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What is a SAT file?

A SAT file is the ASCII (text) representation of ACIS model data. It stores the definition of a 3D model in a form that can be read, written, and exchanged by software that supports ACIS-based geometry.

SAT is usually contrasted with SAB, the binary form of the same underlying model data. The difference is not the geometry itself but the encoding: SAT is text-based and easier to inspect, while SAB is binary and more compact.

Format Encoding Typical strength
SAT ASCII (text) Human-readable, easy to inspect
SAB Binary More compact file size

What kind of data does it contain?

A SAT file can hold exact 3D model information, including:

  • solid bodies
  • sheet bodies and surfaces
  • topology relationships between faces, edges, and vertices
  • curves and analytic geometry
  • modeling attributes associated with the ACIS representation

Because it stores exact model data rather than a tessellated mesh, SAT is better suited to engineering reuse than formats meant mainly for viewing or 3D printing.

How does it work in CAD workflows?

In a typical workflow, a CAD system exports exact model geometry from its internal representation into SAT so another ACIS-compatible or SAT-capable system can reconstruct the model. This makes SAT useful when the goal is to preserve editable or queryable geometry as accurately as possible.

This differs from mesh-based formats such as STL, where the model is reduced to triangles. A SAT file keeps the model much closer to its original exact geometric definition.

SAT vs. other CAD exchange formats

SAT is often used for exact geometry exchange, but it is not a neutral standard in the same sense as STEP. It is closely tied to the ACIS modeling ecosystem.

Comparison How they differ
SAT vs. STL SAT stores exact geometry; STL stores a triangle mesh
SAT vs. STEP/STP STEP is a broader neutral exchange standard; SAT is tied more directly to ACIS geometry
SAT vs. DWG/DXF DWG and DXF are broader drafting and design formats; SAT focuses specifically on 3D model geometry

Applications and Industry Use Cases

SAT files are commonly used in CAD applications that need to exchange exact 3D solids and surfaces across platforms. Typical use cases include:

  • transferring part and body geometry between CAD systems
  • preserving precise solid models for downstream design work
  • passing geometry into simulation or manufacturing preparation workflows
  • supporting interoperability in applications built on or around ACIS-compatible modeling logic

They are especially relevant in mechanical design and engineering software, where exact B-rep geometry matters more than lightweight display alone.

Challenges or Common Pitfalls

Pitfall What to keep in mind
Treating SAT as a universal neutral CAD format It is widely useful but still closely tied to ACIS-based geometry, so support depends on the receiving application.
Assuming successful import means perfect reuse Issues can still arise from version differences, unsupported entities, tolerance handling, or application-specific interpretation.
Confusing SAT with lightweight 3D formats SAT is not meant for fast web visualization or 3D printing. It fits best when preserving precise geometry is the priority.

How Spatial Helps

SAT is native to our 3D ACIS Modeler ecosystem, so this format sits right in the middle of what we do. If you are building a CAD or engineering application, our modeling and interoperability tools let you create, read, modify, and exchange exact 3D model data in ACIS workflows.

Two of our SDKs apply here, depending on what you need:

  • 3D ACIS Modeler — use this when your application needs native solid and surface modeling built on ACIS geometry.
  • 3D InterOp — use this when SAT data has to be imported, exported, translated, or reused alongside other CAD formats in broader interoperability workflows.

Want to try it on your own SAT files? Request an evaluation or talk to our team.