Evaluating Progressive Rendering Methods in Appearance Design Tasks

J. Ou, O. Karlik, J. Krivanek, F. Pellacini
IEEE Computer Graphics and Applications, 2013


Progressive rendering is becoming a popular alternative to pre-computation approaches for appearance design tasks. Images created by different progressive algorithms exhibit various kinds of visual artifacts at the early stages of computation. We present a user study that investigates the effects of these artifacts on user performance in appearance design tasks. Specifically, we ask both novice and expert subjects to perform lighting and material editing tasks with the following algo- rithms: random path tracing, quasi-random path tracing, progressive photon mapping, and virtual point light (VPL) rendering. The experimental result suggests that path tracing is strongly preferred to progressive photon mapping and VPL rendering by both experts and novices. There is no indication that quasi-random path tracing is systematically preferred to random path tracing or vice-versa; the same holds between progressive photon mapping and VPL rendering. Interestingly, we did not observe any significant difference in user workflow for the different algorithms.