From Tekla model to workshop: the files that actually drive fabrication

A steel detailing model earns its keep when it leaves the screen. What the fabricator actually runs the workshop on is a set of outputs generated from that model, and the quality of the job depends on those outputs being complete, consistent and issued together.

The files behind the steel

• NC files (DSTV): the cutting, drilling and marking instructions that feed CNC beam lines, one file per part.
• DXF plate profiles: flat geometry for plasma, oxy-fuel or laser cutting of plates, fittings and stiffeners.
• Assembly and single-part drawings: what the fitters and welders build from, with weld symbols, dimensions and marks.
• Material and bolt lists: the buying and nesting information, often exported straight into the fabricator's management system.
• General arrangement and erection drawings: how the marked pieces go together on site.
• IFC and 3D views: a coordination model for the other trades, and a reference for the site team.

One model, many outputs: one revision

Because every one of these outputs comes from the same model, a change to the model has to flow to all of them at once. The classic workshop error isn't a bad model; it's a revised drawing issued alongside an old NC file, or a bolt list that missed the last change. The cure is discipline: revise the model, regenerate every affected output, and issue the set together with a clear revision record.

It's also why the connection design and the detailing belong close together. When the connection checked in the calculation is the same object that generates the NC file, there's nothing to translate. We wrote about that in who designs the steel connections.

What to agree at the start

• Which NC format and settings the fabricator's machines expect.
• How parts and assemblies are marked, so the marks on the steel match the paperwork.
• Which lists the fabricator imports, and in what format.
• How revisions are issued and recorded: per drawing, per package, or both.

Half an hour on these at kick-off saves days of re-issuing later. It's the least glamorous part of detailing and one of the most valuable.