The design of believable emotional characters is the goal of the architecture described in this paper. The novelty of our approach relies on the distribution of the synthetic charactersí architecture in two complementary world models: semantic and physical. The characters emotional state is considered in the semantic world model, implemented as stand-alone Artificial Intelligence module, where general behaviour directives are generated. The agent physical architecture, part of the physical world model, carries out those directives taking advantage of its layered structure. The proposed architecture was used to build the interactive application S3A, a story of dolphins, exhibited in Lisbon at EXPO 98 and featuring two synthetic dolphins.