Abstract: Solid modeling techniques with precise NURBS surfaces and form features are studied to meet the needs of product modeling in a CIM and concurrent engineering environment.Specif-ics of realizing the Boolean operation of sculptured solids as well as the designing-with-feature processes are outlined.The fonner carries out the set operation of two faee loops on the paramet-er planes of NURBS surfaces and results in a trimmed surface structure,while the latter explicitly locates a child feature on thejoint face of parent feature,bypassing the traditional tedious set operations.Both approaches are useful and should be merged into a parametric,variational and feature-based solid modeler.

Key words: product development, shapes, presentation, models