additive vs subtractive processes printing constraints materials ABS, HIPS, acrylic, PLA resolution time cost supports post-processing wall and edge thickness clearances orientation fills processes stereolithography fused-deposition molding extrusion contour crafting ink-jet binder ProJet PolyJet cut sheets selective laser sintering CLIP two photon digital machines RepRap Ultimaker MakerBot Sindoh Formlabs MTM service bureaus Shapeways Ponoko Additively file formats STL ASCII solid object_name facet normal n1 n2 n3 outer loop vertex v11 v12 v13 vertex v21 v22 v23 vertex v31 v32 v33 endloop endfacet ... endsolid object_name binary 80 byte ASCII header 32-bit integer number of facets 50 byte facet records 32-bit IEEE floats normal vertices 1,2,3 2 byte attribute right hand rule normal (optional) (lack of) units PLY AMF 3MF OBJ, 3ds,DXFVRML, X3D FREP, BREP adaptively-sampled distance fields volumetric .vol, .tiff, .gif marching cubes fab modules vol_gif gif_stl gif_png software 123D SketchUp Fusion 360 SolidWorks Rhino Grasshopper Blender FreeCAD OpenSCAD Antimony VTK MeshLab netfabb meshmixer Geomagic ReplicatorG Skeinforge Slic3r Cura Sketchfab scanning point cloud, triangulation, watertight, texture tomography Radon transform micro-CT scanned probe confocal serial sections opacity digitizer laser lidar array illumination time of flight photogrammetry 123D Catch PhotoScan VisualSFM speckle OpenKinect ReconstructMe Sense structured light laser pico-projector light stages SLAM assignment * test the design rules for your printer(s) (group project) * design and 3D print an object (small, few cm) that could not be made subtractively * 3D scan an object (and optionally print it) (extra credit: make your own scanner)