Light Mass Ignoring Sky Light

Development Rendering
1

Hello everyone,
Trying to get into UE4. I’ve watched a few of tutorials online, so I think I have a decent understanding of how rendering works in unreal.

But I noticed, it seems the light baking process ignores the skylight for me. It seems to work well in the videos I watched, but the result on my computer is always different.

I’ve attached pictures to help explain.

First pic shows the skylight set to stationary as it appears in the viewport before baking

Second pic shows scene after light bake - I’ve tried setting the skylight to static and stationary and even tried “recapture” before baking, but the effects of the skylight is ignored after baking

I’m using 4.19.2. Is it possible there are settings for this version I’m missing, cos most of the tutorials I’ve watched are for a few versions back?

It’s driving me nuts, please help.

2

Seems really weird, this should not happen. Can you try using a HDRI in the sky light and then build lighting. Also, just check if cast shadows are enabled (should be enabled by default)

3

Thanks for the reply. It gets weirder - it “behaves properly” when I actually disable cast shadows instead. I don’t think this counts as a proper solution though.

4

Hi!

I don’t really see the problem to be honest! :S What were you expecting to happen or look different?
Could you post us a screenshot with ONLY skylight enabled from all your lights?
Also could you tell us more about your settings? Like lightmap resolution of the walls, lightmass settings… what helpers you use (portals, Lightmass Importance Volume…)

5

Hi, thanks for the reply. I’ll try to explain better

6

Basically I’m not getting the effect of the skylight after LightMass calculations unless I set the check cast shadows off

There is a Lightmass Importance Volume. Lightmass resolution on the walls were initially 124. Increased to 512, still had the same effects ( with better shading of course)

Also tried with and without LightMass Portal, still got the same effects.

7

Hi!

I’m sorry but I still don’t see the error… :S
I still see that skylight + shadows on a lot more realistic than shadows off…
To be honest your skylight’s bounce is set to 1 so you won’t get much GI from that… other lights set to 3…
…also all your other lightmass settings (+lightmap resolutions) are very low so don’t expect very good results…

8

I do agree the scene doesn’t look realistic after the addition of the skylight, but that’s not the point. I’m actually following a tutorial, so I’m not getting the same results using the exact same settings from the tutorial.

The point is, the scene without skylight after lightmass calculation looks exactly the same as the scene with skylight after lightmass unless I turn off cast shadows.

My concern isn’t about aesthetics at the moment - the problem is skylight not behaving the way it should after lightmass calculations at least based on the videos I’ve watched

I’ll try installing 4.20 later today to see if I get the same effect and maybe check for more recent tutorials

9

Sorry what I said was that is DOES look more realistic after you add the Skylight with casting shadows and build the light!! …the other one is way too unrealistic and bright IMO…
I’m not sure what tutorial you’re watching for which release… the multibounce Skylight exists (officially) since 4.18 if I remember well so maybe the tutorial you’re watching didn’t have this option yet…
BUT again: you set your Skylight to have just a single bounce: you won’t see much result from it…