Triangles are the available evidence
An STL stores triangular boundaries. It does not normally contain sketches, dimensions, hole features or the analytic cylinder that existed before tessellation. Changing the container cannot restore information that the original export discarded. This converter writes each triangle as a planar STEP face, so the represented boundary stays recognizable.
What can still be useful
A receiving CAD program may accept a faceted B-rep where it would not accept a mesh. You can inspect dimensions, place the part in an assembly, or use supported downstream operations. Capability varies by application and face count. A cylinder remains many small planes; it does not become a clean editable circular feature.
Prefer the original design when available
Ask the author for STEP or the native CAD file before attempting reconstruction. If only STL exists, retain the original and label the conversion as faceted. A reverse-engineering workflow is a separate task requiring fitted surfaces, tolerances and comparison with the mesh.
Try a known object before a complex part
Load the generated 20 mm cube example and run the check. Its twelve triangular faces enclose 8,000 cubic millimeters, and the reported bounding box is 20 × 20 × 20 mm. Download the STEP and open it in the intended receiving program. This small reference separates basic import compatibility from problems caused by a large or damaged model.
Next, choose your actual ASCII or binary STL, select its source units and run again. A selected file takes precedence over the cube option. Compare the preview with the original object, then read the topology findings before using the export. The input limit is 12 MB and 20,000 triangles.
Recognize a successful but unsuitable conversion
A faceted cylinder may import correctly yet be inconvenient for editing because its wall contains many planar faces. Increasing export size does not add missing curvature. If the next task requires changing a hole diameter or applying a precise fillet, obtain the original CAD or use a deliberate surface-fitting workflow instead. The normalized STL download is a useful comparison copy, not a recovered design history.