At least one turbine component for a gas turbine includes a base component formed by casting and an article. The base component includes a platform. The article on the upper surface of the platform is formed by additive manufacturing. The article has a proximal face sized and shaped to cover at least a portion of the upper surface of the platform of the turbine component and a contoured distal face opposite the proximal face. The contoured distal face has a contour surface serving as at least a portion of a hot gas path surface of the turbine component. The contour surface is arranged and disposed to provide a controlled flow pattern of a working fluid across the contour surface based on a mounting location of the turbine component in a turbine. Methods of manufacturing articles and turbine components are also disclosed.