06 | End-to-End 3D Printing Emmett Lalish | Mechanical Engineer Kris Iverson | Lead Software Design Engineer

What is a Slicer? Slices 3D model into planar polygons Fills polygons with toolpaths Exports toolpaths as Gcode

Slicing is as much Art as Science Infinitely many paths exist to construct any single 3D model Best methods address physical hardware: Exploit strengths Hide weaknesses

Software Can Make Up for Hardware Small objects get too hot and slump Slow down on small areas to aid cooling Extruder drools when stopped Retract filament before traveling Small arcs cause too much acceleration Reduce speed based on radius of curvature

Why is Slicing so Hard? Common models have 105 – 106 faces Model Parsing Support Generation Common models have 105 – 106 faces Nonlinear transformations Floating-point rounding errors 3D -> 2D Slice Perimeter Inset Surface Detection Infill Travel Optimization Gcode Export

Manifoldness Does the mesh represent a solid? Every edge much share exactly two faces Those two faces must be oriented consistently

STL Ambiguities STL is currently the most common format for 3D models 30 year-old open standard Mesh topology is lost in STL Each face is stored separately Reconstructing the manifold requires merging vertices with tolerance to account for rounding

3MF Format 3D Manufacturing Format Compressed XML Topological mesh storage Manifoldness required Support for colors, textures, materials Metadata, thumbnail Support for DRM Extensible