During the manufacturing process it is very important to estimate the property of materials in terms of orthotropic and anisotropic plasticity. The manufacturing process to obtain a shell of a complex shape from a rolled sheet is considered from the point of analytical geometry, and some specific recommendations are suggested. So-called torso-surfaces are very useful for manufacturing process in many fields of engineering and design, especially in marine and space engineering, industrial design and automobile engineering. Stresses occurring in a metal sheet while it is being bent into a shell with the middle surface of a complex shape are considered from thin shell theory point by analytical and numerical methods. Some numerical experiments are conducted and presented in the work. It is shown in the paper that plastic deformations in most cases occur at a start moment of a bending process, and that special attention should be paid to the products made of anisotropic materials.