Rotation matrix from roll-pitch-yaw angles (default {3 2 1} convention; rotations apply in reverse angle order; optional axis sequence)
RollPitchYawMatrix[{α, β, γ}]
RollPitchYawMatrix[{α, β, γ}, {a, b, c}]
m = RollPitchYawMatrix[{(3π/4), (π/3), (π/3.)}, {1, 2, 3}]
→ {{0.25000000000000006, 0.9185586535436919, 0.3061862178478973}, {0.4330127018922193, 0.17677669529663675, -0.8838834764831845}, {-1/2*Sqrt[3], 1/(2*Sqrt[2]), -1/2*1/Sqrt[2]}}(m = RollPitchYawMatrix[{(3π/4), (π/3), (π/3)}])//MatrixForm
→ MatrixForm[{{-1/2*1/Sqrt[2], -1/2*1/Sqrt[2], Sqrt[3]/2}, {-1/4*1/Sqrt[2], -5/(4*Sqrt[2]), -1/4*Sqrt[3]}, {(3*Sqrt[3/2])/4, -1/4*Sqrt[3/2], 1/4}}](m1 = RollPitchYawMatrix[{α, β, γ}] /. {β -> π / 3})//MatrixForm
→ MatrixForm[{{Cos[α]/2, -1/2*Sin[α], Sqrt[3]/2}, {Cos[γ]*Sin[α] + (Sqrt[3]*Cos[α]*Sin[γ])/2, Cos[α]*Cos[γ] - (Sqrt[3]*Sin[α]*Sin[γ])/2, -1/2*Sin[γ]}, {-1/2*(Sqrt[3]*Cos[α]*Cos[γ]) + Sin[α]*Sin[γ], (Sqrt[3]*Cos[γ]*Sin[α])/2 + Cos[α]*Sin[γ], Cos[γ]/2}}]