ACIS SAT
GISBox is a one-stop 3D GIS data editing, conversion and publishing platform that supports editing in multiple GIS formats such as OSGB/GEOTIFF/RVT, converting to 3DTiles/Terrain and publishing.
Introduction
ACIS SAT (Standard ACIS Text) is a 3D geometric information format mainly used for processing 3D city models and geospatial data. ACIS is a solid modeling kernel developed by Spatial (now Dassault Systèmes) in the United States, and SAT is the most commonly used text format file saving method in ACIS.
The ACIS SAT format is widely used in engineering modeling software such as BIM (Building Information Modeling) and CAD (Computer-Aided Design), and is suitable for multiple professional fields such as architecture, civil engineering, and mechanical design, with good cross-platform data interoperability.
File Structure
ACIS SAT file is a structured text format with the following features:
- The file extension is .sat
- The readable text format is human-friendly and easy to parse
- The file records structural information such as entities, bodies, faces, edges, and vertices
- The beginning of the file contains ACIS version information, which can be used to manage compatibility
- It can be imported and exported through common CAD or BIM software (such as AutoCAD, BricsCAD, FreeCAD, etc.)
Pros
- High-precision geometric expression: supports solid modeling, NURBS surfaces and Boolean operations, and can achieve engineering-level modeling accuracy
- **Good interoperability: **Many CAD/BIM software support SAT format, which facilitates data exchange between different platforms
- Text format is easy to process: Compared with binary format, it is easier to view, debug and analyze
- Stable and reliable format: ACIS has more than 30 years of industrial application history, mature format, and rich document support
Cons
- **Large file size: **Since it records high-precision geometric information and uses text format, the file size is usually large
- Not suitable for direct use by visualization engines: Poor compatibility with real-time 3D engines (such as Cesium or Three.js) and needs to be converted to a lightweight grid format
- Difficult to integrate with GIS systems: It does not contain geographic coordinate information, and format conversion and coordinate supplementation processing are required if it is to be linked with GIS
Application Scenario
ACIS SAT is mainly used in engineering application scenarios such as architectural design, civil engineering, manufacturing design processes, BIM/CAD modeling, structural analysis, and facility management due to its high-precision 3D modeling capabilities. In recent years, with the popularization of urban digitization and digital twin technology, SAT files have also been used as intermediate formats, and are converted into lightweight formats such as FBX, glTF, and 3D Tiles to reconstruct applications in GIS or 3D city visualization platforms. For example, using 3D data conversion tools such as GISBox, engineering data from ACIS SAT can be converted into a lightweight visualization format suitable for Web display, enabling its reuse and integration in smart cities, disaster simulation, facility inspection, and other fields.
Example
- 3D ACIS Modeler.

- SAT file opened in the software.

File Opening Mode
- This can be viewed using modules in structural modeling tools such as RFEM.

- Use the SAT Viewer to directly preview the structure of SAT files.

LYR
MID
MDB
QLR
References
- https://en.wikipedia.org/wiki/ACIS
- https://www.spatial.com/glossary/sat-file-type
- https://cadexchanger.com/blog/3d-formats-overview-acis/