**Abstract**

Geometric modeling, as widely used synthetic design method in design engineering and manufacturing, is a theoretical base for geometric modeling application (industrial design) and geometric modeling systems (CAD systems). Therefore this chapter is devoted to application geometric modeling methods and systems in design engineering and manufacturing. For example, we will considered designing agriculture machines' tools by following case studies: development models of bulldozer's moldboard by geometric modeling method (for design engineering); screening the concept select process of plow's moldboard (for design engineering and manufacturing); determining integrative role of geometric modeling systems in agro machinery tools' PLM (for manufacturing).

**Keywords:** geometric modeling methods and systems, geometric modeling application, product lifecycle, design engineering, multifunctionality, moldboard's surface, product manufacturing criterions and properties
