# 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, Shear in a composite block, Postprocessing with Paraview, Reinforced concrete**Rendering:**Raytracing tutorial, POV-ray, Blender

**The tools:**New sketch, Edit sketch, Leave sketch, View sketch, View section, Map sketch to face, Reorient sketch, Validate sketch, Merge sketches, Mirror sketch

**Sketcher geometries:**Point, Line by 2 point,**Create an arc,**Arc, Arc by 3 Point,**Create a circle**, Circle, Circle by 3 Point,**Create a conic**, Ellipse by center, Ellipse by 3 points, Arc of ellipse, Arc of hyperbola, Arc of parabola,**Create a B-spline**, Create B-spline, Create periodic B-pline, Polyline (multiple-point line), Rectangle,**Create regular polygon**, Triangle, Square, Pentagon, Hexagon, Heptagon, Octagon, Create Regular Polygon, Slot, Fillet, Trimming, Extend, External Geometry, CarbonCopy, Construction Mode

**Sketcher constraints****Geometric constraints**Coincident, Point On Object, Vertical, Horizontal, Parallel, Perpendicular, Tangent, Equal Length, Symmetric, Constrain Block**Dimensional constraints**Lock, Horizontal Distance, Vertical Distance, Distance, Radius, Internal Angle, Snell's Law, Internal Alignment, Toggle reference/driving constraint,

**Sketcher tools**Select solver DOFs, Close Shape, Connect Edges, Select Constraints, Select Origin, Select Vertical Axis, Select Horizontal Axis, Select Redundant Constraints, Select Conflicting Constraints, Select Elements Associated with constraints, Show/Hide internal geometry, Symmetry, Clone, Copy, Move, Rectangular Array, 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, Convert Geometry to B-spline, Increase degree, Increase knot multiplicity, Decrease knot multiplicity

**Sketcher virtual space**Switch Virtual Space

**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