Creo Simulate > Modeling Structure and Thermal Problems > Properties > Material Orientation > Default Material Orientation
  
Default Material Orientation
If you do not specify a material orientation, Creo Simulate assumes the following:
For all entities, except shells, the principal material directions are aligned with the WCS axes.
For shells, the principal material directions are defined by the parameterization of the surface, and that:
Material direction 1 is parallel to the first parametric curve of the surface.
Material direction 2 is set perpendicular to directions 1 and 3.
Material direction 3 is perpendicular to the surface and aligned with the surface normal. For information about surface normals, see Surface Normals.