Free Online DSTV / NC1 File Viewer & Editor

NC1-Viewer.com is a free, browser-based viewer for DSTV .nc1 files — the CNC data format used throughout the structural steel industry. Open an NC1 file straight from your computer and instantly see the part in accurate 2D face views and interactive 3D, complete with holes, slots, copes, cuts, and markings. Nothing to install, no signup required, and your files never leave your device: all parsing and rendering happen locally in your browser.

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What is a DSTV (.nc1) file?

DSTV is a machine-neutral interchange format defined by the German Steel Construction Association (Deutscher Stahlbau-Verband) for describing individual structural steel parts to CNC machinery. Each plain-text .nc1 file describes one part: its profile (beam, channel, angle, plate, tube, and so on), material grade, overall dimensions, and the work to be done on it — drilled holes, external and internal contours, markings, and bends — organized into standardized blocks such as ST (part header), BO (holes), AK (outer contour), IK (inner contour), SI (numbering), and PU/KO (markings). Detailing software such as Tekla Structures and Autodesk Advance Steel exports NC1 files, which fabricators feed to beam drill lines, saws, and plasma or laser cutters. Read more in our guide, What is a DSTV NC1 file?

What you can do with NC1-Viewer

View parts in 2D and 3D — every DSTV face (web, top flange, bottom flange, behind) as a dimensioned 2D drawing, plus a full 3D model you can rotate, pan, and zoom.
Inspect holes and contours — hole diameters, slots, counterbores, positions per face, external copes and cuts, and internal openings.
Check header data — piece ID, order, phase, profile type and size, steel grade, length, and quantity parsed from the ST block.
Load multiple parts — drop in a whole batch of .nc1 files and switch between parts to review a delivery or export.
Edit and export (Pro) — correct hole positions and header fields, then export clean NC1 files back out.

How it works

Open nc1-viewer.com in any modern browser — desktop, laptop, or tablet.
Click Open file (or drag and drop) and choose one or more .nc1 / .nc files.
Review the part in 2D face views or 3D, hover holes for exact positions and diameters, and verify the header data before material hits the machine.

Who is it for?

Steel detailers double-checking an export before sending it to the shop; fabricators and CNC operators verifying incoming NC1 files without booting a full CAD seat; estimators and project managers who just need to see a part; and engineering students learning how CNC data for structural steel actually works.

Frequently asked questions

Is it really free? Yes — viewing NC1 files is free with no account. A Pro subscription adds editing and export features.

Are my files uploaded to a server? No. Files are parsed and rendered entirely in your browser. See our Privacy Policy.

Which profiles are supported? I-sections, channels, angles, plates, round and rectangular hollow sections, T-sections, and more. See DSTV profile types for the full list.

More questions and answers on the FAQ page.