fixedcrest

Fixedcrest is a concept in computer graphics and computational geometry describing a ridge-like crest on a polygonal mesh that is preserved during smoothing and subdivision.

Definition and approach: A subset of edges (or sometimes vertices) is designated as fixed crests. These creases are intended to remain sharp as the surrounding texture is refined. During smoothing, the algorithm applies standard smoothing to unfixed areas while enforcing constraints at fixed crests, which can prevent the dihedral angle from collapsing toward flatness.

Implementation: Common techniques include constrained Laplacian smoothing, crease-aware subdivision, and anisotropic diffusion that preserves curvature along crest edges. In practice, fixedcrest may also be realized by assigning higher weights to fixed-crest edges or by introducing inequality constraints that preserve a minimum crease angle.

Relation to other concepts: It is related to the idea of crease edges in many 3D modeling tools; fixed crest is sometimes used interchangeably with crease-edge or feature-edge concepts, though usage varies by author.

Applications: Used in CAD, character and product modeling, film and game production, and any workflow requiring sharp silhouette or structural features to persist through smoothing steps.