I’m building a modern-style web application that guides users from file upload through to visualised engineering results. Core workflow • Authenticated Admin, Editor, and Viewer roles sign in, then access a dashboard. • Users upload PDF or AutoCAD drawings. Your code must parse each file, detect objects, pull their dimensional data, and let the user confirm or edit the properties that the parser suggests. • Confirmed parameters are pushed to a back-end calculation engine via API. • Returned results appear instantly as interactive graphs and data tables, with options to download the raw numbers or a formatted PDF/CSV report. User should be able to format the graphs. Key requirements • Clean, responsive UI that matches a modern aesthetic. • Role-based access control screens for Admin, Editor, and Viewer. • Fully integrated payments: Credit/Debit Card, PayPal, and Bank Transfer. Subscription logic (monthly / annual) lives in Stripe or an equivalent gateway you recommend. • Robust PDF extraction—accuracy is critical, so please outline your chosen library (e.g., pdf.js, PyPDF2, PDF-Plumber, etc.) and how you’ll handle edge cases such as rotated or scaled drawings. • Results visualisation with a lightweight charting solution (Chart.js, D3, or similar) that exports cleanly to PNG and PDF. Acceptance criteria 1. Upload a sample PDF, confirm object data, trigger calculation, and receive matching results in both chart and table form. 2. Role restrictions verified: Viewer has read-only, Editor can upload/edit, Admin manages plans and billing. 3. Payment flow completes a live $0.01 test transaction for each supported method. Let me know your preferred tech stack, estimated timeline, and any past work parsing technical PDFs so we can align quickly and start.