Native CAD interfaces
Direct support for the CAD formats listed here.
Creo Viewer
Open PRT and ASM files
intuitive & practical 3D without CAD expertise
affordable & universal many 3D/2D interfaces
Modern, easy-to-use CAD viewer
Cost-effective CAD converter for all formats
The 3D-Tool Viewer opens Creo PRT and ASM files without Creo software.
The 3D-NativeCAD Converter converts Creo models to a wide range of formats such as STEP, IGES, JT, SAT, Parasolid X_T, STL, OBJ, 3D-PDF, 3D-HTML, FBX, 3MF, and glTF.
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Stable, precise CAD data processing.
Windows support
Compatible with current Windows versions.
Use Creo Models Without a Creo License
Anyone who receives a PRT or ASM model from Creo Parametric or its predecessor Pro/ENGINEER does not need a Creo license just to look at it. The 3D-Tool Viewer opens these files, shows the assembly structure and geometry, and allows direct measurements on the model.
This matters beyond design teams: purchasing, quality assurance, or customers regularly check supplier parts the same way, without buying an extra CAD license. For handing models to other systems, the 3D-NativeCAD Converter turns Creo models into STEP and other common exchange formats.
What are PRT and ASM files?
- PRT and ASM files from Creo Parametric are native 3D models.
- PRT is the part file format and contains 3D geometry and, in some cases, Product Manufacturing Information (PMI).
- ASM is the assembly file format. An ASM file is linked to at least one, but usually several, PRT files and often other ASM files.
- Several programs use the PRT file extension. In the CAD/CAM field, these are Creo Parametric and Designcenter (Siemens NX). The ASM file extension is used in CAD/CAM by Creo Parametric and Designcenter Solid Edge. Creo files can often be identified by a number after the file extension, for example *.prt.1, *.prt.2, *.asm.1, or *.asm.2.
Creo Versions
Creo Parametric is the successor to Pro/ENGINEER. Pro/ENGINEER was the first parametric 3D CAD system in 1988. From 2002 to 2008 it was called Pro/ENGINEER Wildfire. Creo Parametric has been part of the Creo suite since 2009. Older Creo versions generally cannot open PRT and ASM files from newer Creo Parametric versions. Files explicitly exported for an older Creo version are an exception.
Creo Elements is another application in the Creo suite. It is a direct modeling software application and a further development of CoCreate. Creo Elements has its own native file formats.
Creo View is a family of viewers for visualizing Creo 3D models and 2D drawings.
Additional native Creo file formats
- xpr, xas Optional accelerator files for part variants (xpr) and assembly variants (xas). They improve performance. However, some applications need them to display variants correctly.
- drw Native 2D drawing from Creo Parametric
- pvs, pvz Creo View files containing product visualizations from the PTC Creo Viewer.
- bdl Creo Elements bundle file containing a 3D model and related drawings.
- pkg Creo Elements archive, a compressed file made up of parts, assemblies, drawings, and workplanes.
How do I open Creo PRT and ASM files?
Open Creo PRT and ASM files with a Creo installation, CAD/CAM software with a Creo interface, or a CAD viewer. The free Creo View Express supports native Creo Parametric parts (prt) and assemblies (asm). However, it does not offer markup capabilities and provides only simple distance and length measurements.
In addition to PRT and ASM files, the 3D-Tool CAD Viewer opens many other CAD formats and offers extensive measurement and analysis functions.
How do I convert Creo PRT and ASM files?
Without CAD software with a Creo interface, the models must be exported from Creo to a common 3D exchange format, such as STEP.
Converting Creo ASM and PRT to STEP is also possible with a 3D converter.
The 3D-NativeCAD Converter in 3D-Tool Premium converts native Creo models and models from many other CAD systems reliably into the standard 3D exchange formats STEP, IGES, SAT, and Parasolid X_T.
Test the Creo viewer and Creo converter for free
3D-Tool is a CAD Viewer with many native CAD interfaces, including Creo. 3D-Tool provides professional measurement tools, draft analysis, and wall thickness analysis.
- Open PRT and ASM files, add dimensions and comments, and publish them for the 3D-Tool Free Viewer or as 3D PDF
- Open PRT and ASM files and save them as STL, 3DS, PLY, WRL, or OBJ
- Convert PRT and ASM files to STEP, IGES, SAT, X_T, and JT
- Convert Creo models to 3D product visualizations such as 3D-HTML, FBX, 3MF, and glTF
The 14-day trial is free and non-binding. It includes all features, the Creo interfaces, and the 3D-NativeCAD Converter. The trial key activates all 3D interfaces, including Designcenter (Siemens NX), SolidWorks, Inventor, STEP, SAT, and Parasolid.
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Frequently Asked Questions (FAQ)
What is the difference between Creo PRT and ASM files?
PRT is the part format of Creo Parametric and contains 3D geometry and, in some cases, PMI. ASM is the assembly format, linked to at least one PRT file and often further ASM files. A complete assembly therefore depends on the referenced files. When sending an ASM model to another user, include its parts and subassemblies so the assembly can be loaded in full.
How do I distinguish Creo PRT files from Designcenter (NX) PRT files?
Creo files are often marked by a number after the file extension, such as *.prt.1 or *.prt.2. Designcenter (Siemens NX) PRT files do not carry this suffix. Both systems use PRT, so the extension alone is not enough to identify the format. If the origin remains unclear, ask the sender which CAD system was used to create the file.
How can I open Creo PRT and ASM files without Creo?
3D-Tool opens native Creo Parametric parts and assemblies without a Creo installation. The viewer provides measurement and analysis tools for inspecting supplied models. A free 14-day trial includes the native CAD interfaces and the 3D-NativeCAD Converter, so you can try your own files with the required measurement and conversion tasks.
Are Creo Elements files the same as Creo Parametric files?
No. Creo Elements/Direct is a direct-modeling application developed from CoCreate and uses its own native formats, such as BDL and PKG. Creo Parametric uses PRT for parts and ASM for assemblies. When exchanging models, specify the application and file format so the recipient can select a suitable import interface.
Which formats can Creo files be converted to?
The 3D-NativeCAD Converter in 3D-Tool Premium converts native Creo PRT and ASM models reliably into STEP, IGES, SAT, and Parasolid X_T, plus visualization formats such as STL, OBJ, 3DS, PLY, 3D-PDF, 3D-HTML, FBX, 3MF, and glTF. Choose the target format according to whether the recipient needs exact CAD geometry or a model for visualization and presentation.