title: Evaluating progressive-rendering algorithms in appearance design tasks.
abstract: Progressive rendering is becoming a popular alternative to precomputational approaches to appearance design. However, progressive algorithms create images exhibiting visual artifacts at early stages. A user study investigated these artifacts' effects on user performance in appearance design tasks. Novice and expert subjects performed lighting and material editing tasks with four algorithms: random path tracing, quasirandom path tracing, progressive photon mapping, and virtual-point-light rendering. Both the novices and experts strongly preferred path tracing to progressive photon mapping and virtual-point-light rendering. None of the participants preferred random path tracing to quasirandom path tracing or vice versa; the same situation held between progressive photon mapping and virtual-point-light rendering. The user workflow didn&rsquo;t differ significantly with the four algorithms. The Web Extras include a video showing how four progressive-rendering algorithms converged (at http://youtu.be/ck-Gevl1e9s), the source code used, and other supplementary materials.
authors.lastname: Jiawei Ou
authors.forename: Ondrej
authors.initials: O
authors.lastname: Karlik
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Křivánek
authors.forename: Fabio
authors.initials: F
authors.lastname: Pellacini