# How to View STEP PMI and GD&T Online

Open a STEP AP242 part, show its saved dimensions, geometric tolerances and datums, and check which PMI survived the CAD handoff.

If a supplier sends a STEP file with a note that says “use the model tolerances,” check the callouts before quoting. A hole can measure 35 mm and still have a separate size tolerance, position tolerance or datum requirement. The geometry gives you a nominal shape. Product and manufacturing information (PMI) carries the engineering instructions that were actually saved.

## Open the original PMI

1. Upload the original STEP AP242 part in the [CADProps workspace](https://www.cadprops.com/workspace?mode=view).
2. Once the 3D model opens, choose **Source PMI** in the toolbar. The model can appear while the server is still checking its PMI.
3. Turn on **Show PMI on model** and choose a source view when one is available. Use **All source PMI** to see the callouts together. Select a callout in the list to center it.
4. Compare a critical dimension, its tolerance and its datum against the released file or drawing. Use the graphical callout to read symbols and modifiers. Where CADProps can read structured values, the list also shows them.

<figure class="workflow-evidence"><img src="/assets/evidence/seo-2026-11-10-pmi/source-pmi-1440.webp" alt="NIST STEP AP242 part in the CADProps viewer with source callouts and the MBD_0 saved view selected" width="1440" height="810" loading="lazy"><figcaption>CADProps viewing a public NIST CTC-01 STEP AP242 sample. MBD_0 is the view stored in the original file.</figcaption></figure>

## What the public sample shows

Use `nist_ctc_01_asme1_ap242-e1.stp` from the [NIST PMI STEP files archive](https://www.nist.gov/document/nist-pmi-step-files). The file supplies 23 graphical callouts in its MBD_0 view, including a 60° angle and datum labels A, B and C. A second public sample, `nist_ctc_03_asme1_ap242-e2.stp`, supplies 29 graphical callouts. NIST provides the [model definitions and reference sheets](https://www.nist.gov/ctl/smart-connected-systems-division/smart-connected-manufacturing-systems-group/mbe-pmi-0) so you can repeat the comparison.

A graphical callout describes what a person can see. Semantic PMI contains structured information a CAD or inspection system can interpret. One can exist without the other. Read the source callout and keep the original CAD file for the controlled manufacturing definition.

## Check what was available from your file

| What the panel reports | What to check |
| --- | --- |
| Callouts and a source view | Check the critical callouts, datum labels and their positions against the source. |
| No source PMI found | Confirm the exporter published the annotation views. An AP242 header alone does not mean PMI is present. |
| Source PMI could not be verified | Use the original CAD application or request a new AP242 single-part export with graphical PMI. The model preview remains available. |

The panel opens the source callouts when CADProps can verify their graphical coverage. Read the value and units on the callout itself. For SolidWorks, CATIA, Inventor or NX files, export the part as STEP AP242 with graphical PMI in the source CAD application. Use **Annotations** to add separate CADProps review notes.

For offline review of eligible STEP files, follow the [3D PDF export guide](https://www.cadprops.com/guides/export-3d-pdf-with-pmi/index.md).

## Related reading

- [Does a STEP File Contain Tolerances and GD&T?](https://www.cadprops.com/guides/does-step-file-contain-tolerances/index.md)
- [How to Export a Rotatable 3D PDF With PMI](https://www.cadprops.com/guides/export-3d-pdf-with-pmi/index.md)
- [IAM Missing Parts? Fix Autodesk Inventor Assembly References](https://www.cadprops.com/guides/iam-missing-parts/index.md)
- [Open CAD Files on Mac: STEP Viewers and Format Options](https://www.cadprops.com/guides/open-cad-files-on-mac/index.md)
- [How to Open an IAM File Without Autodesk Inventor](https://www.cadprops.com/guides/open-iam-without-inventor/index.md)
- [How to Open an IPT File Online Without Inventor](https://www.cadprops.com/guides/open-ipt-without-inventor/index.md)
- [SolidWorks STEP Export Missing Components? Check Selection, Suppression & Assembly State](https://www.cadprops.com/guides/solidworks-step-export-missing-components/index.md)
- [STEP AP203 vs AP214 vs AP242: Which Protocol to Export](https://www.cadprops.com/guides/step-ap203-ap214-ap242/index.md)
- [Why STEP Files Lose the SolidWorks Feature Tree](https://www.cadprops.com/guides/step-export-no-feature-tree/index.md)

Original article: https://www.cadprops.com/guides/view-cad-pmi-online/

HTML page: https://www.cadprops.com/guides/view-cad-pmi-online/