| .SAT | Spatial Corp | File di CAD | ACIS SAT 3D Model File | Autodesk Fusion 360 | Autodesk, Inc. |
| .SBP | Autodesk, Inc. | File con immagini raster | Sketchbook Express iCloud Image | SketchBook | Autodesk, Inc. |
| .SCH | Autodesk, Inc. | File di dati | EAGLE Schematics File | Autodesk EAGLE | Autodesk, Inc. |
| .SDC | Stardock Corporation | File backup | Stardock Central Download Archive | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .SDF | Microsoft Corporation | File di database | SQL Server Compact Database File | AutoCAD Map 3D | Autodesk, Inc. |
| .SDK | Autodesk, Inc. | File di CAD | AutoSketch Drawing | AutoSketch | Autodesk, Inc. |
| .SDL | Microsoft Corporation | File sviluppatore | Service Description Language File | Infrastructure Map Server | Autodesk, Inc. |
| .SET | Xerox | File di settaggi | Document Library Property Set File | Autodesk AutoCAD Ecscad | Autodesk, Inc. |
| .SHP | Autodesk, Inc. | File 3D | AutoCAD Shape File | Autodesk AutoCAD Ecscad | Autodesk, Inc. |
| .SHX | Autodesk, Inc. | File di CAD | AutoCAD Compiled Shape File | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .SI | Autodesk, Inc. | File 3D | Softimage Image File | Autodesk Softimage 2015 | Autodesk, Inc. |
| .SKF | Autodesk, Inc. | File di CAD | AutoSketch Drawing | AutoSketch | Autodesk, Inc. |
| .SKL | Autodesk, Inc. | File 3D | Maya Skeleton File | Autodesk Maya | Autodesk, Inc. |
| .SLB | Autodesk, Inc. | File vari | AutoCAD Slide Library | Autodesk AutoCAD | Autodesk, Inc. |
| .SLD | ESRI (Environmental Systems Research Institute) | File di GIS | Styled Layer Descriptor | Autodesk AutoCAD | Autodesk, Inc. |
| .SLDASM | Dassault Systèmes | File di CAD | SolidWorks Assembly File | Autodesk Fusion 360 | Autodesk, Inc. |
| .SLDPRT | Dassault Systèmes | File di CAD | SolidWorks CAD Part File | Autodesk Fusion 360 | Autodesk, Inc. |
| .SLG | Dionex Corporation | File di dati | Chromeleon Audit Trail Data | Autodesk AutoCAD | Autodesk, Inc. |
| .SLP | Magix Software GmbH | File audio | SpectraLayers Pro Project | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .SMB | Autodesk, Inc. | File di dati | Autodesk Symbol Library | Autodesk AutoCAD Ecscad | Autodesk, Inc. |
| .SQLITE | Dwayne Richard Hipp | File di database | SQLite Database File | AutoCAD Map 3D | Autodesk, Inc. |
| .SSC | Microsoft Corporation | File sviluppatore | SourceSafe Status File | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .STB | Autodesk, Inc. | File di settaggi | AutoCAD Plot Style Table File | Autodesk AutoCAD | Autodesk, Inc. |
| .STEP | Unknown Developer | File 3D | STEP 3D Model | Autodesk Fusion 360 | Autodesk, Inc. |
| .STP | Unknown Developer | File 3D | STEP 3D CAD File | Autodesk Fusion 360 | Autodesk, Inc. |
| .STYXML | Autodesk, Inc. | File di CAD | Inventor Style Library File | Autodesk Inventor | Autodesk, Inc. |
| .SV$ | Autodesk, Inc. | File backup | AutoCAD Automated Backup File | Autodesk AutoCAD | Autodesk, Inc. |
| .TBL | Blizzard Entertainment Inc. | File di dati | StarCraft Information Table | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .TBP | Trimble Inc. | File di CAD | Tekla BIMsight Project | Autodesk Topobase | Autodesk, Inc. |
| .TDF | DVD Copy | File di settaggi | Title Definition Format File | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .TF | Borland | File di settaggi | Turbo Profiler Configuration | Autodesk Inventor | Autodesk, Inc. |
| .TSK | Microsoft Corporation | File di settaggi | Pocket PC Skin | Autodesk EAGLE | Autodesk, Inc. |
| .UG | Autodesk, Inc. | File con immagini vettoriali | Drawing File | AutoCAD for Mac | Autodesk, Inc. |
| .UNT | Autodesk, Inc. | File di dati | AutoCAD Unit Definition Data File | Autodesk AutoCAD | Autodesk, Inc. |
| .USR | FileMaker Inc. | File di database | FileMaker Pro Database File | CadSoft EAGLE | Autodesk, Inc. |
| .UVW | Autodesk, Inc. | File di dati | UVW Coordinates File | Autodesk 3ds Max | Autodesk, Inc. |
| .VLX | Autodesk, Inc. | File eseguibili | Compiled AutoLISP File | Autodesk AutoCAD Ecscad | Autodesk, Inc. |
| .VRT | Superscape | File web | Virtual World | Autodesk AutoCAD | Autodesk, Inc. |
| .VUE | E-on Software, Inc. | File 3D | Vue Scene File | Autodesk 3ds Max | Autodesk, Inc. |
| .WAC | Wacom | File di dati | Inkling Sketch XML File | SketchBook | Autodesk, Inc. |
| .WDP | Microsoft Corporation | File con immagini raster | Windows Media Photo File | Autocad Electrical | Autodesk, Inc. |
| .WEA | Autodesk, Inc. | File di dati | Ecotect Weather File | Ecotect Analysis | Autodesk, Inc. |
| .WPI | Wacom | File con immagini vettoriali | Inkling Sketch Binary File | SketchBook | Autodesk, Inc. |
| .XLG | Autodesk, Inc. | File di dati | AutoCAD External Reference Log | Autodesk AutoCAD | Autodesk, Inc. |
| .XLO | Autodesk, Inc. | File di CAD | Autodesk Inventor Export Journal Data | Autodesk Inventor | Autodesk, Inc. |
| .XMS | Alexander Gross | File di settaggi | Music Studio Project | Autodesk AutoCAD | Autodesk, Inc. |
| .XMX | Autodesk, Inc. | File di dati | AutoCAD External Message Compiled Data | Autodesk AutoCAD | Autodesk, Inc. |
| .XSI | Autodesk, Inc. | File 3D | Softimage XSI 3D Image | Autodesk Softimage 2015 | Autodesk, Inc. |
| .XSP | Open Source | File audio | Kodi Smart Playlist File | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .XTP | adnx | File di dati | xTime Project Document | Autodesk AutoCAD Civil 3D | Autodesk, Inc. |
| .X_T | Siemens PLM Software | File di CAD | Parasolid Model Part File | Autodesk Fusion 360 | Autodesk, Inc. |
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