Native CAD interfaces
Direct support for the CAD formats listed here.
SolidWorks Viewer
Open SLDPRT and SLDASM files
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The 3D-Tool Viewer opens SolidWorks SLDPRT and SLDASM files without SolidWorks software.
The 3D-NativeCAD Converter converts SolidWorks models to a wide range of formats such as STEP, IGES, JT, SAT, Parasolid X_T, STL, OBJ, 3DS, PLY, 3D-PDF, 3D-HTML, FBX, 3MF, and glTF.
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Windows support
Compatible with current Windows versions.
What are SLDPRT and SLDASM files?
- Files with the SLDPRT and SLDASM file extensions are native 3D files from SolidWorks CAD/CAM software.
- SLDPRT is the part file format and contains one or more 3D geometries and, in some cases, Product Manufacturing Information (PMI).
- SLDASM is the assembly file format and is linked to at least one, but usually several, SLDPRT files and often other SLDASM files.
- SolidWorks is aimed primarily at small and medium-sized mechanical engineering companies. From the beginning, the focus was on simple, user-friendly operation.
SLDPRT and SLDASM versions
New SolidWorks releases with numerous new features appear every year. Releases use the year as their version designation. The current version is SolidWorks 2026. (05/2026)
File versions created with newer releases cannot be opened with older releases. Starting with SolidWorks 2024, models can be saved back by up to two versions. The design must not contain features that are not yet available in the older version, or those features must be suppressed before saving.
In 1995, SolidWorks was the most affordable and easiest-to-use 3D CAD system, both in terms of operation and hardware requirements.
Additional native SolidWorks file formats
- slddrw Native 2D drawing from SolidWorks, derived from a SolidWorks 3D model
- slddrt SolidWorks template file. Contains drawing sheet templates for creating 2D drawings
- The Parasolid modeling kernel used by the software is also worth mentioning. Parasolid X_T and X_B files are history-free 3D exchange formats and the preferred choice for exchanging 3D models between CAD/CAM programs with a Parasolid kernel, such as Siemens NX, SolidWorks, and Solid Edge.
Which program opens SolidWorks SLDPRT and SLDASM files?
Typically, a SolidWorks installation is used for this. Alternatively, the files can also be opened with CAD/CAM software that has a SolidWorks interface.
The free eDrawings supports native SolidWorks parts, assemblies and drawings and offers simple markup and measurement functions.
The 3D-Tool CAD viewer also opens SLDPRT and SLDASM files, but provides extensive measurement and analysis tools. 3D-Tool can be tested free of charge for 14 days.
How do I convert SolidWorks SLDPRT and SLDASM files?
Without CAD software with a SolidWorks interface, the design must be exported from SolidWorks to a common 3D exchange format, for example STEP. For exchange with Siemens NX and Solid Edge, Parasolid X_T or X_B is recommended.
Converting SLDASM and SLDPRT to STEP is also possible with a 3D converter.
The 3D-NativeCAD Converter in 3D-Tool Premium reliably converts native SolidWorks models and models from many other CAD systems to common 3D exchange formats such as STEP, IGES, SAT, and Parasolid X_T.
Test the SolidWorks Viewer and SolidWorks Converter for free
3D-Tool is a CAD Viewer with many native CAD interfaces, including SolidWorks, as well as professional measurement tools, draft analysis, and wall thickness analysis.
- Open SLDPRT and SLDASM files, add dimensions and comments, and publish them for the 3D-Tool Free Viewer or as 3D PDF
- Open SLDPRT and SLDASM files and save them as STL, 3DS, PLY, WRL, or OBJ
- Convert SLDPRT and SLDASM files to STEP, IGES, SAT, X_T, and JT
- Convert SolidWorks models to 3D product visualizations such as 3D-HTML, FBX, Collada, 3MF, and glTF
Free, no-obligation 14-day trial with all features, the SolidWorks interfaces, and the 3D-NativeCAD Converter. The trial key activates all 3D interfaces, including Siemens NX, CATIA, Inventor, STEP, SAT, and Parasolid.
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