# JT File Tools: Solid Viewer and STEP Conversion

Open JT files that contain readable solid geometry, check dimensions, and convert those solids to STEP. Mesh-only JT is not validated.

JT is used for visualization, supplier review and, in some files, precise solid geometry. A `.jt` extension does not say which of those you received. CADProps opens JT when the file has **readable solid geometry**, and can write STEP from those solids. Tessellation-only JT is not validated. PMI and the original feature tree are not reproduced.

## Open a JT solid

Start with the [JT solid viewer](https://www.cadprops.com/tools/jt-viewer/index.md). Keep the original file unchanged. After processing, confirm the body count and one known dimension. A checked sample retained one solid and its 40 × 30 × 20 mm size through STEP conversion and an independent read-back. That does not validate every JT version.

If the file is rejected, do not rename it. Ask whether the sender exported precise B-Rep or only a lightweight mesh, and which JT profile they used.

## Measure and convert

Properties describe the loaded solid geometry. Volume requires a valid closed solid. Mass requires a density you choose. Use the viewer's STEP output when the next CAD system wants a neutral solid, then check the STEP again in the [STEP viewer](https://www.cadprops.com/tools/step-viewer/index.md).

Read [JT vs STEP](https://www.cadprops.com/guides/jt-vs-step/index.md) before you decide which file to send a supplier. [Open a JT file online](https://www.cadprops.com/guides/open-jt-file-online/index.md) is the step-by-step check.

## What this hub does not include

There is no separate promise for mesh-only JT, for full PLM product structure, or for turning JT into an editable native model. Large-assembly review in a dedicated JT workflow can still be the right process when the contract requires JT. This site is the solid-geometry inspection and STEP handoff.

See the [format matrix](https://www.cadprops.com/supported-formats/index.md) for neighbouring formats such as STEP and Parasolid.

HTML page: https://www.cadprops.com/jt/