Given are a transformation T (i.e. a rotation matrix (double rotmat[9]) 
and 3 displacements (double dispx, dispy, dispz)),
and the x,y,z coordinates of a point p.

The following code  computes the nx,ny,nz coordinates of T(p):


 nx=rotmat[0]*x+ rotmat[1]*y + rotmat [2] *z+ dispx; 
 ny=rotmat[3]*x+ rotmat[4]*y + rotmat [5] *z+ dispy;
 nz=rotmat[6]*x + rotmat[7]*y + rotmat [8] *z+ dispz;