Stationary light shadows problem

shadows aren’t stable when the subject mesh is near the stationary spot lights.

When the light is movable and shadow is fully dynamic, it’s totally OK .

When it’s a built stationary light the problem occurs.

Actor is about 100 uus away from the light source as you can see.

Is this a bug? What’s the reason for this issue? Thanks for any help.

couldn’t find the way to upload the video, but you can download it from the my google drive link below

  • test environment -

Spot light is facing horizontal direction with its inner/outer cone radius 30 / 60 and Source Radius 0,

No other lights in the scene

Hello STEIN84,

This is not a bug, but just how Stationary lights work versus Movable lights. What you are seeing is expected because you are extremely close to the light source and you seem to be going in and out of the inner radius of the light, which is what provides the stronger darker shadow of the two radii. Keep in mind also that your character has a PhysX cloth coat on, which will cast shadows differently under different lighting conditions if not set up properly. Another thing to keep in mind is to have another light source in your scene somewhere for ambient fill lighting. This helps illuminate really dark areas as well as adding a bit of realism.

If you have any other questions or need additional assistance please let me know.

Thank you,

Andrew Hurley

Thanks for the answer Andrew, but I still got questions about this issue.
( Btw, the screenshot is showing movable light shadow, which is a correct case. The problem is shown in the video )
It occurs to the characters without PhysX cloth on their mesh too, so I guess the reason is independent to the subject primitive’s setting.
As the problem never occurs with the movable light, I guess the shadow projection matrices between stationary light and moveble light are different.
Is this the reason? and why should it be?

You are welcome,

I did watch the video which is what my comments were based upon. For some more concrete definitions and differences between the light types, have a read over the ‘Shadow Casting’ documentation. It will provide you with a bit more insight on how they function.

Shadow Casting

https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/Shadows/index.html

If you have any questions after reading over the documentation, please do not hesitate to ask.

Cheers,

Andrew Hurley