AD_PRT File

What are AD_PRT files and how to open them

Are you having problems opening an AD_PRT file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your AD_PRT files.

What is an AD_PRT file?

An .AD_PRT file is an Alibre Design Part file.

Alibre Design Part is a native file format used by Alibre Inc.'s Alibre Design CAD software to store individual 3D parts. These files hold fully editable models created through features, sketches, and constraints, enabling designers to build precise components which can be modified at any time. The format includes the complete shape of the part as a solid object, its construction history (how it was built via operations like extrude, cut, fillet, revolve, etc.), and any parameter-driven or equation-driven dimensions.

Alibre Design writes .AD_PRT files. When using Alibre Design (Professional, Expert, Atom3D, etc.), every time you save a part you've been working on, you get an .AD_PRT file. Others cannot reliably edit these files using non-Alibre tools though exchanges are often done by exporting neutral formats (such as STEP or Parasolid) for use in other CAD systems or for manufacturing.

Technically, .AD_PRT is proprietary and not fully documented for public developers. Internally these part files contain a STEP/ISO 10303-21 data stream embedded alongside Alibre's own metadata and structure. One identifier is the file beginning with the signature D0CF11E0A1B11AE100 at byte offset 0, followed by content strings such as END-ISO-10303-21 and keywords like FILE_SCHEMA, PRODUCT_DEFINITION, DESIGNPART, APPLICATION_CONTEXT, ORIGINATING_SYSTEM, etc., that signal the embedded STEP content.

How to open AD_PRT files

Important: Different programs may use files with the AD_PRT file extension for different purposes, so unless you are sure which format your AD_PRT file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different AD_PRT openers which you will find listed below.

Last updated: August 17, 2026

Various apps that use files with this extension

These apps are known to open certain types of AD_PRT files. Remember, different programs may use AD_PRT files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about AD_PRT file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.