ue-uds-lighting-and-shadows

A black scene after adding UDS is an exposure problem. First disable any post-process volume overriding exposure, then check viewport Game Settings under the Lit dropdown, and finally disable Apply Exposure Settings in the UDS Exposure category.

Use Cubemap with Dynamic Color Tinting for dynamic time of day at low cost, since it tints a gray cubemap with fog color and works on every platform including mobile. Capture Based gives hero quality but requires real-time capture support.

Time of Day cannot change at runtime when the sun mobility is set to static or stationary, because baked light mobility prevents rotation. Set the sun to movable using the mobility setting in the UDS Sun category, not on the component itself.

Dark volumetric clouds with a Custom Sun or Moon Light Actor mean Cloud Scattered Luminance Scale is not set on that actor. Copy the exact value from the UDS directional light component, since UDS cannot set it from blueprint.

Add the Light Day/Night Toggle component from Blueprints/Utilities as a child of the light component on your actor. It turns the light on at sunset, animates power-on intensity, and can drive a Light Toggle scalar parameter on dynamic material instances.

The UDS cache system interpolates property changes, so color updates take one to two seconds to appear. Call Hard Reset Cache for an instant change, or lower Max Property Cache Period in the Scalability and Performance category.