Efficient hybrid volume and texture based clouds
Laura K. Murphy, Martin Sebastian Senn, Matthew Webb · 2018
We developed workflows for Cars 3 and Incredibles 2 that maintain most benefits of volumetric clouds while leveraging the render speed and artistic control of traditional texture based approaches. For Cars 3, we rendered volumetric clouds using Houdini and RIS to create layered, reference plates that matte painters used to quickly paint sky texture maps. The Houdini based workflow let us intuitively scout sequences and set up paintings. We detail artist-friendly tools in Photoshop to allow for intuitive composition adjustments. On Incredibles 2, we replaced the Photoshop portion of the pipeline with Nuke and rendered three passes: key, fill, and world position. Standardizing the workflow around world aligned, high resolution, hemispherical textures greatly streamlined the process and provided downstream lighting department with greater control integrating the sky with the foreground.