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4.19 Physical Lights

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    Originally posted by TCBmbw View Post
    Hi guys,

    I'm just looking for some advice here. I'm following the thread (and tutorials) for a couple of month and I'm also pretty disappointed and confused with this sloppy implementation.
    As a 3D Artist, not lighting artist, I want to use physical lights without a rocket science degree or 1000 workarounds.

    To sum it up - at the moment physical lights are not working properly and I have to eyeball stuff anyway, right?
    So would you suggest to use the "old" exposure workflow and wait till this feature is implemented properly - why should I invest time in something, which does not work the way it should?
    This is no rant, I just ask for some advice regarding this confusing topic. At least, for me it masks no sense to guess (actually breaking) lighting values in an actual physical lighting setup (?).

    Thx
    As of 4.20, everything should be working correctly. There is an issue with Pre-Exposure and Planar Reflections, but that's the only thing I've noticed aside from the various workflow changes people want.

    Even with Physical Units, you will still be eyeballing things, they just make it easier to get to a starting point. Some characteristics of physical units aren't accurate unless you have all the information, like lumens and radiation patterns, lux and season, locale, etc
    Lighting Artist @ Rockstar Games
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      I tried getting it to work in both 4.20 and 4.21 but couldn't get a result that wouldn't make things like the sky and/or the metallic materials look weird. Any metallic surface would get their shiniest highlights turn black when everything broke.
      Is there perhaps a setting I was overlooking?

      Comment


        Originally posted by Sir_Manfred View Post
        I tried getting it to work in both 4.20 and 4.21 but couldn't get a result that wouldn't make things like the sky and/or the metallic materials look weird. Any metallic surface would get their shiniest highlights turn black when everything broke.
        Is there perhaps a setting I was overlooking?
        I had the same result, and I thought it was known to be broken. maybe I also overlooked something?

        anyway I'll try again in 4.22 sometime soon
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          Do either of you have Pre-Exposure enabled in the Project Settings? That has been the fix for going out of range in the past.
          Lighting Artist @ Rockstar Games
          ArtStation
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            Hi all,
            Not directly linked with physical lights, but we need this tool to calibrate the light......
            Has anybody try to use pixel inspector with 4.22 and ray tracing activated (dx12)?
            It seams to not working (by the way, by lauching unreal with dx11 it's ok)

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              If anyone was wondering, I think 1 unitless = 4,000lux and the same 4,000 for unitless>cd/m2.
              Eample... 3.14unitless = 12560lux
              For sky cd/m2 get 5% of the directional lights intensity (628cd/m2 if the directional light is 12,560)

              Tested at EV0 for unitless and EV12 for physical.

              I've got a blueprint set up to convert from lux to the unitless sytem and I haven't noticed any difference using the 1:4000 system assides from the difference in the rendering
              Default unitless (20.96)
              Physical values (83,850)

              Bugs I've encountered while using the physical units, most are a result of the share amount of lux used and the needed support of the old unitless system:
              Broken planar reflections due to required lux levels.
              Broken local lights due to required exposure levels.
              Some gismos and visualisers are not visible due to required exposure levels.
              Legacy emissive materials not visible due to required exposure levels.
              Although shelved, LPV is blown as well due to required exposure and/or lux levels.
              Exponential Hightfog barely rendering, if not at all...

              I'm still new to all of this bull-shittery so take wut I say with a grain of salt :P
              Last edited by DEV_Ethan; 04-17-2019, 03:32 PM.

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                Originally posted by DP Studio View Post
                Bugs I've encountered while using the physical units, most are a result of the share amount of lux used and the needed support of the old unitless system:
                Broken planar reflections due to required lux levels.
                Broken local lights due to required exposure levels.
                Some gismos and visualisers are not visible due to required exposure levels.
                Legacy emissive materials not visible due to required exposure levels.
                Although shelved, LPV is blown as well due to required exposure and/or lux levels.
                Exponential Hightfog barely rendering, if not at all...

                I'm still new to all of this bull-shittery so take wut I say with a grain of salt :P
                I don't quite follow your reasoning behind using unitless, since as long as Inverse Square Falloff is enabled, the output is identical, it's just expressed as a different unit... or lack there of for unitless.

                Planar Reflections don't look like they use Pre-Exposure. They work correctly for me in extremely bright scenes with physical units without Pre-Exposure, but get blown out once it's enabled.

                Broken local lights/legacy emissives due to exposure levels - I'm assuming this is saying you can't see a light because the exposure/relative luminance is too high? Well then that's to be expected. Take a flashlight outside in the direct sun and tell me if you see it If you want to see emissives at all times, regardless of auto-exposure, then divide your final emissive output by the EyeAdaptation node and it will maintain a consistent luminance.

                The Exponential Height Fog issue is identical to the above one. By default, the luminance of the fog is super low, so you need to change the color value to something much higher.
                Lighting Artist @ Rockstar Games
                ArtStation
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                  I wonder if we will ever see some sample scenes from the Unreal team itself. It would be nice to have 4 or 5 pre-set scenes (mid-day, cloudy, sunset, night, interior) to take as reference.

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                    Hi all,

                    I am following this thread since it started and also was playing around with the system. Eventually, I started to put together all the information in a comprehensive talk which I held at the Unreal Meetup Munich last week.

                    As I learned a lot by you guys (many thanks to all of you) I wanted to share my slides with you which should be a good reference for looking up lux values etc. You can find them here: Physically Based Lighting in Unreal Engine 4

                    For me, it worked best to have a mixture of the above mentioned workflows meaning using the Sunny16 chart for initial camera, sky and sun light setup (using the 35-125k lx range), then measuring the received light by using a white fully rough card or sphere and comparing it with the tables until I reach a correct looking light condition which matches with the values. Especially the breakdowns of sun and sky illuminance for some conditions in the lux table help a lot! Finally, I convert the camera settings to EV values for setting up auto exposure and applying some offset to the min ev value.

                    Probably worth mentioning that I was solely using fully dynamic lights for now.
                    Aesir Interactive

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                      Very interesting informations here.
                      Thanks for sharing Lukas.

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                        Originally posted by DP Studio View Post
                        Bugs I've encountered while using the physical units, most are a result of the share amount of lux used and the needed support of the old unitless system:
                        Broken planar reflections due to required lux levels.
                        Broken local lights due to required exposure levels.
                        Some gismos and visualisers are not visible due to required exposure levels.
                        Legacy emissive materials not visible due to required exposure levels.
                        Although shelved, LPV is blown as well due to required exposure and/or lux levels.
                        Exponential Hightfog barely rendering, if not at all...
                        You can add Scene Capture Cube to that list, hope to see some fixes THIS year...

                        Comment


                          Originally posted by imbakeks View Post
                          Hi all,

                          I am following this thread since it started and also was playing around with the system. Eventually, I started to put together all the information in a comprehensive talk which I held at the Unreal Meetup Munich last week.

                          As I learned a lot by you guys (many thanks to all of you) I wanted to share my slides with you which should be a good reference for looking up lux values etc. You can find them here: Physically Based Lighting in Unreal Engine 4

                          For me, it worked best to have a mixture of the above mentioned workflows meaning using the Sunny16 chart for initial camera, sky and sun light setup (using the 35-125k lx range), then measuring the received light by using a white fully rough card or sphere and comparing it with the tables until I reach a correct looking light condition which matches with the values. Especially the breakdowns of sun and sky illuminance for some conditions in the lux table help a lot! Finally, I convert the camera settings to EV values for setting up auto exposure and applying some offset to the min ev value.

                          Probably worth mentioning that I was solely using fully dynamic lights for now.
                          Thanks for that! Very comprehensive quick guide.
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                            Originally posted by DP Studio View Post
                            Bugs I've encountered while using the physical units, most are a result of the share amount of lux used and the needed support of the old unitless system:
                            ...
                            Although shelved, LPV is blown as well due to required exposure and/or lux levels.
                            ...
                            It seems to me LPV's break as soon as you start increasing directional light brightness ever so slightly.
                            At 128K lux you more or less only get primary colors. :/
                            https://www.artstation.com/o2car

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                              Originally posted by william.sch View Post
                              A visual example of using a photographed HDR with photometric numbers in Unreal

                              Click image for larger version Name:	unreal_lighting_sun.jpg Views:	1 Size:	113.4 KB ID:	1545013Click image for larger version Name:	unreal_lighting_sky.jpg Views:	1 Size:	109.6 KB ID:	1545012Click image for larger version Name:	unreal_lighting_both.jpg Views:	1 Size:	105.1 KB ID:	1545014
                              Pixel Inspector luminance readings on white sphere:
                              • sun light only: 4500 (cd/m2) = 14,137 lux
                              • sky light only: 1770 (cd/m2) = 5,560 lux
                              • combined: 6150 (cd/m2) = 19,320 lux
                              These match (close enough to) the illuminace readings I took on location
                              • 18,900 lux in sunlight, facing sun
                              • 5,000 lux in shade, facing same direction
                              • sun+sky - sky = 13,900 sun intensity
                              My actual Sun Intensity is 18,000 lux because its color is very saturated, something else to take in to account.
                              Skylight intensity is at 1.0 "cd/m2", although I still hope they remove the misleading unit label.
                              Pixel inspector show the deepest blue sky at about 720.0 luminance (cd/m2)
                              The skydome material emissive had a multiplier of 23,170 or 14.5 EV.
                              The HDR middle exposure (mentioned earlier) was at EV100 13.32, so I guess you can't just take the EV number and plug it in to your skydome emissive intensity, but it's close-ish. Again the difference is probably due to color saturation. It's always good to have illuminace measurements to be sure, but with most HDRs you'll never know the camera settings or illuminace at time of shooting.

                              The results came out okay. I can use manual exposure or EV100 numbers and it looks pretty close to what I'd expect. Something else to be aware of is I'm not using pre-exposure, so numbers around 65,000+ will start clipping, (at least on my hardware they do).

                              Click image for larger version Name:	unreal_game1.jpg Views:	1 Size:	114.9 KB ID:	1545015Click image for larger version Name:	unreal_game2.jpg Views:	1 Size:	101.5 KB ID:	1545016


                              Btw, 'what kind' of a camera is required to do that/are there TUTS for this procedure ? I suspect you're losing quite a few with this- artists won't have much of a clue( most) .
                              Bringing this into a POV for my own current 2x2 5101x5101 world comp level...only a few stair brushes basically , few trees-deffault sandrock landscape texture- one directional light while enough so far, there is one part of terrain that isn't working as intended, and given 'lighting isn't artist friendly atm, how do I go about getting THIS picture to look like this editor image ?

                              Thx
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                                Originally posted by 2car View Post

                                It seems to me LPV's break as soon as you start increasing directional light brightness ever so slightly.
                                At 128K lux you more or less only get primary colors. :/
                                Looks like thread is VERY dead, wonder why , so did you ever get your lighting and if so what was workiing for you ?

                                thx
                                Solo but Seismic - feel free to apply
                                https://neighborlee1.wixsite.com/theheartseed

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