Curved Staircase Design & Cutlist

I’m building a free-standing curved staircase that turns 60° in plan, has six treads, a consistent 5-inch rise, and 8ft long on the lond side. The structure will be framed with Fir 2x4, surfaces will be 3/4" plywood, and side will be flexible plywood. I’ll be painting the finished assembly.

To move forward I need a complete, build-ready package based on a reference photo I’ll supply. The concept in the photo already looks workable, so please keep its overall aesthetic while making sure every dimension is structurally sound and code-conscious (International Residential Code or equivalent). Accuracy is critical because I’ll fabricate everything myself in a home workshop.

Deliverables
• Scaled drawings (PDF + editable CAD/SketchUp files) showing plan, elevation, section, and individual tread/stringer profiles
• Full material and cut list: lumber sizes/lengths, sheet-goods breakdown, recommended fasteners and hardware, and estimated quantities
• Assembly guidance: order of operations, jig suggestions for the curved stringers, and any lamination schedules if you choose a built-up stringer approach
• 3D model I can spin on screen to visualise the curve and verify clearances
• Quick note on surface prep so the painted finish bonds well

Acceptance Criteria
• All six steps rise exactly 5" with consistent tread depth
°stairs to be 36" wide
• 60° total turn measured at tread centreline
• Drawings align within 1" of stated dimensions
• Cut list matches drawing call-outs line by line

Preferred tools are AutoCAD, Fusion 360, SketchUp, or similar—you choose. If something in my brief leaves a gap, flag it early so we can decide together before you finalise the files.