A turbine system, comprising: a plurality of transition ducts disposed in an annular array about a longitudinal axis, each transition duct comprising an inlet, an outlet, and a passage extending between the inlet and the outlet and each transition duct further defining a radial axis, and a tangential axis with respect to the circumference of the annular array of transition ducts, the outlet of each transition duct being offset from the inlet along the longitudinal axis, the tangential axis and the radial axis and characterized by each transition duct further comprising an interface member positioned adjacent the outlet and extending around at least a portion thereof for interfacing with a turbine section; and a plurality of convolution seals, each convolution seal contacting the interface member of a corresponding one of the plurality of transition ducts to provide a seal between the interface member and the turbine section and wherein each convolution seal is configured to allow movement of the transition duct about or along the longitudinal, tangential and radial axes (90, 92, 94), the convolution seal including a first outer leg and a second outer leg, the first outer leg and second outer leg having an outward bias in an operating condition; and wherein the interface member comprises a channel, the convolution seal being at least partially disposed in the channel; and the interface member is a first interface member, further comprising the turbine section, the turbine section comprising a second interface member for interfacing with the first interface member, the convolution seal contacting the second interface member to provide a seal between the first and second interface members (142,144). a plurality of transition ducts disposed in an annular array about a longitudinal axis, each transition duct comprising an inlet, an outlet, and a passage extending between the inlet and the outlet and each transition duct further defining a radial axis, and a tangential axis with respect to the circumference of the annular array of transition ducts, the outlet of each transition duct being offset from the inlet along the longitudinal axis, the tangential axis and the radial axis and characterized by each transition duct further comprising an interface member positioned adjacent the outlet and extending around at least a portion thereof for interfacing with a turbine section; and a plurality of convolution seals, each convolution seal contacting the interface member of a corresponding one of the plurality of transition ducts to provide a seal between the interface member and the turbine section and wherein each convolution seal is configured to allow movement of the transition duct about or along the longitudinal, tangential and radial axes (90, 92, 94), the convolution seal including a first outer leg and a second outer leg, the first outer leg and second outer leg having an outward bias in an operating condition; and wherein the interface member comprises a channel, the convolution seal being at least partially disposed in the channel; and the interface member is a first interface member, further comprising the turbine section, the turbine section comprising a second interface member for interfacing with the first interface member, the convolution seal contacting the second interface member to provide a seal between the first and second interface members (142,144).