What is "surfel"

Surfel \Sur"fel\, Surfle \Sur"fle\, v. t. [Cf. Sulphur.] To wash, as the face, with a cosmetic water, said by some to be prepared from the sulphur. [Obs.]

She shall no oftener powder her hair, [or] surfel her cheeks, . . . but she shall as often gaze on my picture.
--Ford.

Etymology 1 alt. (context obsolete transitive English) To wash with a cosmetic water, said by some to be prepared from sulphur. vb. (context obsolete transitive English) To wash with a cosmetic water, said by some to be prepared from sulphur. Etymology 2

n. (context computer graphics English) A unit square between voxels.

Surfel is an abbreviation of "surface element". In 3D computer graphics, the use of surfels is an alternative to polygonal modeling. An object is represented by a dense set of points or viewer-facing discs holding lighting information. Surfels are well suited to modeling dynamic geometry, because there is no need to compute topology information such as adjacency lists. Common applications are medical scanner data representation, real time rendering of particle systems, and more generally, rendering surfaces of volumetric data by first extracting the isosurface.