There are a lot of factors here, the cascade shadows values (distance, exponent, cascade number), the shadow map size, the CMS* variables like “CSMSplitDepthBiasScale”, the orientation of the faces to the light, or the shadowdepthbias. For example with this last:
With a bias of 0.05 the problem dissapears almost totally, but the shadows are less precise, some details are lost, like the belt shadow in the back of the character, or the woods in the house.
You can play with the values, for example with the cascade shadows. You can set the values and find some that don’t produce the stripes. Then move the camera, and the stripes appears again, at other distance, at other angle. It’s very frustrating.
So my plan is:
Try to align the meshes in the map to don’t be paralel with the sun. But this don’t works when the light is totally perpendicular to the ground (12 hours).
Shadow bias will change the value from 0.02 to 0.05, from 8:00 hours to 12, and from 0.05 from 12 to 16 hours. At 12 hours, the sun is vertical and a high bias are not too noticeable. As the day/night cyle are done with code and not matinee for performance reasons, it will be easy to add the bias to the interpolations.
I don’t know if there are any parameter in the ini’s to fix this, I have touched a lot and the only thing that seems work is the bias. Also the pfc shadows can mitigate a bit, but I don’t like the result too much. Perhaps some combination, some hidden option. Who knows (Epic staff appart).