# Sketcher reference

## Introduction

User *chrisb* wrote a lengthy 70-page reference manual for the Sketcher Workbench that covers many topics of using this workbench. For inexperienced users, it is a gentle introduction that covers the basic usage of the Sketcher, and then goes into many details of creating geometrical elements, and using each type of constraint.

The manual is a work in progress, as some sections are reviewed and updated depending on the development occurring on the Sketcher Workbench. The original manual was written for FreeCAD 0.17, then it was updated for 0.18, and now for 0.19. The latest manual can be found in the forum thread, Sketcher tutorial.

Due to the evolving nature of the manual, the document is also known as the "Sketcher lecture".

Example sketch in the reference manual.

## Contents

The general structure of the manual is:

- Basics
- Create a sketch
- The Sketcher window
- General remarks on degrees of freedom
- Auto constraints

- Geometric elements
- Common usage
- Line
- Circle
- Arc
- Polyline
- Rectangle
- Polygon
- Slot
- B-splines
- Conical sections
- Construction geometry
- Point

- Constraints
- Selecting constraints
- Applying constraints
- The solver
- Coincidence
- Point on object
- Vertical
- Horizontal
- Parallel
- Perpendicular
- Tangency
- Equality
- Symmetry
- Block
- Lock
- Horizontal distance
- Vertical distance
- Length
- Radius and diameter
- Angle
- Dos and don'ts with constraints
- External geometry

- Creating objects based on sketches
*(to be written)*- Sketches for pads
- Symmetry
- Placement and attachment offset
- Validate sketches

**General:**Tutorials, Video tutorials (Product design, Architecture, Obsolete)

**Sketcher:**Basic Sketcher tutorial, Sketcher reference**PartDesign:**Simple object, Simple object 2, How to use FreeCAD PartDesign**Part:**Engraved text, Wiffle ball, Basic modeling, Screw threads, Placement**TechDraw:**Basic TechDraw tutorial, New template

**Path:**Path for the impatient**FEM:**Cantilever analysis, Electrostatic analysis, Shear in a composite block, Postprocessing with Paraview, Reinforced concrete**Rendering:**Raytracing tutorial, POV-ray, Blender

**General:**Create sketch, Edit sketch, Leave sketch, View sketch, View section, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch, 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, Periodic B-pline, Polyline, Rectangle, Centered rectangle, Rounded rectangle, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Regular polygon, Slot, 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, Diameter, Radiam, Angle, Snell's law, Internal alignment**Constraint tools:**Toggle driving/reference constraint, Activate/deactivate constraint

**Sketcher tools:**Select unconstrained DoF, Close shape, Connect edges, Select associated constraints, Select associated geometry, Select redundant constraints, Select conflicting constraints, Show/hide internal geometry, Select origin, Select vertical axis, Select horizontal 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

**Sketcher virtual space:**Switch virtual space

**Additional:**Sketcher Dialog, Preferences, Sketcher scripting

**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, Draft, FEM, Image, Inspection, Mesh, OpenSCAD, Part, PartDesign, Path, Points, Raytracing, Reverse Engineering, Sketcher, Spreadsheet, Start, Surface, TechDraw, Test Framework, Web**Deprecated or unmaintained workbenches:**Complete, Drawing, Robot

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