#Sketcher

A good sketch gives your model a clear structure. You can control geometry with numbers rather than dragging shapes by eye, which helps keep designs consistent. This is especially useful when you need repeated parts, matching dimensions, or later revisions.

Sketcher is commonly used for mechanical parts, simple enclosures, profiles, and other objects that need accurate edges and clean proportions. It is also a useful way to learn parametric thinking: one sketch can drive many later features.

Main elements of a sketch

A sketch usually contains basic geometry and constraints.

• Geometry: lines, rectangles, circles, arcs, and splines
• Constraints: rules that define size, angle, distance, symmetry, coincidence, and tangency
• Reference geometry: construction lines or points that help organize the sketch without becoming part of the final shape

Beginners often start with simple closed profiles such as rectangles, circles, or combinations of straight segments and arcs. Closed profiles are important because they can often be used directly for 3D operations.

How constraints work

Constraints are what make Sketcher powerful. A line can be horizontal, vertical, fixed in length, or joined to another line at a point. A circle can have a defined radius and a set position. Two elements can be made equal, parallel, perpendicular, or symmetric.

The main idea is to avoid overcomplicating the sketch. Use only the constraints needed to define the shape clearly. Too few constraints can leave the sketch underdefined, while too many can make it harder to edit and understand.

Practical tips for beginners

Start with a simple shape and build up gradually. It is often easier to draw the rough outline first, then add constraints and dimensions.

• Keep sketches clean and readable
• Use construction geometry to guide placement
• Fully constrain important shapes when possible
• Check that the sketch is not overconstrained
• Break complex parts into several sketches if needed

If a sketch becomes difficult to manage, simplify it. Separate unrelated features into different sketches rather than trying to force everything into one drawing.

Common uses and good habits

FreeCAD Sketcher is most useful when you treat it as the base of a design, not just a drawing area. Think in terms of relationships: what must stay centered, what must stay equal, and what size matters most. This makes later changes much easier.

A careful sketch often saves time later. If you build a model on a stable 2D foundation, the rest of the design tends to be more predictable, easier to edit, and less likely to fail when dimensions change.