ACIS SAT

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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.