Several approaches have been proposed in order to develop intelligent applications on Computer Aided Process Planning (CAPP) domain. These approaches range from historic designs storage for later recovery, to generative synthesis of process plans. Although these approaches present advantages over traditional methods, they have several drawbacks derived specially from the under and over-automation of the decision processes. In this paper a mixed-initiative model for CAPP systems is proposed, that integrates plan recognition of user’s intentions, with planning techniques in the context of artificial intelligence, in order to synthesize new designs that fulfill process planner’s inferred intentions, thus improving the usability and usefulness of such intelligent assistants.