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Directional Source Light Shaft issue

Hello, i'm trying to get good rays using light shaft and volumetric fog, but my directional source reproduces a so poor and wrong light shaft. I tested it in multiple projects, and only in my archviz project in 4.19 i can avoid this issue and get good results. I search on the forum but i don't find so much about this.This wrong cast are killing me, and the only way to avoid this issue is completly turn off the light shafts. I use skysphere.On my post process bloom is on default value, exposure is set to 1, but don't bring some diference changing it. Thanks for your attention.

This is the issue:

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Product Version: UE 4.18
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asked Jul 01 '18 at 03:59 PM in Using UE4

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avatar image Kasyad Jul 03 '18 at 05:46 PM


avatar image Zilphy Jul 03 '18 at 06:22 PM

What are your Light Shaft settings in the directional light's properties?

avatar image Kasyad Jul 04 '18 at 04:59 AM

This is my actual settings for directional light source. Bloom on Post process is on default settings.

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Okay I'm not sure what kind of final effect you're going for, but there are many ways to change the way this effect works. I made a video for you that shows me adjusting different things in the world to get different kinds of light shafts, then eventually putting it all together. I am using some weird colors FYI to show the effect better.


To make these effects I'm following a few references. I will put them all below:

UE4 Light Shaft Docs

GDC Volumetric Fog Training

You just need to tweak everything to where you want it. I think in your scene, that bright light beam is from the angle of the directional light being off center towards the camera. Take a look at this video I made showing the beam. As you can see, this will occur no matter how strong the bloom scale is. It is mitigated by the brightness of the sun however, something that is adjusted in the sky-sphere.


Just play around with everything until you get the effect you need. Feel free to ask more questions!

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answered Jul 04 '18 at 02:45 PM

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avatar image Kasyad Jul 04 '18 at 06:31 PM

Thanks so much, i adjust the position of directional source in the way that it matches with sun position in skysphere as you show and the effect looks so much better. And you're completly right, the really problem is my sky sphere, now i know the main point of problem, and can fix it now. Thanks so much.

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