Sketcher BSplineComb

Show/hide B-spline control polygon

Show/hide B-spline knot multiplicity

Sketcher

Sketcher BSplineComb
Menu location
Sketch → Sketcher B-spline tools → Show/hide B-spline curvature comb
Workbenches
Sketcher
Default shortcut
None
Introduced in version
0.17
See also
Sketcher Create B-spline

Description

Shows or hides the display of the Curvature Comb of a B-spline (see this page for more info about B-splines).

The curvature comb indicates the curvature (value of the second-order derivative) of the B-spline at every position. The higher the curvature at a position, the more is the the comb away from the curve. For positive curvatures ("turn to the right"), the comb is at the other side of the curve than for negative curvatures.

B-spline with a saddle point at its mid position - the curvature comb there is zero.

Usage

1. Select a B-spline
2. Either use the toolbar button Show/hide B-spline curvature comb or use the menu Sketch → Sketcher B-spline tools → Show/hide B-spline curvature comb.

Show/hide B-spline control polygon

Show/hide B-spline knot multiplicity

Sketcher

Sketcher

• General: Create sketch, Edit sketch, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch, Leave sketch, View sketch, View section, Toggle grid, Toggle snap, Configure rendering order, Stop operation

---

• Sketcher geometries: Point, Line, Arc, Arc by 3 points, Circle, Circle by 3 points, Ellipse, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola, B-spline by control points, Periodic B-spline by control points, B-spline by knots, Periodic B-spline by knots, Polyline, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, Fillet, Corner-preserving fillet, Trim, Extend, Split, External geometry, Carbon copy, Toggle construction geometry

---

• Sketcher constraints:
  • Geometric constraints: Coincident, Point on object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal, Symmetric, Block
  • Dimensional constraints: Lock, Horizontal distance, Vertical distance, Distance, Radius or weight, Diameter, Auto radius/diameter, Angle, Refraction (Snell's law)
  • Constraint tools: Toggle driving/reference constraint, Activate/deactivate constraint

---

• Sketcher tools: Select unconstrained DoF, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide internal geometry, Select origin, Select horizontal axis, Select vertical axis, Symmetry, Clone, Copy, Move, Rectangular array, Remove axes alignment, Delete all geometry, Delete all constraints

---

• Sketcher B-spline tools: Show/hide B-spline degree, Show/hide B-spline control polygon, Show/hide B-spline curvature comb, Show/hide B-spline knot multiplicity, Show/hide B-spline control point weight, Convert geometry to B-spline, Increase B-spline degree, Decrease B-spline degree, Increase knot multiplicity, Decrease knot multiplicity, Insert knot, Join curves

---

• Sketcher virtual space: Switch virtual space

---

• Additional: Sketcher Dialog, Preferences, Sketcher scripting

User documentation

• Getting started
• Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
• Basics: About FreeCAD, Interface, Mouse navigation, Selection methods, Object name, Preferences, Workbenches, Document structure, Properties, Help FreeCAD, Donate

---

• Help: Tutorials, Video tutorials
• Workbenches: Std Base, Arch, Assembly, CAM, Draft, FEM, Inspection, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Start, Surface, TechDraw, Test Framework, Web

---

• Addons: Addon Manager, External workbenches, Scripting and macros

---

• Hubs: User hub, Power users hub, Developer hub