Abstract: Interruptible rendering is a novel approach to the fidelity-versus-performance tradeoff ubiquitous in real-time rendering. Interruptible rendering unifies spatial error caused by rendering coarse approximations for speed and temporal error caused by the delay imposed by rendering into a single image-space error measure. The heart of this approach is a progressive rendering framework that renders a coarse image into the back buffer and continuously refines it while monitoring temporal error. When temporal error exceeds the spatial error caused by coarse rendering, further refinement is pointless, and the image is displayed. We discuss how to adapt different rendering algorithms for interruptible use and present implementations based on polygonal rendering and ray casting. Interruptible rendering provides a low-latency, self-tuning approach to interactive rendering. To evaluate our results we introduce a "gold standard" approach that measures dynamic visual error against a hypothetical perfect rendering and show that interruptible rendering is more accurate than standard fidelity-versus-performance schemes. This improved accuracy enables better interactive rendering, both for complex models and complex rendering modalities such as ray casting.