3D Printer FYISoftware is a tool for a geometry type. A phone mount wants parametric CAD. A miniature wants a sculptor. A downloaded STL that will not slice wants a mesh repairer.
Choose by model type, not by “best software”
| You are making | Typical class | Examples to evaluate |
|---|---|---|
| Brackets, boxes, Gridfinity-compatible bins | Parametric CAD | Fusion, Onshape, FreeCAD, SolidWorks |
| One-off organic enclosure | Direct / push-pull | Fusion, Plasticity, SketchUp (with care) |
| Creature / figurine | Sculpt | Blender, Nomad |
| Classroom first model | Browser / block | Tinkercad, SelfCAD |
| Scripted mechanical | Code CAD | OpenSCAD, CadQuery |
| Broken STL | Mesh tools | PrusaSlicer repair, MeshLab, Blender |
Always export a format your slicer likes (STL/3MF) and keep the editable source.
Parametric/mechanical CAD
Change a hole diameter without wrecking the part. Sketches + features (pad/pocket/fillet) are the job. If you will revise the same bracket for a year, this is the class.
FreeCAD. Start in Part Design: body → sketch → pad. The wiki is the manual. Do not mix Part and Part Design bodies until you know why they exist.
Onshape. Browser CAD with real versioning. The current Free plan is non-commercial; Onshape’s own help says Free documents are public (viewable and copyable). Do not put a client part on Free. Education plans exist — read the live pricing page, not a 2019 blog.
Fusion (personal use). Autodesk’s Fusion for personal use is a limited hobby build: home-based, non-commercial, not for primary employment or commercial training, and (on that page) limited to individuals generating less than $1,000 USD a year. It is a 3-year personal-use term in Autodesk’s current FAQ on that same page. CAM, drawings, and some export types are restricted versus a paid seat. Those terms change — open the official page before you build a shop on it.
Paid Fusion / SolidWorks / Inventor are fine when work pays for them. Do not pirate a seat and call it a workflow.
Direct modeling
Push-pull faces when the part is a one-off shell: an enclosure that will never get a second revision, a mock-up you will throw away. Fusion can do this; so can tools that never record a feature tree.
The cost is six months later: there is no “change the wall to 3 mm” parameter. If you might reprint it, you wanted parametric.
Sculpting/organic models
Blender (blender.org) is free and deep. Enable the bundled 3D-Print Toolbox and run its checks (non-manifold, intersections, thin walls) before export. Learn “manifold + wall thickness” or the slicer will punish you.
Nomad and similar tablet sculptors are the same geometry class: great clay, bad hole-with-tolerance. Retopo or rebuild mechanical bits in CAD.
Beginner/browser tools
Tinkercad is enough for classroom first prints: blocks, holes, a name tag, a simple case. Autodesk account, browser, no install. Age bands, queue rules, and when to move to Onshape are on that classroom page. Do not stay in Tinkercad for a gearbox.
SelfCAD and similar classroom suites exist; pick one the school can actually log into.
Open-source tools
FreeCAD, OpenSCAD (openscad.org), Blender, MeshLab. Pair with Git if you care about versions (open-source map).
OpenSCAD (and CadQuery) win when the part is a family: 20 bin sizes, one script. They lose when you need a sculpted grip.
Mesh repair and editing
If the slicer reports non-manifold edges, repair before you scale. PrusaSlicer/Orca have repair; MeshLab and Blender’s 3D-Print Toolbox exist when that fails.
Scaling a broken mesh just scales the holes in the surface. Fix, then size.
File formats: STL vs 3MF vs STEP and why it matters
| Format | What it holds | Use it when |
|---|---|---|
| STL | triangles only | a slicer that will not take 3MF |
| 3MF | meshes + more metadata, often multiple bodies | handing a print job to a modern slicer |
| STEP / IGES | CAD solids | you will edit later or send to a machine shop |
| Blend / FCStd / F3D | native | your project file — keep this |
STL cannot store a hole diameter. If you only archive STL, you cannot change the hole.
Export checks before slicing
- Units are millimeters (not leftover inches).
- The mesh is manifold; repair if the slicer says so.
- Wall thickness ≥ your nozzle width × 2 (or whatever your slicer preview shows as solid).
- Separate bodies for multi-material are actually separate.
- A 20 mm coupon before a 10-hour job.
Learning-path recommendations
- Need a bracket this weekend: Tinkercad or a Fusion/Onshape tutorial that ends in a 3MF, then stop.
- Need revisions for a year: parametric (FreeCAD or commercial CAD) + git.
- Need a figurine: Blender + the 3D-Print Toolbox, then mesh repair.
- Need classroom accounts: Tinkercad and the classroom guide.
- Need code: OpenSCAD examples, then a Gridfinity-compatible script from a repo you can read.
- Need private client CAD in a browser: not Onshape Free — read Onshape plans.
Do not collect five CAD packages. Collect one finished part.
Sources
- FreeCAD
- FreeCAD wiki — Part Design
- Blender
- Blender manual — 3D-Print Toolbox
- OpenSCAD
- Tinkercad
- Autodesk Fusion for personal use (terms change; this is the page to re-read)
- Onshape plans and pricing
- Onshape help — managing subscriptions
- OrcaSlicer wiki