Convert STP to SAT

A receiving CAD or CAM application may accept only ACIS SAT files, so a supplier’s STEP model must be translated before editing or manufacturing. SAT can also provide a compatible exchange format for ACIS-based software when direct STEP import fails.

What the STP format is

STP and .step are filename extensions for STEP, the ISO 10303 neutral CAD format. STEP usually stores precise boundary-representation geometry and may also carry assembly structure, colors, layers, product data, and engineering metadata, depending on the STEP application protocol and exporting system.

CAD users receive STEP files from suppliers, export them between systems such as SolidWorks, Inventor, CATIA, Siemens NX, Fusion, and FreeCAD, or use them to archive geometry independently of the original CAD application. STEP is intended for broad interoperability rather than preservation of a specific program’s parametric history.

What the SAT format is

SAT is the text-based interchange format associated with the ACIS geometric modeling kernel. It stores ACIS boundary-representation data such as solids, shells, faces, trimmed surfaces, edges, and analytic geometry. ACIS-based applications, including AutoCAD and some engineering, CAM, simulation, and manufacturing systems, may require SAT or handle it more reliably than STEP.

SAT can preserve solid geometry well for downstream editing, but it is not a general replacement for STEP’s product-exchange data. Assembly relationships, colors, layers, attributes, PMI, and application-specific metadata may be simplified or lost. The related .sab format is a binary ACIS format; do not select it when the receiving application specifically requests text-based .sat.

How to convert STP to SAT

Using CAD Exchanger Desktop

1. Install CAD Exchanger Desktop from the official CAD Exchanger website and confirm that the installed edition supports SAT export.
2. Open the .stp or .step file with File → Open.
3. Check the model tree, units, body count, assembly structure, and visible geometry. Repair or suppress visibly defective imported bodies before exporting if the software provides those tools.
4. Choose File → Export, select ACIS SAT or .sat, choose the destination, and select any available assembly or product-structure options.
5. Open the exported file in the target program, confirm its scale and body structure, and run that program’s geometry check or repair command.

CAD Exchanger is a dedicated option when the original authoring CAD system is unavailable. Format availability and export settings can vary by product edition and release.

Using Autodesk software

In Autodesk Inventor, open the STEP file through File → Open, then use File → Save Copy As and select SAT when the exporter is available in that release. In AutoCAD releases that support STEP import, import the model, select the ACIS solids, and run ACISOUT to write them to a .sat file. Autodesk menus, command names, supported SAT versions, and assembly handling vary by product and release, so verify the target version’s documentation.

Using an online converter

CAD Exchanger Cloud provides browser-based STEP-to-SAT conversion when the service exposes SAT as an available output format. Upload the STEP file, choose SAT, start the conversion, and download the result. Check the service’s current format list and file-size limits before uploading.

Do not send proprietary, export-controlled, customer-confidential, or security-sensitive geometry to an online service unless organizational policy explicitly permits cloud processing. Use a desktop converter for restricted designs and retain the original STEP file as the source.

Quality and compatibility limits

• Parametric data does not normally transfer. Feature history, sketches, constraints, drawings, native materials, and CAD-specific design intent are generally reduced to non-parametric B-rep geometry.
• STEP assemblies may become separate SAT bodies, a flattened model, or separate output files, depending on the exporter. Confirm the required structure in the receiving application.
• Check units during import and export. A unit mismatch can produce a valid-looking model at the wrong scale.
• Inspect small fillets, threads, narrow gaps, sliver faces, and surface boundaries after translation. A model can look correct while containing open shells, self-intersections, or invalid solids.
• SAT files are ACIS-version dependent. If the target application rejects the result, export an older SAT version when the converter offers that setting, or use the target application’s SAT import options.
• Preserve the original STEP file and compare key dimensions, volumes, body counts, and assembly placement before using the converted model for manufacturing or analysis.