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Dynamic Lighting, Reflection and fake GI

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    Dynamic Lighting, Reflection and fake GI

    Hi everyone,

    i know this topic has been discussed before, and i`ve searched pretty much every corner of the web, yet couldn`t figure out how to really go about this.
    For demostration purposes i`ve setup a quick and dirty test environment, which can be seen in the pictures below.
    The scene resembles by no means what i am after in the end, its just to get my point across.

    Now.
    I am trying to create a dynamically lit exterior scene, with mainly spot lights, some point lights, a directional, as well as emissive 'neon light' like materials.
    The neon lights have to have a dynamic GI like effect, as they will be flickering later etc etc.
    Sure you could go and attach a pointlight to a blueprint actor, containing the object with the flickering emissive material and turn it on and off with the flickering, but that leads to another problem, which i will come back to in a minute.
    I managed to create an emissive material that gets reflected very well in combination with a reflection capturem tho it still doesn`t emitt actual light, which is a problem
    If you look at an object, that should be lit by an emissive material, and look towards the emissive material, you get all sorts of nice reflections...

    Click image for larger version

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    but as soon as you go around the object, and look at it from the perspective of the emissive material, there is no light, just some reflections.

    Click image for larger version

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    So far so good, just add a "fill" light with the same color as the emissive material, e voila. Well, not quite. Two problems appear.

    One, if you turn on shadows, to simulate the emissive emitting light and casting shadows, you get wrong shadowing on the emissive object itself. This can be seen in the first image.
    If you turn off shadows in the fill light, you dont get shadows at all, obviously, which results in flat lighting.
    The second problem with the fill light, is that you now get a a strange point light reflection on the lit object , as you can see in the image. the same applies for spotlights.

    Click image for larger version

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    So much for the problems.
    Now, i have no idea on how to go about this, as, i should add, i am fairly new to lighting in unreal.
    As far as i understand, there is no real time global illumination, like what comes with the enlighten plugin (which is a shame btw).
    I see what unreal can do: https://www.youtube.com/watch?v=AdabPy6xQ8A

    But is there any way of doing this dynamic?
    Last edited by DAkAR; 08-17-2017, 01:36 PM.

    #2
    You can use lighting channels to have certain lights not effect certain objects, fixing your shadow issue.

    Source radius also allows you to increase the scale of your point light reflections, up to a point.
    Last edited by ZacD; 08-17-2017, 03:04 PM.

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