4.14.0 dynamic lightning leaking through meshes

[MyGreatUsername]

First time I noticed this problem was when I attempted to migrate my 4.12.5 testing project to 4.14. The basic meshes from the Starter Content are passing some lightning from the movable Spotlight source.

Two things I noticed:

• in 4.14 the spotlight intensity needs to be set extremely high (mostly to maximum) to achieve the same visual effect rather than in 4.12.5 (also, changing the intensity in 4.12 does not change anything leak-wise, and the light stays blocked as it should),
• the view angle is affecting the specular area from the leaking lightning when it’s changed from the sharp angle (most intensive specular spots) to obtuse angle.

What I have done in attempt to fix the problem, or at least making something that would affect it by bringing any change (saying in short - nothing of this helped):

-switched rendering modes, forward/deferred combined with DF on/off

-changed DF and shadow parameters in meshes, including the “two sided” option

-adjusted every possible option in the lightning source with no effect (except the intensity part of that I mentioned earlier)

-post process is not affecting the problem at all

Here is the similar setup on a clean First Person template I used to recreate the problem (ForceNoPrecomputedLighting is ON):

And this is how it is looking from the problematical side:

The unwanted specular spot disappear when the view angle is changed (both in editor or in game mode):

Is anyone having the same problem, or ideas on what might be causing it?

[Tim_Hobson]

Hi Ashh,

There isn’t any real difference in how this was handled between 4.12 and 4.14.

What you’re seeing here with light leaking is normal. You can adjust the shadow bias to help block this and make your asset more grounded with shadowing.

You can read about that here: Content Examples Sample Project for Unreal Engine | Unreal Engine 5.1 Documentation

With Spot Lights and even Point lights, the larger the radius the lower the shadow bias will need to be to accommodate but then if it’s too low you’ll run into self-shadowing artifacts. Find the balance that works best for your design.

-Tim

[MyGreatUsername]

I tried the shadow bias adjustments, in such a number of variations that the French lord who invented the BDSM (I just forgot his name) would say “WOW!”, trust me. But the same setup is looking in 4.12.5 like this:

While in 4.14 it is appearing like this, and the specular spots can’t be removed:

With the huge respect to your authority, and i’m not kidding, i have to say that it’s different. Hugely different.

[MyGreatUsername]

P.s.: It’s exactly the same scene with exactly same parameters.