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STL Converter


STL_Reader can read and STL_Writer can write STL (Stereolithography) files.

Both text and binary formats are supported.

The STL format describes a model with the help of individual triangles. Thus it does not allow to transfer any precise geometry, product structure, meta-data and even connectivity information.

Assemblies support

Given that the STL format does not allow to transfer product structure, it is inefficient for transfer of assemblies. Some systems write assemblies by producing a single flat list of triangles of all parts, some write a file as concatenation of individual files corresponding to parts.

In the former case, when importing, CAD Exchanger will create a single part, in the latter case - an assembly with respective number of parts.

When writing assemblies CAD Exchanger produces a flat list of triangles. Therefore it is recommended to export assemblies in per-part mode, creating a single file for each part.


Import Export
  • polygonal representations
  • polygonal representations


Importer Parameters

The STL import parameters are controlled by STL_ReaderParameters. The following table contains a list of parameters for STL import:

Parameter Default value Description
SetLengthUnit (Base_LengthUnit LengthUnit) Base_LU_Millimeters See Base_ReaderParameters::SetLengthUnit (Base_LengthUnit LengthUnit).

Exporter Parameters

The STL export parameters are controlled by STL_WriterParameters. The following table contains a list of parameters for STL export:

Parameter Default value Description
IsText() false Specifies whether a file must be written in text or binary format
LengthUnit() Base_LU_Millimeters See Base_WriterParameters::LengthUnit().
MultiPart() false Specifies if the file should be written using multipart approach. If true then the assembly is written as concatenation of individual STL files inside the resulting file. Otherwise an assembly is written as a continous set of triangles from all the parts.
PreferredLOD() ModelData_RM_Medium See Base_WriterParameters::PreferredLOD()