Announcement

Collapse
No announcement yet.

4.19 Physical Lights

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    Well, there's also an atmospheric fog and a skylight, both with default parameters. DL and SL are stationary, lighting is baked. No background. With dynamic sun it looks something different, by the way.

    Oh, wait. It looks normal during gameplay. Wha?..
    Attached Files
    Last edited by GranMinigun; 11-15-2018, 10:22 AM.
    Release Kra^W patch!

    Comment


      Originally posted by Daedalus51 View Post
      .. Now the level lighter wants the map when you play it to look exactly like the cutscene to make transitions as seamless as possible (or the other way round, the cinematic guy wants to use level settings)..
      Yeah that makes sense. I don't think we ran into that issue since our cutscenes are a little different, but I guess the only way around that currently is using the EV chart on Wikipedia and matching the manual settings. Interesting idea about the 'tonemapper node' though.

      Originally posted by GranMinigun View Post
      Well, there's also an atmospheric fog and a skylight, both with default parameters. DL and SL are stationary, lighting is baked. No background. With dynamic sun it looks something different, by the way.

      Oh, wait. It looks normal during gameplay. Wha?..
      If something appears different in gameplay vs. editor (or by toggling 'G' in the viewport), then you most likely have something disabled in the viewport properties compared to what is enabled in the Post-Process Volume. Just hit the "Reset Viewport" option to verify easier. It's going to look weird though, because the Atmospheric Sky doesn't reach the average sky luminance by default, so it'll be a bit darker.

      Originally posted by akaChrisV View Post
      I`m also still very confused about all the places you can input different values getting totally different results... but I`d love to understand where I went wrong

      (my scene lights are around 500-5000lm btw and I`m also trying to figure out if those settings are correct. It`s not helpful to see that the unitless value of 1000lm is 49735. that irritates me even more)
      ​​​They should be identical. Just to be sure, you have the new checkbox in the Project Settings enabled that switches the auto-exposure in the PPV to use EV100 and not the f-stop? It'll change the text beside the input

      Setting up lights is a little tedious, purely because there's sooooo many variations with drastically different intensities. I've seen readings of incandescent bulbs from 8 lumens up to 4000 lumens. It's better to just get them in a ballpark and adjust based on artistic liberties, unless you can find specific values for something you're recreating.


      Lighting Artist @ Rockstar Games
      ArtStation
      Twitter

      Comment


        Originally posted by rosegoldslugs View Post
        If something appears different in gameplay vs. editor (or by toggling 'G' in the viewport), then you most likely have something disabled in the viewport properties compared to what is enabled in the Post-Process Volume. Just hit the "Reset Viewport" option to verify easier. It's going to look weird though, because the Atmospheric Sky doesn't reach the average sky luminance by default, so it'll be a bit darker.
        Nah, default and game view are same, only playtest looks normal. But that's because instead of deleting reflection probe I just hid it. After deletion in-game scene also looks alien. And I don't have a post-process volume, forgot to say.
        Release Kra^W patch!

        Comment


          Originally posted by rosegoldslugs View Post

          Yeah that makes sense. I don't think we ran into that issue since our cutscenes are a little different, but I guess the only way around that currently is using the EV chart on Wikipedia and matching the manual settings. Interesting idea about the 'tonemapper node' though.



          If something appears different in gameplay vs. editor (or by toggling 'G' in the viewport), then you most likely have something disabled in the viewport properties compared to what is enabled in the Post-Process Volume. Just hit the "Reset Viewport" option to verify easier. It's going to look weird though, because the Atmospheric Sky doesn't reach the average sky luminance by default, so it'll be a bit darker.



          They should be identical. Just to be sure, you have the new checkbox in the Project Settings enabled that switches the auto-exposure in the PPV to use EV100 and not the f-stop? It'll change the text beside the input

          Setting up lights is a little tedious, purely because there's sooooo many variations with drastically different intensities. I've seen readings of incandescent bulbs from 8 lumens up to 4000 lumens. It's better to just get them in a ballpark and adjust based on artistic liberties, unless you can find specific values for something you're recreating.

          I honestly believe the best we can do here is nail the exterior and then derive what looks good from it for local lights. These values seemed a bit weird for me so far as well (looking again at my example of that 1000 lumens light bulb in my living room and comparing what I photographed from it with in engine results) and I especially struggle with those angle things in regards to lumen.

          If you want to make it really correct, a light (spot) using lumens would need to react according to it set cone angle. Meaning: while having the same amout of energy distributed, the perceived brightness varies greatly depending on covered surface (read: angle of distribution).

          So there is that as well^^

          Cheers^^
          Last edited by Daedalus51; 11-16-2018, 02:55 AM.
          Check out UNREAL 4 Lighting Academy
          https://forums.unrealengine.com/show...ng-like-that-)

          Comment


            So... I've done a little experimentation with my scene and found something interesting. Maybe a bug.
            Same setup: stationary directional and sky lights, atmospheric fog, and one sphere reflection probe. Everything at default settings, with the exception of DL: its intensity is set to 70000 lux.
            On the first screen is how scene's lighting normally looks with reflection probe (the intended look). On the second one reflection probe is hidden (or deleted, doesn't really matter) - materials go wild, sky is normal, and it looks like that the guy at the right side is the only survivor. Note that if we'll check reflections visualization, there won't be any wild overbright. But if we'll turn specular off, like on the third screen, - everything's back to normal (well, mostly).
            Release Kra^W patch!

            Comment


              I feel like some sort of better documentation or explanation on what has been changed is really needed. Ideally it would be a good idea to have Epic do a livestream with the people responsible for the implementation explanaing the new system and addressing common complaints from this thread and previous workflows.

              If not, someone from the community that can get all the nuances. I'm familiar with photography terms but not a pro lighter and reading this discussion on the current state of things did nothing to clarify what's going at the moment and would make me rely on eyeballing values as always anyway.
              Last edited by MDiamond; 11-19-2018, 08:35 PM.

              Comment


                Originally posted by MDiamond View Post
                I feel like some sort of better documentation or explanation on what has been changed is really needed.
                One thing that did not make the documentation with this most recent update for 4.21 is a section detailing the workflow for using the PLUs and Auto-Exposure. It's something that I want to add along with some reference values to use for different lighting situations (ie, sunny day, overcast, night, etc) that are in line with what you can find on other sites with tables of exposure values (for example, Wikipedia).

                Just know that it's still on our minds to add these things and reduce the confusion (as much as possible). Unfortunately, I don't have an ETA, but I'll push to get something added before the end of the year (which isn't really that far off!).

                Tim Hobson | Learning Resources | Epic Games
                UE4 Documentation

                Comment


                  For me this whole physical light thing is still not working out at all.. I tried to setup a night scene based on this rule here... https://en.wikipedia.org/wiki/Looney_11_rule
                  After importing and tweaking my custom HDRI Skybox and camera values, Shutter Speed 200, ISO 200, F-Stop 7 to 11 i throw in a Pointlight in my scene with a value of 900 lumen or 1300 lumen and i see nothing... the light is still pitch black. Values above 100.000 start to give me some light which is kinda crazy.

                  Comment


                    Originally posted by A-J-K View Post
                    For me this whole physical light thing is still not working out at all.. I tried to setup a night scene based on this rule here... https://en.wikipedia.org/wiki/Looney_11_rule
                    After importing and tweaking my custom HDRI Skybox and camera values, Shutter Speed 200, ISO 200, F-Stop 7 to 11 i throw in a Pointlight in my scene with a value of 900 lumen or 1300 lumen and i see nothing... the light is still pitch black. Values above 100.000 start to give me some light which is kinda crazy.
                    For a night scene that's not correct - The Looney Rule is meant for taking pictures of the moon/moon's surface, not a whole night scene. You can get a better idea of a night scene exposure here: https://en.wikipedia.org/wiki/Exposu...xposure_values

                    I'm still personally struggling with the candela/lumen units. I still feel like I have to multiply all the units by 10-100 to "feel" right and that's frustrating not knowing for sure. Daedalus51 mentioned this very early on in this thread, but I haven't really seen a response for it, unless I'm missing something.

                    Some documentation/example scene I think would do wonders for a lot of questions here in this thread.
                    Lighting Artist - Defiant Studios

                    Comment


                      Originally posted by k.mermelstein View Post

                      For a night scene that's not correct - The Looney Rule is meant for taking pictures of the moon/moon's surface, not a whole night scene. You can get a better idea of a night scene exposure here: https://en.wikipedia.org/wiki/Exposu...xposure_values

                      I'm still personally struggling with the candela/lumen units. I still feel like I have to multiply all the units by 10-100 to "feel" right and that's frustrating not knowing for sure. Daedalus51 mentioned this very early on in this thread, but I haven't really seen a response for it, unless I'm missing something.

                      Some documentation/example scene I think would do wonders for a lot of questions here in this thread.
                      Yeah i also saw the video from Daedalus51 but i was thinking that this "issue" is kinda fixed since we are what 2 UE versions ahead from the version he is using in his video ?
                      Lumen and Candela values are so off for me no matter if i try a day interior scene with interior lights or a night scene.

                      Ouh i thought the looney Rule was kinda the oposite of the sunny 16 rule, thanks for clarifying this. I can't find any night values on the wiki page you have shared... What would be the right values for a night scene/night interior scene ? I guess Shutter and ISO at 100 and a low F-Stop value ? i also had some problems to find the lux values for the moonlight intensity. Wiki says for full sun light 100K to 125K Lux, for moonlight it says 0.1 to 1 Lux, which seems kinda low for me.

                      Comment


                        Originally posted by A-J-K View Post
                        Wiki says for full sun light 100K to 125K Lux, for moonlight it says 0.1 to 1 Lux, which seems kinda low for me.
                        That's correct. The range between the sun light and pretty much anything else, practical or natural, is extremely high. Even the range of the sun itself between noon and sunset is pretty extreme. The Lux values also include the sky contribution, so your light value will be slightly lower.

                        For night time exterior, you'd use an EV of -6 to 4, depending on what type of light your subject is under, including moon phases. For night interiors, an EV of 4 to 8 also depending on what type of light is used. If you want to use the manual controls, pick from the chart here that corresponds to your desired EV and f-stop. https://en.wikipedia.org/wiki/Exposu...amera_settings
                        Lighting Artist @ Rockstar Games
                        ArtStation
                        Twitter

                        Comment


                          Originally posted by rosegoldslugs View Post

                          That's correct. The range between the sun light and pretty much anything else, practical or natural, is extremely high. Even the range of the sun itself between noon and sunset is pretty extreme. The Lux values also include the sky contribution, so your light value will be slightly lower.

                          For night time exterior, you'd use an EV of -6 to 4, depending on what type of light your subject is under, including moon phases. For night interiors, an EV of 4 to 8 also depending on what type of light is used. If you want to use the manual controls, pick from the chart here that corresponds to your desired EV and f-stop. https://en.wikipedia.org/wiki/Exposu...amera_settings

                          That means a value of 1Lux for the directional light "moon" is correct? The problem i have with the current physical lighting setup in Ue4 is, 1Lux gives me no lighting at all in my scene.
                          I also have a problem with this data charts, i don't really know how to match the terms in the charts with the editor ones, f number is a clear thing, it's the f-stop in the editor... values like 1/125, 1/100 or 1/30 are the shutter speed values.. but where are the ISO numbers ? I guess they are always the same like the shutter speed? And what is EV ? Exposure Values... Is it the Min and Max Brigthness in the Exposure tab ? or the Exposure Compensation value ?

                          The chart gives me also shutter speed values like 1 or 2 or 60, without the 1/ , the same goes for 2m, 4m, 8m, up to 256m and so on... how should i use this values ?

                          And for the simple sunny 16 rule setup like from Daedalus51's video, Lumen and Candela values are still absolutely not working for me.
                          Last edited by A-J-K; 11-20-2018, 10:28 PM.

                          Comment


                            Originally posted by A-J-K View Post
                            That means a value of 1Lux for the directional light "moon" is correct? The problem i have with the current physical lighting setup in Ue4 is, 1Lux gives me no lighting at all in my scene.
                            I also have a problem with this data charts, i don't really know how to match the terms in the charts with the editor ones, f number is a clear thing, it's the f-stop in the editor... values like 1/125, 1/100 or 1/30 are the shutter speed values.. but where are the ISO numbers ? I guess they are always the same like the shutter speed? And what is EV ? Exposure Values... Is it the Min and Max Brigthness in the Exposure tab ? or the Exposure Compensation value ?

                            The chart gives me also shutter speed values like 1 or 2 or 60, without the 1/ , the same goes for 2m, 4m, 8m, up to 256m and so on... how should i use this values ?

                            And for the simple sunny 16 rule setup like from Daedalus51's video, Lumen and Candela values are still absolutely not working for me.
                            1 Lux will only be visible if your exposure is correct. Night time can get into the negative EVs, so 1 Lux will absolutely be visible then. EV is a simplified way of talking about exposure. Just gonna quote myself here cause I'm lazy
                            Originally posted by rosegoldslugs View Post
                            It's a single unit based on shutter speed, ISO(generally 100), and f/stop to where any combination that has equal exposure to another combination would use the same EV. Instead of worrying about the individual settings, you can use the EV input. Plus, it provides a real-world measured reference that can get you 90% of the way there just like other physical units. For instance, interiors will likely be around 4 - 8 because of the average luminance found in interiors, but with Auto-Exposure now directly using EVs, we can also adjust for the exposure outside if you get near a window, like up to 13 for the overcast day outside in my scene...

                            ...An EV of 5 is identical to a shutter speed of 1/4s with an f-stop of 2.8 at ISO 100. It's also identical to a shutter speed of 1s, ISO 100, and a f-stop of 5.6 because both combinations of settings will result in identical exposure. EV5 is just a simpler way to put it.
                            They're used in the engine by default as the viewport exposure override, unless you enable the extended range option in the Project Settings, which will replace the Min/Max Exposure values for EVs in the Post-Process Volume. Regardless, the Manual mode can achieve identical results, you just have to convert the single EV value to the individual camera settings.

                            To use the chart for matching EV to manual settings, just set your Post-Process Volume's Metering Mode to Manual and set the correct values down in the Camera section. Most measurements will be based on ISO 100, that chart included. So because of that, and because the Shutter Speed input is limited to 1/1(1 second), some of the chart is irrelevant. You could do some math to get the required Shutter Speed and F-Stop for a different ISO, but since the manual settings don't really change anything else it doesn't matter imo.

                            Considering that the Sunny 15/16 rule is targeted towards exposing for a subject in direct sun on a clear day, I wouldn't expect your every day light to be visible then. It's the same concept of your car's headlights not visible during the day, excluding the actual light emitting surface since that is always waaaaay brighter. Or your phone screen not being visible out in the sun or it blinding at night.

                            Last edited by rosegoldslugs; 11-21-2018, 12:39 AM.
                            Lighting Artist @ Rockstar Games
                            ArtStation
                            Twitter

                            Comment


                              @rosegoldslugs


                              Sorry to butt in, but I've got some questions. I'm not sure how shutter speed works with UE4, generally I've heard for video with DSLR cameras, you want to lock the shutter speed to half the frame rate, in order to get an appropriate amount of motion blur. I doubt exposure/motion blur work the same in game engines as they would on a camera (motion blur is a post effect controlled with a value not linked to the camera shutter speed, right?). If shutter speed doesn't directly effect the motion blur, why would you use that over just changing the iso? There's no downside to cranking up the ISO since you don't have to deal with camera noise.

                              Or am I miss understanding how ISO and shutter speed work in UE4.


                              I probably just need to play with the camera settings more, I've mostly just played with the exposure values and ignored trying to use it like a DSLR.

                              Comment


                                Originally posted by ZacD View Post
                                @rosegoldslugs


                                Sorry to butt in, but I've got some questions. I'm not sure how shutter speed works with UE4, generally I've heard for video with DSLR cameras, you want to lock the shutter speed to half the frame rate, in order to get an appropriate amount of motion blur. I doubt exposure/motion blur work the same in game engines as they would on a camera (motion blur is a post effect controlled with a value not linked to the camera shutter speed, right?). If shutter speed doesn't directly effect the motion blur, why would you use that over just changing the iso? There's no downside to cranking up the ISO since you don't have to deal with camera noise.

                                Or am I miss understanding how ISO and shutter speed work in UE4.


                                I probably just need to play with the camera settings more, I've mostly just played with the exposure values and ignored trying to use it like a DSLR.

                                No I'm in the same boat as you. I don't see the point in even using the manual options. The cinematic camera/ new DoF are based on physical sensor and lens settings, but I haven't seen anything where they're tied together so really I have no idea what else they'd be used for other than people wanting to match a particular setup for a very specific reason.
                                Lighting Artist @ Rockstar Games
                                ArtStation
                                Twitter

                                Comment

                                Working...
                                X