Base materials in exported Datasmith files imported into Unreal Engine are missing material function.

Datasmith imports in UE do not render materials due to missing material function.

Works in UE 5.6 main but not UE 5.5 or 5.4

Export any Twinmotion scene as Datasmith to a UE project (works with template projects)

Import that Datasmith scene to Unreal Engine.

See how materials failed to compile. Inspect parent materials.

Can go into parent materials (M_TMStdOpaque) and hook up pins, skipping the missing material function.