Using this tool

A walkthrough for a new estimator or drafter, plus a glossary of the building terms used throughout.

1. 3D Model

Set the building's geometry here: frame type (gable, multi-span, multi-gable, single slope, monitor, curved), width/length/eave, bay spacing, roof slope, and every option below it — mezzanine, openings, cladding, colours, crane, bracing, site background. Every other tab reads from these settings, so start here. The 3D view updates live; drag to orbit, scroll to zoom.

2. Drawings

The line-drawing sheets — side elevation, end elevation, cross section, floor plan, roof plan — generated straight from the 3D model, so they always match it. These feed into the Proposal automatically; you don't draft them separately.

3. Renders

Photorealistic views of the building for the client: isometric, rigid frame isometric (structure only, no cladding), side, end, aerial, plus dusk and landscaped-site treatments. These regenerate whenever the geometry changes.

4. Calibration

The weight/rate database behind the estimate — real jobs' actual tonnage, seeded in so a new building's estimate is grounded in what was really built, not just a formula. Internal use; not shown to the client.

5. Frame Check

A structural cross-check of the primary frame (rafter and column) against the stated loads — bending, shear, deflection, slenderness — with a moment/deflection diagram on the actual frame shape. It checks one representative interior bay, not a full indeterminate analysis; use it as a sanity check on the estimate's tonnage, not a stamped calculation.

6. Proposal

Assembles the full client (or internal) document: cover, design parameters, renders, elevations/plans, specification, pricing, terms & conditions. Three toggles change what prints:

Client / Internal — Internal adds the engineering take-off, BOM and design-criteria sheets that never go to the client.
Technical — the client proposal with the Contract Prices sheet replaced by design criteria, for technical approval before pricing. Export PDF names it “Proposal for Technical Approval”.
Estimation — turns the take-off into a fill-in sheet (an "Eng. qty" column) so a designed quantity can be typed in against the parametric budget once the real engineering is done.
Metric / Imperial — switches every dimension's display units; the underlying model stays metric.

Use Export PDF to print the Proposal. Export DXF exports the current building's geometry as a CAD file.

Where the numbers come from

Steel tonnage is a parametric estimate calibrated against real jobs (see Calibration), not a full structural design — the Frame Check tab is the closest thing to an engineering check this tool does. Cladding, insulation, accessories and freight are priced from the rate card for the selected factory/currency. Typing a number into a rate field (roof/wall sheeting, steel per kg, erection) overrides the catalogue rate for that field only — clear it back to 0 to return to the catalogue rate.

Glossary

Building terms as used in this tool and in PEB drafting generally.

Rigid frame: The main structural bent — two columns and a rafter (or two rafters meeting at a ridge) — repeated at every bay along the building's length.
Bay: The space between two adjacent rigid frames, measured along the building's length.
Eave: The line where the roof meets the sidewall — its height is the "eave height".
Ridge: The highest point of the roof, where the two roof slopes (or the single slope's high end) meet.
Knee: The corner joint where a column meets the rafter — usually the deepest, heaviest point of the frame.
Purlin: A secondary member spanning between rafters, across the roof slope, that the roof sheeting is fastened to.
Girt: A purlin's equivalent on the wall — spans between columns, carries the wall sheeting.
Base plate: The steel plate at the foot of a column, bolted to the concrete foundation via anchor bolts.
Built-up section: A welded I-shape (flange + web plates cut and welded, not rolled) — the standard PEB frame member, often tapered along its length to follow the bending demand.
Cold-formed section: A thin steel section (Z or C shape) roll-formed from sheet — used for purlins, girts and light secondary framing, not the main frame.
Gable: A roof with two slopes meeting at a central ridge; also the triangular wall at each end of that roof shape.
Multi-span: A building with one or more interior column lines, each adding another ridge/valley across the width — wider buildings than a single frame can economically span.
Multi-gable: Several gable modules side by side across the width, each with its own ridge — an alternative to multi-span for very wide buildings.

Roof monitor: A raised, narrower structure sitting on the main roof ridge (glazed or louvred) for daylight and ventilation — its own lighter frame, not a step in the main frame.
Jack beam: A beam spanning between frame lines at rafter level, carrying an interior column that skips alternate frames — reduces the interior column count.
Valley: Where two roof slopes meet and drain toward each other (the opposite of a ridge) — on a multi-span or multi-gable roof, valleys need their own gutter, since rainwater collects there.
Parapet: A wall extending above the roofline all the way around the building, hiding the roof slope from view at ground level.
Fascia: A flat trim panel at the eave, covering the end of the roof purlins without extending as high as a parapet.
Gutter / downspout: The gutter collects roof rainwater along the eave; downspouts (or "leaders") carry it down the wall to the ground, sized by roof catchment area.
X-bracing / portal bracing: The system that resists sideways (wind/seismic) loads along the building's length: X-bracing is diagonal cables (12.7 mm galvanised strand as standard — rods or angles where a compression diagonal is needed) in an "X"; portal bracing is a rigid moment frame instead, used where the bay must stay clear for a door.
Wind column: A column in the endwall that only carries wind load on the end wall — not part of a rigid frame, since the endwall usually isn't one.
Sandwich panel: A cladding panel with insulation foam bonded between two metal skins — insulation and cladding in one fixed panel, instead of separate sheeting plus a liner and loose insulation.
Liner panel: A metal sheet fixed to the inside face of the girts/purlins, giving the building a finished interior wall/ceiling and holding loose-fill insulation in place.
Out to out: A dimension measured to the outside face of the steel frame — the standard way a PEB's width and length are stated, as opposed to a centreline-to-centreline measurement.
Erection: The on-site assembly of the building. "Supply only" excludes it — the client's own contractor erects the delivered steel and panels.