From CAD to Slicer: The Bridge

THE STANDARD EXPORT WORKFLOW:

STEP 1: VERIFY IN CAD
  Before exporting, verify:
    - Model is 'manifold' (no holes, no overlapping faces)
    - Dimensions are correct
    - Orientation is good for printing
    - No 'invisible' bodies or features hiding

  In Fusion: use the Inspect tool to check.
  In FreeCAD: use 'Tools > Check Geometry'.
  In OnShape: 'Show Features' to verify everything is there.

STEP 2: PICK EXPORT FORMAT
  STL: universal, the standard for 3D printing.
       Pro: every slicer accepts STL.
       Con: mesh-based; loses original CAD information.

  3MF: newer; better. Supports materials, colors, multi-body.
       Pro: more information than STL.
       Con: not every slicer fully supports.

  STEP: for sharing CAD source with other engineers.
        Pro: preserves all features.
        Con: not for slicing; just for collaboration.

  Recommendation: Use 3MF if your slicer supports it; otherwise STL.

STEP 3: EXPORT QUALITY
  STL exports have a resolution setting (faceting).
  Higher resolution: smoother curves, larger file size.
  Lower resolution: faster slice, visible polygons on curved surfaces.

  Fusion: 'High' or 'Custom' resolution. Custom: 0.001-0.01mm tolerance for fine prints.
  FreeCAD: in 'Mesh' workbench export options.
  OnShape: similar tolerance options.

  Default 'Medium' is fine for most prints.

STEP 4: VERIFY THE EXPORT
  Open the STL/3MF in your slicer.
  Look at the preview: does it match what you designed?
  Check the dimensions: should match CAD.
  Check for floating features or holes.

  Common export bugs:
    - One body is missing (forgot to include it)
    - One body is upside down
    - Internal 'voids' aren't represented
    - Curves are angular (resolution too low)

STEP 5: SLICE
  Apply your settings (LH, walls, etc.)
  Inspect the layer preview.
  Generate G-code.

ITERATING:
  If the print fails or the part doesn't fit:
    1. Open the STL in your slicer.
    2. Inspect the part.
    3. If the issue is in the model: fix in CAD; re-export.
    4. If the issue is in slicing: adjust slicer settings.

  Don't 'fix' the STL by editing it in a mesh editor. Always fix in CAD.

CAD-SPECIFIC GOTCHAS:

Fusion 360 STL export:
  - Auto-orients to 'Z is up' on export (verify this is what you want)
  - Some thin features may be lost (set 'High' quality)

OnShape STL export:
  - Excellent quality default
  - Supports color in 3MF format

FreeCAD STL export:
  - Quality varies by version
  - In version 1.0+, much improved

OpenSCAD STL export:
  - F6 to render; then File > Export > STL
  - Very fast for simple models

Blender STL export:
  - Triangulate first (Mesh > Triangulate)
  - Apply transforms (Object > Apply > All Transforms)
  - Then File > Export > STL