Efficient slicing of Catmull–Clark solids for 3D printed objects with functionally graded material

•Catmull–Clark solids as representation for functionally graded material objects.•Fast algorithm for directly slicing Catmull–Clark solids for additive manufacturing.•Computational time is competitive to state of the art on trivariate trimmed splines. [Display omitted] In the competition for the volumetric representation most suitable for functionally graded materials in additively manufactured (AM) objects, volumetric subdivision schemes, such as Catmull–Clark (CC) solids, are widely neglected. Although they show appealing properties, efficient implementations of some fundamental algorithms are still missing. In this paper, we present a fast algorithm for direct slicing of CC-solids generating bitmaps printable by multi-material AM machines. Our method optimizes runtime by exploiting constant time limit evaluation and other structural characteristics of CC-solids. We compare our algorithm with the state of the art in trivariate trimmed spline representations and show that our algorithm has similar runtime behavior as slicing trivariate splines, fully supporting the benefits of CC-solids.