8 lessons · about 114 minutes of reading · Onshape
Design things you can actually print
A course in parametric CAD for people who own a 3D printer and are tired of downloading someone else’s nearly-right model. You will finish able to measure a real object, model a part around it, and print something that fits on the first or second try.
Before lesson one
Get an Onshape free account. It runs in the browser, there is nothing to install, and it is fully parametric — which is the thing you are actually here to learn. The free plan makes your documents public, so keep anything confidential out of it.
Everything you learn transfers. Fusion 360, SolidWorks, FreeCAD and Onshape differ in menus, not in ideas — sketches, constraints, features and a history tree are the same everywhere.
Lessons
Work through them in order. Each one ends with a short recall check — answer it from memory, not by scrolling back. That discomfort is the part that makes it stick.
- 01The model is a recipe, not a shapeWhy parametric CAD stores the steps that build a part rather than the part itself — and your first solid in Onshape.12 min
- 02Sketches, constraints, degrees of freedomEvery sketch is a little puzzle with a countdown. Learn to drive it to zero so your geometry stops wandering.15 min
- 03Turning sketches into solidsExtrude, revolve, sweep, loft — and the boolean question every feature quietly asks you.14 min
- 04Design intent and a feature tree that survivesWhy models break when you edit them, and the referencing habits that stop it happening.14 min
- 05Variables: modelling the thing, not the numbersDrive a model from named variables so one edit resizes the whole part correctly.13 min
- 06Designing for the printer you actually ownOrientation, the 45° rule, bridges, wall thickness — the constraints that decide whether a part prints.16 min
- 07Tolerances, clearances, and the fit test couponWhy your holes come out small, and the twenty-minute calibration that ends the guessing.15 min
- 08From caliper to printed partMeasuring real objects, checking fit in an assembly, and exporting cleanly to your slicer.15 min
Keep these open while you model
FDM design rules
Every number this course uses — overhangs, walls, holes, clearances — on one printable page.
Glossary
The words CAD tutorials use without defining. Fixed meanings, used consistently across every lesson here.
How to actually get good at this
- Model along, don’t read along. Every lesson has a hands-on block. Reading CAD is like reading about swimming.
- Space it out. Two lessons a week beats eight in a day. Coming back to a half-forgotten model is where retention is built.
- Print the failures. A part that comes out wrong teaches more than three that come out right. Keep them on the shelf.
- Ask your teaching agent. These pages are a scaffold. The conversation is where your specific stuck-ness gets unstuck.
Sources for every claim in this course are listed on the resources page.