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Vertex Curvature

In one sentence: Create a colour-map object showing surface curvature at every vertex of the mesh — blue for flat regions, red for sharp edges and corners.

Overview

Workbench: Mesh
Menu: Mesh → Meshes → Vertex Curvature
Command: Mesh_VertexCurvature
Shortcut: none

Creates a Mesh::Curvature object in the model tree that stores principal curvature values at every vertex. The mesh is displayed with a colour map indicating curvature variation across the surface.

Intuition

Curvature measures how sharply a surface bends. Flat faces have zero curvature; edges and corners have high curvature. The colour map makes it immediately obvious where a mesh has fine detail (red), smooth transitions (green), or flat regions (blue).

Vertex Curvature is also a prerequisite for Curvature Info, which lets you click a point to read the exact curvature value there.

When to use it

  • Identifying sharp features and corners in a scanned mesh.
  • Locating degenerate triangles (isolated red dots on a nominally flat face often indicate noise or bad topology).
  • As a prerequisite for Curvature Info to read numerical values at specific points.
  • Validating surface quality before reverse-engineering fit operations.

Step-by-step

  1. Select the mesh in the model tree.
  2. Choose Mesh → Meshes → Vertex Curvature.
  3. A Mesh::Curvature object appears in the tree.
  4. The mesh is now displayed with the curvature colour map.
  5. Use Curvature Info to click individual vertices for numerical readings.

Colour map reference

Colour Curvature meaning
Blue Low curvature (flat regions)
Green Moderate curvature
Red High curvature (sharp edges, corners)

Common mistakes and pitfalls

Isolated red dots on flat faces indicate noise

A flat face should show uniform blue. Isolated red spots usually indicate degenerate triangles, non-manifold points, or scan noise. Run Evaluate and Repair to fix the underlying topology issues.

Python API

import FreeCAD as App
import Mesh

doc = App.ActiveDocument
mesh = doc.getObject("Mesh")

curvature = doc.addObject("Mesh::Curvature", "MeshCurvature")
curvature.Source = mesh
doc.recompute()

See also