The incorporation of animation in mathematics teacher education courses is one method for transforming practices and promoting practice-based education. Animation can be used as an approximation of practice that engages preservice teachers (PSTs) in creating classroom scenes in which they select characters, regulate movement, and construct conversations to generate playable animations (Grossman et al., 2009). We focus on the role of animation as a practice-based expression to denote who, what, and how PSTs professionally notice within a mathematics lesson (Jacobs, Lamb, & Philipp, 2010). The animation provides a mechanism for analysis that transfers PSTs' concepts of teaching to a perceptible reality (Lowe & Schnotz, 2008). We examined the affordances and constraints of using animations as a means of supporting PSTs' development of noticing.