What is the SAT file format?
The .sat file format is used by the 3D ACIS Modeler software kernel, developed by Spatial Corporation (now part of Dassault Systèmes). .sat files store 3D geometry data in plain text format, making them a neutral exchange format for solid models built on the ACIS kernel.
.sat files are used for exchanging 3D data between various modeling environments, such as 3D animation software or software used in the shipping and aerospace industries. Geometry data is also used for non-sequential modeling of objects - for example, for modeling lighting systems or light scattering. .sat files are supported by many CAE, AEC, CAD, CMM and CAM software packages, provided they include an ACIS component.
.sat format stores data as ASCII text, i.e. as plain text. The file opens with a numeric version header on the first line (for example 400 0 1 0) followed by ACIS entity records; the file ends with an End-of-ACIS-data marker. Because .sat file structure is straightforward, the file may be viewed using any standard text editor, though meaningful interpretation requires ACIS-aware software. The MIME type is application/x-acis.
A binary version of the .sat format, called .sab, also exists and carries the same model data in a more compact form. For interoperability with other CAD ecosystems, .sat models are often converted to neutral formats such as STEP or IGES.
Security & safety
RISK: LOWA SAT file is plain ASCII geometry data - no executable code, so opening one is safe. The only real concerns are non-malicious: ACIS version mismatches can prevent import into older CAD, large models can be slow to load, and (because SAT carries exact geometry) sharing one may reveal more design detail than intended. As always, confirm a file's true type if a '.sat' arrived unexpectedly - only the container is harmless.
Format details
in a nutshellPrograms that open SAT files
Windows4 apps
CAD Assistant (Open Cascade)
Free Free offline viewer/converter; open the .sat (and .sab) to view, measure, and export (e.g. to STEP/STL/glTF). Best free desktop option.
Autodesk AutoCAD
Paid Use the ACISIN command (Insert > Import) to bring the SAT solid into the drawing. AutoCAD uses ACIS natively.
Autodesk Fusion 360
Freemium Upload/Insert the .sat to import the solid for editing. Free for personal/hobby use.
TurboCAD / IronCAD
Paid File > Import/Open the .sat; both are ACIS-based CAD that read SAT directly. 
macOS2 apps
CAD Assistant (Open Cascade)
Free Open the .sat to view and export; free cross-platform viewer/converter on macOS.
Autodesk Fusion 360
Freemium Insert/import the SAT for editing; free for personal use, native macOS app. 
Linux2 apps
FreeCAD (InventorLoader add-on)
Open-source Install the InventorLoader workbench, then import the .sat (SAT/SAB ACIS support). Free, though add-on quality varies by file.
ShareCAD
Free Upload the .sat in a browser to view and rotate the 3D model - no install. Supports SAT (ACIS). Technical details
deep spec| Encoding | Plain 7-bit ASCII text; readable in any text editor without special tools |
| File header | First line is a numeric version triple (e.g., `400 0 1 0`); encodes ACIS kernel version and entity record counts |
| End marker | Entity list is terminated by the literal string `End-of-ACIS-data` on its own line |
| Geometry kernel | ACIS solid-modeling kernel by Spatial Corporation (a Dassault Systèmes company) |
| Geometry representation | Boundary representation (B-rep): lumps, shells, faces, loops, edges, vertices and their topology |
| Entity indexing | Every geometric entity is assigned an integer index; entities cross-reference each other by index within the file |
| Binary counterpart | `.sab` (ACIS BinaryFile) stores identical model data in compact binary; identifiable by `ACIS BinaryFile` magic at file offset 0 |
| MIME type | `application/x-acis` |
| Version compatibility | Kernel version encoded in header; newer readers typically open older files, but older readers may reject newer-version files |
| Attribute support | Supports embedded attributes: transforms, colors, surface properties and application-defined metadata per entity |
| Topology support | Handles both manifold and non-manifold geometry; supports multi-lump assemblies in a single file |
| Typical use case | Neutral exchange between ACIS-based CAD/CAM/CAE tools including AutoCAD, Inventor, CATIA V5, Fusion 360 and IronCAD |
| File size range | Simple parts: a few kilobytes; complex assemblies with dense geometry can reach tens of megabytes |
| Released | Early 1990s (ACIS kernel by Spatial Technology; ACIS R1 1989) |
| Specification | www.spatial.com |
SAT conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about SAT files.
