Attenuation Radius - Moving SpotLight - Certain angles - No shadow

Development Rendering
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1

What I have been trying to do for the last two weeks: (Seriously, I’ve spent about 100 hours looking up various bug reports and trying everything)

I have a spotlight (as sun) that orbits around 0,0,0 attached to a spring arm (set to 390,000 length)
I have a static mesh (as moon) that orbits around 0,0,0 attached to a spring arm ( set to 375,000 length)

This works correctly however :
I have to set the spot light’s attenuation radius WAY past the slider max of 16384.0 (like 99999)
While rotating the spring arm, and single stepping through frames, you can actually see that at certain angles, the shadows disappear. The closer you get to 90 degrees the more it happens.

I’m pulling my hair out, and now I am at the point of ditching. I understand UE4 was not built for large scale, however UE4 does not have a big red “Let me do it anyway” check box.

As for future answers:
Using Spotlight Attenuation Radius at default max of 16384 does not give me any light above like 1600 distance. (useless)

Must be Moveable/Dynamic (No static lighting)

Distance on SpringArm has no effect, I can use 9000 or 350,000 and it still flickers

This flickers on Landscape, cubes, planes.

Only flickers while rotating spring arm.

Only seems to happen at certain angles

Bounds make no difference.

Stuff like r.shadow ect made no difference

Stuff like r.shadow.spotlight ect made no difference

Disabling occlusion culling in project settings made no difference

Directional light does not cast shadows at large distances

Tried UE 4.18, 4.19

Disabled auto exposure, post processing, blur

Deleted the Config and Save folder, made no difference

Two sided, use as occluder

2

bumping this again

3

Can you provide a Video or some Screen shots of Your problem?

From what I am understanding you are using a Huge Spotlight to Light your scene? have you tried using a directional light instead? I feel like that would be far more useful then a huge spot light.

Are you using any Skylight? If so have you tried disabling skylight shadows?

Also what happens if you disabled Static Light mapping?

Check this guide here for doing so

4

Directional Lights wont give shadows at 400k distance, only the spot light will. But I have to set the attenuation radius to a ridiculous number!

Here is what is in the scene:
Landscape (or plane or static cube, flickers the same) (2000,2000,10 scale)
1 Spring arm (at 0,0,0) with:
1 Spotlight in “outer space” (400k distance)
1 stationary sphere right below spotlight (375k distance)

On event tick:
Get LookAtRotation from Spotlight to 0,0,0 → Set spotlight rotation
Rotate SpringArm 1 degree

Thats it!

228966-new-bitmap-image.jpg
228966-new-bitmap-image.jpg1920×1080 235 KB

5

bumping again

6

Try setting up the delta seconds in your event tag, as i understand it Delta seconds is the time between each frame. perhaps setting it to a small amount like .1 or .5 might fix your rendering issue here maybe the light isn’t playing well with each tick.

Have you tried using Event begin play instead?

i feel Setting up a directional light in your scene should be endless, it doesn’t matter how far away an object is from the light It should light / shadow correctly. without having to stretch a single Spotlight to its limits.

I hope you get this figured out! Cheers!

7

I’ve tried all of that and timers. Its the angle of sun vs terrain that causes it.