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How the eye see vs. how VRay Cam sees?

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  • How the eye see vs. how VRay Cam sees?

    Hi all you clever people!

    I find myself forever struggling to get the lighting correct in my scenes because I always try to adjust the lights to what my eyes sees in real life as apposed to what the same thing would look like if I take a photo of it. So in 3D the VRay physical cam is obviously suppose to make the picture look like it was a photo taken and NOT what you would see in real life by looking at it with your eyes.

    I light my scenes NOT like they do it in the movies, but with the actual lights that will be there such as the sun (VRay sun) and the downlights etc that are in the ceiling and walls etc using IES lights. So theoretically everything is physically correct. But now as I say the problem is that I keep catching myself "subconsciously" trying to adjust things as I would see it with my eyes.

    For example if I stand by my door in my bedroom and look into my room in the middle of the day with the sun NOT shining in trough the window, as it is coming from the other side, I can clearly see a bright(ish) room and everything looks normal. Even in the distance the things outside are NOT dark or overblown. So inside and out are "exposed" by my eyes at the SAME time and both in and out looks correct at the SAME time no matter if I focus to something inside the room or outside.

    But now if I take a picture of the same thing, then focusing inside the room makes the outside nuclear bright, and focusing outside makes the inside look like midnight.

    How do I overcome this problem in 3D with VRay by getting a "perfect" picture and should I light my scenes differenlty like moviemakers do it or should I just use the physically correct things or should I keep torturing myself by trying to make it look like when I look at it with my eyes?

    Kind Regards,
    Morne
    Kind Regards,
    Morne

  • #2
    Originally posted by DVP3D View Post
    How do I overcome this problem in 3D with VRay by getting a "perfect" picture and should I light my scenes differently like movie makers do it or should I just use the physically correct things or should I keep torturing myself by trying to make it look like when I look at it with my eyes?
    To me the beauty of CG is that you have complete control over everything. I would say, do whatever looks good to you

    It really depends on different factors; is there anything outside worth seeing? If there is, I raise the indoor light multipliers to unreal values to balance the intensity of the sun and that of the lights inside so everything looks more or less evenly lit. If there is nothing outside worth seeing, then it can be all blown out like a camera photo. Depends on the client too, most people ask me to not blow out the exteriors, as sometimes what's outside is part of the composition or what they are selling. Just because it's the way cameras work does not mean it is the desirable thing to do , like the vignetting on cams. I actually wish cameras someday wouldn't blow out the exteriors, I think a picture looks a lot nicer when you can see what's outside rather than huge white glowing sunlight.

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    • #3
      I agree with rmejia. Although all the physical correctness going on in cg is really amazing, I still think sometimes the benefit of cg is that you can make it look how you, or the client, wants it to look. I'd rather have an unreal but good looking rendering over a physically accurate blown out or dull photo...

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      • #4
        how about a Vray_Eye

        ---------------------------------------------------
        MSN addresses are not for newbies or warez users to contact the pros and bug them with
        stupid questions the forum can answer.

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        • #5
          Originally posted by Da_elf View Post
          how about a Vray_Eye
          heh, +1

          The thing is that your eyes have a very high dynamic range so to reproduce what you see you there are three options that come to me. One, save as float and view on a HDR display, Render several different exposures and tone map it, or tweak the lighting like you like it (cheat).
          Last edited by RErender; 12-04-2008, 09:46 PM.
          Eric Boer
          Dev

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          • #6
            Render out with floating point colors and adjust gamma. This compensates the high dynamic range your eyes can see. It'll probably look flat, because your monitor will only display 0-255 colors. Also your eyes will very quickly adapt to, even locally. So the reason why you see indoors and outdoors properly at the same time is the parts of your eye that see the outdoor have different "exposure" then the parts that see indoors. If you look at the sun, you'll see the afterimage of it even after you close your eyes. So the "correct" way to simulate eye would be rendering out in floating point and then adjust indoors and outdoors lighting seperately.
            http://www.ylilammi.com/

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            • #7
              One way to have semi-consistent results when turning a camera is to set your vraycamera to video. I've actually found this to be most reliable when it comes to rendering scenes and pretty much use it all the time now.

              I wish I could find a specific link that I saw yesterday, but I have to agree with ReRender and MasterBercon.

              A quick search on "HDR Photoshop Tutorials" pulls up the following in which you can compare real-world photos take (from darkly exposed to blown out backgrounds) and what happens AFTER they've been made into a HDR (floating point image.) Just look at the shots and compare the before and after images:

              http://www.cambridgeincolour.com/tut...amic-range.htm
              http://www.vanilladays.com/hdr-guide/
              http://backingwinds.blogspot.com/200...dr-images.html
              LunarStudio Architectural Renderings
              HDRSource HDR & sIBL Libraries
              Lunarlog - LunarStudio and HDRSource Blog

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              • #8
                Originally posted by MasterBercon View Post
                Render out with floating point colors and adjust gamma. This compensates the high dynamic range your eyes can see. It'll probably look flat, because your monitor will only display 0-255 colors. Also your eyes will very quickly adapt to, even locally. So the reason why you see indoors and outdoors properly at the same time is the parts of your eye that see the outdoor have different "exposure" then the parts that see indoors. If you look at the sun, you'll see the afterimage of it even after you close your eyes. So the "correct" way to simulate eye would be rendering out in floating point and then adjust indoors and outdoors lighting seperately.
                Quoted for agreement.
                That's what photographers do anyway: take a few bracketed shots of indoors and outdoors, and patiently mix them in "post" (ie. development / print).
                Lele
                Trouble Stirrer in RnD @ Chaos
                ----------------------
                emanuele.lecchi@chaos.com

                Disclaimer:
                The views and opinions expressed here are my own and do not represent those of Chaos Group, unless otherwise stated.

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                • #9
                  Hi All

                  Thank you for your views and the info. Will do some more tests.

                  Lele I'll download your scripts shorlty and bug you day and night untill I understand how to use them
                  Kind Regards,
                  Morne

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                  • #10
                    Leles scripts are gold to us, definitely worth trying to learn.
                    Two heads are better than one ...
                    ....but some head is better than none.....

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