
Stockholm,
Sweden
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Read master zaps explaination here:
http://forums.cgsociety.org/showthr...p?f=87&t=543646 |
06 June 2010 | |
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Frequenter
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ray johnson
Neverland
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i think one of the other guys said that already. render in passes and 32bit or half float Exr and use the colorcorrection functionality to bring down the superbright values and and then comp it together, buddy.
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10 October 2010 | |
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New Member
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Filip
Gent,
Belgium
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very nice explanation by Zapmaster:
Read master zaps explaination here: http://forums.cgsociety.org/showthr...p?f=87&t=543646 |
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