Convert AD_PRT to STEP

A supplier, inspection system, CAM package, or other CAD application may require STEP instead of an Alibre part file. Exporting to STEP provides a broadly supported copy of the model for exchange, while retaining the original .AD_PRT file for future parametric editing.

What the AD_PRT format is

.AD_PRT is the native part format used by Alibre Design and compatible Alibre products such as Atom3D. It can contain a parametric solid, feature history, sketches, dimensions, constraints, configurations, and Alibre-specific design data. An .AD_PRT file normally represents one part; an Alibre assembly uses an .AD_ASM file and may reference multiple part files.

The extension cannot be changed manually to .STEP or .STP. The file must be opened by software that understands the Alibre format and then exported to a neutral CAD format.

What the STEP format is

STEP, commonly saved with the .step or .stp extension, is an ISO 10303 exchange format for transferring CAD geometry between mechanical-design, CAM, CAE, inspection, and manufacturing systems. It normally transfers exact boundary-representation solids and surfaces rather than a faceted mesh.

STEP does not carry the original Alibre feature tree or parametric editing model. The receiving system generally imports an unhistory-based, or “dumb,” solid. AP242 is preferable when both applications support it; AP214 remains widely used, and AP203 may provide compatibility with older systems. The available application protocols depend on the Alibre version and export dialog.

How to convert the file

Alibre Design or Atom3D is the preferred desktop method because it can interpret the native model and regenerate its features before export.

1. Open the source file in Alibre Design or a compatible Alibre product with File → Open.
2. Resolve missing references, suppressed features, and regeneration errors. A model that opens with failed features may export incomplete or invalid geometry.
3. Use File → Export and select STEP. In some releases, the command is available through File → Save As with STEP selected as the output type.
4. Select AP242 or AP214 if the export dialog provides that choice. Select the required units and export tolerance only when those settings are available and specified by the recipient.
5. Save the result with a .step or .stp extension, then open it in the target CAD system or an independent STEP-capable viewer.
6. Check the imported solid, overall dimensions, hole locations, wall thicknesses, curved surfaces, and modeled threads. Compare the result with the source before sending it for manufacture or inspection.

For an assembly, open the related .AD_ASM file and use Alibre’s assembly STEP export. Exporting one referenced .AD_PRT file does not reproduce the complete assembly or its component positions. If the recipient needs separate part files, export the components individually as well.

Desktop and online alternatives

Alibre software is the safest choice for preserving the source model’s final geometry. A current version of CAD Exchanger Desktop may be useful as an alternative only if its published input-format list explicitly includes Alibre .AD_PRT; format support and assembly handling can change between releases. Verify the converted result in a second CAD system rather than treating a successful upload or download as proof of correctness.

Online conversion is usually unsuitable for .AD_PRT because many browser services do not support this proprietary input format. A service such as CAD Exchanger Cloud should be considered only after its current format list confirms .AD_PRT support, its supported Alibre versions are clear, and uploading the design is permitted. Do not upload confidential or export-controlled CAD data to a converter without an approved data-processing policy.

Quality and compatibility limits

STEP normally loses sketches, feature order, editable dimensions, constraints, configurations, suppressed features, design intent, and Alibre-specific metadata. Cosmetic annotations such as non-modeled thread callouts may also be lost. A thread transfers as geometry only when the source contains an actual helical model rather than a cosmetic representation.

STEP includes unit information, but an importer can apply incorrect document defaults or scale the model incorrectly. Confirm the units and measure known dimensions after import. AP242 or AP214 support is not guaranteed by every older CAD, CAM, or inspection application.

If the target system imports separate faces or an open shell instead of a solid, use its heal, stitch, or sew tools and inspect the resulting volume. Re-export after repairing the source when possible; healing a damaged translation in the target system can hide gaps or change small features. Keep the original .AD_PRT file because STEP is an exchange copy, not a replacement for the native parametric model.