Objects leave a light outline around the cast shadow

It appears that certain shadows have an outline of light while using ShadowMap. It also creates a slight distortion while moving the camera (unable to capture that sadly). The higher the ShadowSoftness, the worse the effect is.

ShadowSoftness on 0.08

ShadowSoftness on 1

Normally it does not show the outline and distortion.

The bug occurs on every 3D objects in the place.

To reproduce I can share the placefile, but only through DM’s.
The bug seems to happen in this place: [UD] Legend of the Eldritch - Roblox

2020-01-17_21-11-24

My videocard: AMD Radeon R9 370
Full details: https://www.dell.com/support/article/us/en/19/sln296972/alienware-area-51-r2-system-specifications?lang=en

I’m not sure when the bug started happening sadly.

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I’ve also seen this bug, but I didn’t care enough to test why it could happen, when, or where, as it didn’t happen everytime.

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What is most likely happening is that the voxels are too big to clamp the shadow. I highly suggest you don’t use 0.08 softness, that usually causes more sharper voxels to appear and it doesn’t look that good. Hope this helped!

I actually noticed this when shadow map was released:

But I forgot about it since

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Not quite sure what you’re saying, but from what I can gather; they’re not asking for help fixing it, they’re reporting a bug.

I’ve also seen this bug occur before, not sure what causes it however. It seems to related to further away objects casting shadows onto shadows cast by nearer objects. I haven’t observed it happening the other way around.

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What I was attempting to say was the best way to avoid it was to increase the softness. Sorry if I confused you.

Not exactly. As stated in my post, increasing the ShadowSoftness only makes the outline larger.

Interesting, I did not see that before. Let me look at the replica.

Edit: I do not see any outlines, did you fix the problem?

Unfortunately, this is a known limitation of Variance Shadow Maps. You get light leaking when two objects that are very far away from each other cast overlapping shadows onto a 3rd object. We may do more shadow map R&D in the future, but we decided to go with VSM for now for its balance of quality and performance.

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Ah okay!
Thank you for the information.

I’d assume VSM is the voxel lighting?
Best of luck! :smiley:

VSM is our ShadowMap implementation.

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Ah thanks! :slight_smile:
I was getting confused there haha

Well, 3 years later and we still get ugly light leaks.

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