ue-uds-performance-mobile-troubleshooting

Switch Sky Mode from Volumetric Clouds to 2D Dynamic or Static Clouds, use Performance variants of Volumetric Cloud Rendering Mode, lower View and Shadow Sample Scales, and disable Two Layers. Also enable Half Rate Tick and consider Cubemap with Dynamic Color Tinting for the Sky Light Mode.

Set Feature Level in Basic Controls to Mobile first, then configure the Mobile category which defines replacement modes for incompatible Sky Modes. Use the Platform Feature Levels map to set feature levels per platform at startup, and enable Mobile DBuffer Decals for the Space Layer.

Active properties update through an infrequent cache that interpolates values, causing a 1-2 second delay. Call Hard Reset Cache for an instant refresh, or lower Max Property Cache Period in Scalability/Performance to update the cache more often.

The cause is almost always exposure conflicts. Check for post process volumes overriding exposure and disable those overrides, check Game Settings in the viewport Lit dropdown, or disable Apply Exposure Settings in the UDS Exposure category.

Updates overwrite UDS assets, so direct edits to the UDS blueprint are lost, but configuration assets and Sky Modifiers you created survive. Modify UDS through child blueprint classes instead, and always back up or use version control before updating via the Epic launcher.

Engine default Low and Medium scalability settings disable volumetric fog entirely, and UDS does not override scalability cvars. Volumetric fog scalability lives in the Shadow Quality group, so raise Shadow Quality to restore it.