Suggestions for Dynamic Shadows

[mariomguy]

Hello! I'm working on a dynamic open-world game, and I have a few requests for improving rendering with shadows:

• Landscape-specific shadow solver - At the moment, only cascaded shadow maps function on landscape, and they don't function cleanly. It would be nice to have a custom solution very specific for landscape self-shadowing from directional lights.
• RTX support for instanced and foliage actors, as well as landscape.
• Disable contact shadows by material - I find contact shadows look great on bricks and POM materials, but terrible on grass. Ideally the material should have a toggle whether or not to cast or receive contact shadows, but it needs to be somewhere accessible by the landscape grass tool.
• Shadow input for material editor - Not sure if this is possible, but if users can manually access shadows in the material editor, this could allow things like fake shadow maps for landscape and water, or custom shadows for POM materials.

Any info on stuff like this would be really helpful!

[ZacD]

Have you tried 4.23 preview yet? There was some cascade shadow improvements.

I'm sure RTX shadow features will be the coming quickly, still the early days for RTX.

Pretty sure contact shadows are screen space, so a material control seems unlikely.

[Tim Hobson]

Landscape-specific shadow solver - At the moment, only cascaded shadow maps function on landscape, and they don't function cleanly. It would be nice to have a custom solution very specific for landscape self-shadowing from directional lights.

4.23 has some improvements to Shadow Bias with controls for slope bias on light sources and for Directional Lights, you'll have an additional bias control for the cascades to better control biasing over the cascade transitions. See this post: https://forums.unrealengine.com/unre...34#post1616434

RTX support for instanced and foliage actors, as well as landscape.

Supported in 4.23

Disable contact shadows by material - I find contact shadows look great on bricks and POM materials, but terrible on grass. Ideally the material should have a toggle whether or not to cast or receive contact shadows, but it needs to be somewhere accessible by the landscape grass tool.

It's a Screen Space effect. No plans to support control per-Material.

[mariomguy]

The biggest issue I see with shadows is a round, low-poly surface will appear to have flat shading. It occurs on both static meshes and landscape. I find shadow bias just moves the problem forward or backwards, but it doesn't really fix the issue.

I'm so glad to hear RTX support for landscape and instanced actors is coming! I'm ready to jump into that! If this solution can work for both foliage and PDO on POM materials, I'd love to start testing it out.

[spacegojira]

The biggest issue I see with shadows is a round, low-poly surface will appear to have flat shading. It occurs on both static meshes and landscape. I find shadow bias just moves the problem forward or backwards, but it doesn't really fix the issue.

There is a discussion about this problem already: https://forums.unrealengine.com/unre...dows-artifacts

4.23 may or may not ease this problem a littlebit, but it's not going away completely.