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Need a piece of advice setting up ilumination for archviz

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    Need a piece of advice setting up ilumination for archviz

    Hi,

    I'm really new to ue4. I have been playing with the engine for some weeks and I really like it. The first thing I did was download the realistic architecture demo and I was really impressed. I want to mimic the lighting of this scene in mine but I'm not getting there. Do anybody know of any documents, etc... to learn to setup lighting the way this project does? I have gone through all the parts this scene has and translating the values to my scene without good results.

    Prior to ask here I have been reading about lightmass, the different light types in ue4, etc...

    If anyone could light my way in this difficult task I would really appreciate it.

    P.D. Perhaps a little explanation about how you imagine the lighting of a scene and how you tranlate to unreal engine would be really interesting.

    Cheers.
    Last edited by fosforestudios; 10-16-2014, 07:38 AM.

    #2
    I could do with the same kinda help.

    Comment


      #3
      Download the lightroom demo made by Koola on the marketplace.

      Basically when it comes to lighting in Ue4 we have 2 choices.

      Lightmass : non-dynamic global illumination with baked shadow maps. When you put your settings very high, it can take many minutes, sometime hours, to build it. But you do it only once. If you move or change an objet you may need to rebuild the light to get accurate shadows. Each mesh you import need properly made uv lightmap. It's the major downside at the moment. This is the solution that gives the most realistic results.

      Lightmass propagation volume : fully dynamic global illumination. The fastest. You don't need to bake shadow maps, you don't need to make a Uv lightmap for each mesh. The results isn't as precise tho. It's better suited fo exterior scenes.

      The realistic demo scene use static lighting, Lightmass, with a directional light and possibly a skylight, i'm not sure.

      Koola's approach was to put reflective planes outside the windows and spot light targeted at them to bounce a lot of light back inside the room. It gives a more realistic feel. He also cranked the settings higher than the standard ''production'' settings.

      2 new features we're added concerning shadows and Ambiant occlusion in 4.5, you should check them out. I'm trying to figure everything out at the moment. Watch the latest Unreal engine stream for more infos on those : http://www.twitch.tv/unrealengine/b/578758490

      Comment


        #4
        Hi,

        Thanks for the explanation.

        One of the things I do not understand is why we have to put more light into the scene to get good results. In the realistic scene we need to add spotlights in the Koola's aproach reflective pannels, etc... I have noticed that reflection probes also gives light to the room. It is a bit odd to get to good results. This is why I was asking about advices. Ussually things are or to light or too dark .

        Cheers.

        Comment


          #5
          I'm not an expert, but from what I understood, the "too much or too much dark" is due to the approximations done during light calculation.

          The most limiting in this case is light bounces. Usually you calculate 2 or 3 bounces, but in reality, light bounces hundreds of times.

          To improve this, you can either add new light sources, or modify the bounce intensity, or add reflection probes. Reflection probes recalculate the light intensity in that point and create a virtual light source with the recalculated light.

          I had the same questions a while a go and the answer is that there's is no standard solution for good lighting, you will have to make your own recipe depending on the scene that you have.

          Comment


            #6
            Originally posted by fosforestudios View Post
            Hi,

            Thanks for the explanation.

            One of the things I do not understand is why we have to put more light into the scene to get good results. In the realistic scene we need to add spotlights in the Koola's aproach reflective pannels, etc... I have noticed that reflection probes also gives light to the room. It is a bit odd to get to good results. This is why I was asking about advices. Ussually things are or to light or too dark .

            Cheers.
            Those extra lights are nothing more than our old archviz friend Sky Portal. Same technique is used in Vray interior renderings to get more light into the room and make the processing faster.

            In Vray (and similar), you basically have two choices:

            1) Use Sky Portal to bring light from outside or
            2) increase (a lot) the amount of photons emitted from the outside lights (sky and/or sunlight) to make it closer to reality (where the number of photons coming from outside is almost infinite).

            The second choice will waste a lot of photons and computing time because a lot of those generated photons won't even enter the room and their effect will not be noticed.

            The same applies to UE4. You could increase the quality of the lightmass messing with the lightmass.ini file. But I don't even know if it's possible to crank those values up enough to get close to VRay results.

            So the best technique to get good amount of light coming from outside and achieve nice results with UE4 is to make use of skyportals.

            ps: The reflection probes won't add light into the room like light sources do. They just enable proper reflection for all the materials in your scene and that will probably make them look brighter (since they have some source to reflect). Adding reflection probes in your scene is a must. And you can't just spread them all over the place without knowing what you are doing, follow those instructions and you'll be fine: https://docs.unrealengine.com/latest...ons/index.html
            Last edited by rabellogp; 06-04-2015, 07:17 PM.
            Guilherme Rabello Co-founder, Sureale
            Artstation | Behance | Youtube | Instagram

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