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Lighting advice:Possible to have "reflected light" near an objects shadow with moveable light?

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    Lighting advice:Possible to have "reflected light" near an objects shadow with moveable light?

    Hi, I am test rendering my scenes in 3D studio and one thing I noticed was the renders had a feature that I didn't see in Unreal, which was "reflected light" near the shadow. Is there anyway to reproduce this effect using a moveable directional light? (could also be spot or point if necessary)


    #2
    That's not possible with a movable light, it requires a real-time global illumination solution.
    It can do something like that with static/stationary lights using volumetric lightmaps for dynamic objects. However, that's something that is pre-rendered so it can't be used with realtime lights.

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      #3
      Originally posted by darthviper107 View Post
      That's not possible with a movable light, it requires a real-time global illumination solution.
      It can do something like that with static/stationary lights using volumetric lightmaps for dynamic objects. However, that's something that is pre-rendered so it can't be used with realtime lights.
      Do you know of a way to "fake" it with emissive color?
      I was able to change the color of an object's shadow by plugging a color/constant3vector in the emissive color.

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        #4
        You can use a skylight to add some ambient color but it's just going to be some general lighting that will brighten the shadows, it's not going to be like bounce lighting from one surface onto another.

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          #5
          Originally posted by darthviper107 View Post
          You can use a skylight to add some ambient color but it's just going to be some general lighting that will brighten the shadows, it's not going to be like bounce lighting from one surface onto another.
          I don't think there was bounce lighting in 3D Studio (1993). There's no ray tracing at all in that program- it's all raster stuff.



          I tired to plug in a "color ramp" texture into the emissive color that is lighter where there is reflected light and darker where there isn't, but I can't get it to work.

          Would better to ask the blueprint programming section?
          Last edited by tapirtoon; 09-03-2019, 02:12 PM.

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            #6
            3ds Max had raytracing for a very long time, maybe not when it first came out but at least a couple versions later, with photons for global illumination.

            What you're wanting is a lighting solution, it requires a realtime GI solution, the only ones available in UE4 is raytracing and Light Propagation Volumes (which isn't very good)

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              #7
              Reflection probes will add some of that reflected light. Also if at least the room/area is static and baked, the volumetric lightmaps can add some bounced lighting to move-able objects.

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                #8
                Originally posted by ZacD View Post
                Reflection probes will add some of that reflected light.
                Do they have to be (relatively) smooth reflective objects or will this also work with rough objects?

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                  #9
                  There's a difference between reflection and reflected diffuse light

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                    #10
                    At the outer edge of spheres, there's normally a bit of both.

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                      #11
                      3dmax, even that old, probably have some raytracing GI solution.
                      In UE4 you can experiment with Skylight/direct light. There some settings which add some kind of reflected light from ground.

                      Im currently make some prove of concept for suck a task like roughly approimated dynamic GI:
                      https://youtu.be/2_gWqdZN0Wg
                      Click image for larger version

Name:	UE4QIBL.jpg
Views:	167
Size:	135.7 KB
ID:	1660431

                      But probably for you it would be better to chose: static or dynamic. If you chose dynamic - try RTX, cause LPV are abandoned, and looks like VXGI are also obsolete.
                      In static lighting you have volumetric lightmaps. They static, but can give nice feel of indirect light.

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                        #12
                        Originally posted by tapirtoon View Post
                        I don't think there was bounce lighting in 3D Studio (1993). There's no ray tracing at all in that program- it's all raster stuff.
                        Wow! I got very nostalgic all of a sudden. I have not seen that interface in a looong time.
                        It depends on your use case but LPV´s will work for a movable directional light even if there is no active development at this point.
                        https://www.artstation.com/o2car

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                          #13
                          Originally posted by Alexander.L View Post
                          3dmax, even that old, probably have some raytracing GI solution.
                          It's called just 3D Studio. Max came out in 1996.
                          It was the precursor to Max.
                          Originally posted by 2car View Post

                          Wow! I got very nostalgic all of a sudden. I have not seen that interface in a looong time.
                          .
                          Yes, I'm creating a game that's supposed to be based on late 1980s/early 1990s CGI and I'm test rendering my scenes in 3D Studio for authenticity.
                          Also the old .3ds are backwards compatible with 3DS Max and 3DS Max .3ds models are forward compatible with 3D Studio (with the exception of texture coordinates or any animations with skeletal/vertex deformation).
                          Last edited by tapirtoon; 09-05-2019, 01:58 PM.

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                            #14
                            Originally posted by Alexander.L View Post
                            3dmax, even that old, probably have some raytracing GI solution.
                            In UE4 you can experiment with Skylight/direct light. There some settings which add some kind of reflected light from ground.

                            Im currently make some prove of concept for suck a task like roughly approimated dynamic GI:
                            https://youtu.be/2_gWqdZN0Wg
                            Click image for larger version  Name:	UE4QIBL.jpg Views:	1 Size:	135.7 KB ID:	1660431

                            But probably for you it would be better to chose: static or dynamic. If you chose dynamic - try RTX, cause LPV are abandoned, and looks like VXGI are also obsolete.
                            In static lighting you have volumetric lightmaps. They static, but can give nice feel of indirect light.
                            Does your GI system require RTX and will it work with 4.20? The reason I'm asking is because I'm currently using a custom version of the engine (4.20) that has OIT (order independent transparency) which works well. But it's been abandoned by the person who wrote it.
                            https://github.com/kostenickj/Unreal...420_3_OIT_Main

                            Edit: Also, do you know if your QIBL system works with forward rendering enabled?
                            How trivial/non-trivial is it to enable QIBL?(basically asking if I would be able to have an option in the settings in my game to simply enable/disable it)
                            Last edited by tapirtoon; 09-05-2019, 01:12 PM.

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