BIM, IFC models and shop drawings

What the service covers

Detailing turns a design into instructions for the shop and the site. World Steel models every building in 3D, produces drawings and CNC data from the model, and exports an open IFC model so that owners, architects and contractors can check the steel in their own BIM tools. The service is part of the design solution. Steps:

1. Model the structure from the approved design: members, plates, bolts, holes and welds.
2. Clash and constructability checks, including coordination with architectural or MEP models supplied by the client.
3. Generate approval drawings and, after approval, shop drawings (assembly and single-part) and erection drawings.
4. Export NC data (for example DSTV format) to CNC cutting, drilling and roll-forming machines.
5. Export IFC (ISO 16739-1) and, on request, native or PDF formats, with piece marks matching the physical parts.

Inputs needed from the client

• Approved design drawings and calculations, or WSC design.
• Architectural grid, levels and any reference models (IFC preferred).
• Required level of detail and model property sets (for example piece mark, weight, profile, grade, finish).
• Drawing standards, title blocks, units and language requirements.
• Review process and turnaround times for comments.

Deliverables

Models can be viewed on the World Steel portfolio site in the 3D viewer, the same way the building on the anatomy of a PEB page is shown.

Quality and compliance

Drawings are checked by a second detailer before release, and every revision is tracked in a drawing register. Detailing conventions follow the market: AISC detailing practice and US customary or metric units for the United States, CISC practice for Canada, AS/NZS 5131 documentation requirements for Australia and New Zealand, and EN 1090-2 execution specification requirements for Germany, the United Kingdom and the rest of Europe. Piece marks, weld symbols (AWS A2.4 or ISO 2553) and bolt designations follow the code of the job. See design deliverables.

Using the IFC model

An IFC model is most useful when it is shared early. Owners and architects use it to check clear heights, door and crane clearances and roof drainage; MEP designers use it to route ducts and pipes around rafters and bracing; and contractors use it to plan cranes and lifts. Because each member carries its piece mark, weight and grade, the model also supports logistics planning and site receipt. The model shows the steel as fabricated, so the agreed revision should be used for coordination, and any change requested after release of shop drawings goes back through the drawing register and the design check.

Envelope and accessories in the model. Structural members are modelled piece by piece, while the envelope is usually represented in a lighter way that still supports coordination and quantity take-off:

See design deliverables, roof sheeting and trims and flashings for how these items are documented.

Typical schedule

Typically, approval drawings for a single-storey PEB are issued about 1–3 weeks after order, and shop drawings about 1–3 weeks after approval, overlapping with material procurement. Large or highly coordinated BIM projects take longer, and review turnaround by the client affects the programme. These ranges are indicative.