Study guide

This module is curated — the teaching is a top free course (linked in the card above); our job is to point you at the right things, make you understand the ideas that matter, and certify you.

FreeCAD is free and open-source, so there is nothing to buy and nothing to expire — you can install it today and follow along on the same software the course uses.

The plan

1. Watch the course (the card above — MangoJelly's Basic Beginners FreeCAD v1 Course). You don't need to memorise every click; aim to understand the ideas below and reproduce them once yourself.
2. Install FreeCAD 1.x from freecad.org and model along. The single best way to learn CAD is to build a part while you watch.
3. Focus on these — they are what the K-Check tests and what the technical viva (S-Check) will push on:
   • The Part Design workbench — the beginner-friendly, feature-based way to model a single solid. You work inside a Body, and you build it up one feature at a time: Pad (extrude a sketch into a solid), Pocket (cut a sketch shape out), plus revolve, fillet and chamfer.
   • Sketching + constraints — every solid feature starts from a 2D sketch on a plane or face. Geometric constraints (coincident, horizontal, vertical, parallel, perpendicular, tangent, symmetric, equal) capture design intent; dimensional constraints (length, radius, angle) set the numbers. Your goal on every sketch is fully constrained — no white/under-defined geometry left that can drift.
   • The parametric model tree — the tree on the left records every sketch and feature in order, and the part is recomputed from it. Change a dimension or an earlier feature and the whole part rebuilds. This history is what makes the model parametric and editable later.
   • Basic part modelling — take a real object, break it into a base shape plus a few pads/pockets/fillets, and reproduce it. That decomposition skill is the whole game.
4. Take the K-Check (10 questions) and then the S-Check (a short technical viva with a senior engineer) to earn your certificate.

The FreeCAD mental model — why it feels different

A parametric CAD model is not a drawing; it is a recipe. You are not pushing pixels into a final shape — you are recording an ordered list of steps (sketch a rectangle, pad it 20 mm, sketch a circle on the top, pocket it 5 mm, fillet these edges) that FreeCAD replays to produce the solid. Edit any step and it re-runs the recipe. Two habits follow directly from this and separate people who fight CAD from people who drive it: keep every sketch fully constrained, and keep every feature referenced to stable geometry. The next slide is about the second habit — and FreeCAD's single most famous pitfall.

Fully-constrained sketches, and why they matter

When you draw a sketch, FreeCAD shows under-defined geometry in white — it still has degrees of freedom and can slide around unpredictably when you edit later. Add geometric constraints (coincident, horizontal, parallel, symmetric…) and dimensions until the sketch turns fully constrained (it stops being white and the solver reports "Fully constrained"). A fully-constrained sketch has exactly one shape for its numbers, so when you change a dimension the part changes the way you meant — nothing floats. Getting into the habit of fully constraining every sketch is the highest-leverage thing a beginner can do.

The parametric model tree

Everything you make lands in the model tree: the Body, each sketch, each Pad/Pocket/Fillet, and any datum planes. The solid is computed by replaying that tree top to bottom. Because of this you can:

• double-click any sketch or feature to edit it and the part rebuilds,
• drive dimensions from parameters — put key values in a Spreadsheet and reference them (e.g. Spreadsheet.wall) so one edit updates every feature that uses it,
• reorder or insert features to change how the part is built.

This is what "parametric" means: the design is a set of driving values and steps, not a frozen mesh.

The famous topological naming problem (TNP) — and how to model robustly

FreeCAD's most notorious pitfall. When you sketch on, or reference, a face or edge of an existing feature, FreeCAD remembers it by an internal name like Face6 or Edge12. If you later edit an earlier feature, the geometry gets re-generated and those internal names can shift — so Face6 is now a different face. Your later sketch or fillet suddenly attaches to the wrong place, and the model breaks or deforms. That is the topological naming problem: references made to derived geometry are not stable across edits.

FreeCAD 1.0 added a mitigation that makes this far less painful than in older versions, but the robust-modelling habits still matter and the viva will expect them:

• Sketch on datum planes and the origin planes, not on model faces, wherever you can — datums don't get renamed when features change.
• Reference stable geometry — the base planes/axes and early, unchanging features — rather than the faces/edges of features you are likely to edit later.
• Use datum planes/points as robust anchors for later sketches and features.
• Keep the tree tidy and shallow: fewer dependencies on derived geometry means fewer things that can break.
• Model so that changing an early dimension only resizes the part — it should never leave references dangling.

Do this and your part stays editable and robust: you can hand someone a "wall = 3 mm, height = 40 mm" set of parameters and they can resize it safely months later.

Quick self-check

You want a later pocket to stay attached correctly even after you resize the base pad. Where should you place the sketch for that pocket? — On a datum plane (or an origin plane) referenced to stable geometry, rather than directly on a face of the base pad. Sketching on the pad's face is exactly what invites the topological naming problem to break the reference when the pad changes. If that reasoning is clear, you are ready for the K-Check and the viva.