Volumetric Cloud Rendering: An Animation of Clouds

This paper demonstrates a production workflow for a volumetric-rendering-based short animation about clouds. The animation is based on the concept of a giant fish swimming in the sky from Zhuangzi\u27s philosophical story. The algorithm and implementation for the modeling and rendering of clouds are also presented. A renderer was developed that uses the OpenVDB library for data storage, fast retrieving and grid manipulation. A user-friendly pipeline was also developed for cloud modeling and rendering, which used Python and XML for adjusting rendering parameters. The pipeline includes Maya to build the rough cloud model and Houdini to calculate the interior light points. Final compositing was done in Nuke. Several MEL and Python scripts were also used to retrieve camera and light information from Maya and Houdini, thereby facilitating the production process