Lighting Study - City Subway Train UE4

Hey all

First time posting here in a long time. I'm trying to get better at lighting so after a 8 month break from portfolio work I got a free asset from the UE4 Marketplace and had a mess around. Below are my initial results, I'm pretty happy with them but I'm having a bit of trouble knowing where to go with this scene now. 

I've used the rectangular light heavily in this scene and used some point lights to fake bounced lights in areas around the light sources, I've found that to get those areas right I was turning the intensity up so much it was washing out the rest of the environment, so I decied to fake it with another light. I've got IES light profiles on all the lights but the aformentioned point lights and I've gone into the console commands and turned up the SSR quality to try and reduce the grainy reflections I was seeing before.

My plans going forward is to create a flashing light at the darker end of the carriage, I'm trying to create a darker end so the light above the door really draws the eye but there's more work to be done there. Will be adding in very minimal height fog and I've created a basic dust particle fx. Open to any and all suggestions as apart from what I've mentioned above I've hit a bit of a roadblock with this one.

Also having a problem with the light complexity optimization view mode if anyone knows of this issue and a way to fix it please let me know.


  • Will1313A
    So I'm wrapping this project up for now pending some feedback. Quite happy with the results, spent while learning how to impliment animating light sources into a scene which was a learning curve but has yeilded some cool and atmospheric results I think. Feel Free to comment with any feedback or thoughts on how to improve. It would be greatly appreciated.

    Models and Textures by Dekogon Studios

  • JamesBrisnehan
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    JamesBrisnehan greentooth
    The reflections in the windows are trippy. Very "fish-eye lense" looking. Also I'm not sure windows are that reflective at these angles. Maybe some more fresnel effect would look nice? Anyway I really like the lighting so far. It looks pretty realistic.
    One thing that might be fun to add would be panning lights and textures outside the windows to simulate a tunnel going by. Especially if the tunnel lights are a complimentary color to the train interior. (Or maybe that's just a thing at the Denver airport. I don't really know what New York trains are like.) 

    DIA example (Skip to 2:40):
  • rexo12
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    rexo12 polycounter lvl 3
    Did you end up fixing the light complexity visualiser? I've found that going to Show -> Use Defaults in the viewport tends to fix those sorts of issues.
  • teodar23
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    teodar23 polygon
    Your lighting is so complex, even light complexity mode gave up :)
  • Will1313A
    rexo12 said:
    Did you end up fixing the light complexity visualiser? I've found that going to Show -> Use Defaults in the viewport tends to fix those sorts of issues.
    Hey, thanks for that tip it kind of worked! So I can now see the complexity of dynamic lights but I'm still having the same issue with static and stantionary lights inside blueprints. Is there any reason lights in blueprints or baked lights wouldn't show up in this view mode? I've attached a screenshot below of what I'm seeing now.

  • JamesBrisnehan
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    JamesBrisnehan greentooth
    It might be that baked lights don't impact performance in the same way. I think baked lighting is saved and loaded more like texture maps. So the main job of the 'light complexity visualizer' might just be to show where dynamic lights are overlapping so you can avoid over-doing it. Unreal doesn't seen to like more than 4 dynamic lights to overlap in the same spot. Maybe it takes a little too long to calculate 5 lights in the same place or something. I'm not 100% sure though. I'm still figuring out Unreal's lighting myself.
    On my last scene I had too many 'stationary' lights too close together and Unreal would place a big fat red 'X' over some of them and give me error messages after baking. The light complexity visualiser showed the areas in red as well. Setting the lights to static (baked only) fixed it though.
  • Will1313A
    Hey James 

    The reason UE4 only lets you have up to 4 stationary lights in one area is because the shadows are being baked into a distance field shadow map and they only have four channels. That's the reason they only allow four in one area, the big red X that appears over the light when there's more than 4 stationary lights in one area means that the light with the X will revert to a dynamic light and won't be baked at all. 

    I got this information from here about 15 mins in, he talks about it for 4 or 5 mins. Also excellent series of videos about lighting I would highly recommend -

    Now you mention it, it does make sense that only dynamic lights would appear in that visualiser. I know in my next scene I'm planning on doing an exterior so there's more oppourtunity to have dynamic and stationary lighting set ups there.

    I did do some work on the "fisheye" reflections although I ran into a bit of a problem. If I used a box reflection capture they the reflections became really weak, you could barely see anything at all in the windows even if I turned the resolution of the reflections up really high (tried 2048px). Planar reflections worked perfectly but when I put one on both sides of the carriage the other would stop working. I don't know if there are limitations to only having one planar reflection in the scene or maybe they can't be facing each other to avoid the infinity mirror effect which I imagine might set a GFX card on fire. So for this reason I've stuck to spherical reflection capture actors, I don't know if there's a magic tickbox somewhere that fixes the fisheye look to it but it's the best results I can get for now. I did make a slight change however, before I was using a Cubemap on all of my reflection capture actors and this resulted in more distorted and innacurate reflections. To fix this I've removed the cubemap from all of the smaller reflection capture actors in the scene and just left it on the box reflection capture that encompasses everything.

    These are the results:



    You could definitely argue that the reduction in the distortion is minimal but I'd say it's a better overall result. Also played fresnel on the glass but if I changed the settings too much the upper section of the windows would start to look very distorted so I decided to leave them alone for now.
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