#### 10.2.26 SetMatrix3D

• SetMatrix3D( <[vector3D1, vector3D2, vector3D3, vector3D4]> )
• Description: that function changes the current matrix into <[vector3D1,vector3D2,vector3D3,vector3D4]> (thus affecting the projection function Proj3D). That matrix represents the analytic expression of an affine map of the space, this is a three vectors list: vector3D1 is the translation vector, vector3D2 is the first column vector of the matrix of the linear part in the canonical base, vector3D3 is the second column vector of the matrix of the linear part, and vector3D4 is the third column vector of the matrix of the linear part. For example, the mtrix of the identity is : [M(0,0,0), M(1,0,0), M(0,1,0], M(0,0,1)] or [Origin, vecI, vecJ, vecK] (this is the default matrix). (See also the commands GetMatrix3D, ComposeMatrix3D, and IdMatrix3D).
• If $f$ is an affine map of the space, then its linear part is Lf=f-f(Origin), the translation vector is f(Origin), and its matrix is : [f(Origin), Lf(vecI), Lf(vecJ), Lf(vecK)].