Abstract: In this paper we discuss the design of Performing Animator, an expressive instrument for live media, we developed in support of our situated interdisciplinary performance practice. The concept of a cinema of braided processes is introduced as a basic structure for media instrument design. This media performance instrument is described in terms of its conceptual, design and performative aspects. The Performing Animator Instrument is analogous to a musical instrument that enables generative animation, film editing and compositing, tailored for improvisational expression of projected visual media elements. Design of the instrument evolved based on eight years of development (2003-2011) initiated by a number of interdisciplinary and cross-cultural performance productions as well as inspirations drawn from our study of Balinese Shadow Play (Wayang Kulit). Our instrument presents the performer with a large set of techniques that enable flexible media manipulation and generation. The paper also addresses issues related to the tensions between narrative structure and perfomative expression, live and recorded media and the structuring of improvised media.