This scene is the pool scene used for Figure 7 in "Multidimensional Adaptive Sampling and Reconstruction for Ray Tracing" by Hachisuka et al. SIGGRAPH 2008.

Permission to use the model/scene for non-commercial purposes is granted as long as proper credit is given. For example, put "The pool scene in Figure X is from Hackisuka et al. [2008]" in the acknowledgement section of your paper.