Tinkercad

It is free with no paid tier at all, and yes, you can sell your own designs. Autodesk's terms let you keep ownership of what you create from the basic shapes and permit selling either the files or the printed objects. Two limits apply: you cannot resell Autodesk's own supplied assets from the shape gallery, and if you publish a design publicly to the gallery you grant Autodesk and every other user a worldwide royalty-free licence to use and remix it. Keep a design private if that matters.

No, and it cannot import them either. STEP, IGES and native CAD formats are unsupported in both directions, and attempting to upload one fails. Export is aimed at 3D printing and laser cutting: STL and OBJ for printing, SVG for the cross-section at the workplane, plus GLTF and 3MF, with USDZ on the iPad app. If someone needs a STEP file from you, the model has to go through Fusion or another solid CAD system first.

Use the built-in Send to Fusion bridge rather than exporting an STL, because an STL arrives as a faceted mesh that is painful to turn back into editable geometry. The bridge has a published limit, stated above the button itself: only basic shapes and groups of basic shapes will transfer. Autodesk's support documentation adds that a model too complex for the conversion fails with no message or reason given, and specifically suggests removing text before trying again.

Because STL has no way to store colour. Export as OBJ or 3MF instead, both of which keep the colours you applied. There is a related change worth knowing about: until September 2025 Tinkercad forced a boolean union on export so everything arrived as a single watertight shell. It now exports grouped objects as separate bodies when no hole subtractions are involved, which is what lets a multi-colour slicer assign a different filament to each part.

It is built for that case more deliberately than anything else in this directory. Under-13s cannot create unmoderated accounts; signup with a minor's birthdate requires a parent's email for authorisation. Through Tinkercad Classrooms a teacher issues a class code or link and students join with nicknames, supplying no email address at all, while the teacher can reset passwords, see every design and delete data on request. Student work is private by default. Autodesk states compliance with COPPA, FERPA and GDPR, sells no user data and permits no third-party advertising in the workspace.

When you need a dimension you can go back and change, parts that mate into an assembly, a curved or bevelled surface, or a STEP file for a supplier. None of those are limitations you can work around with skill, because the model has no parametric history and the geometry is built by adding and subtracting blocks. The other signal is performance: once a design has enough objects and hole subtractions to make the browser lag, it is also too complex to cross the Fusion bridge cleanly.

Two separate workspaces alongside the 3D editor. Codeblocks generates geometry from a visual program using loops, variables and conditionals, so the model is the output of code rather than of dragging shapes. Circuits is a breadboard simulator with an Arduino emulator, so a class can wire and run a circuit without hardware. Both are free with the same account, and for schools the fact that one login covers modelling, programming and electronics is a large part of the appeal.