APC TakeoffA drawing-to-estimate workspace for APC Construction, connecting AI-assisted takeoff, drawing evidence, estimator review, and Excel delivery in one workflow.
Explore the live productConstruction takeoff means turning a drawing set into material quantities. The information is spread across plans, elevations, schedules, and detail sheets. A member can appear in several views; a dimension can be incomplete; a referenced sheet can be missing. Moving the result into a spreadsheet does not resolve those uncertainties.
The challenge was to make automation useful to an estimator: show where a quantity came from, expose the assumptions used to calculate it, and keep unresolved work visible. APC Takeoff brings the drawing, the calculation, and the review decision into the same workspace.
I built the platform end to end: the estimating workspace, authenticated project and document flows, FastAPI services, drawing-processing pipelines, AI-assisted extraction, source-evidence views, review decisions, versioned takeoff rules, and Excel exports. My work connected the product interface to the workers, storage, and data model behind it.
Projects organize the source package before takeoff begins. Uploaded PDFs become classified sheets, with document progress and review status kept alongside the project. Estimators can return to a drawing, inspect its sheets, and see which rule profile is attached to the work.
The steel review queue connects a member’s count, length, and weight to the drawing region that supports it. Source selectors let the estimator move between relevant views, while measurement notes and warnings explain what still needs attention. Accept, Override, and Investigate provide explicit review paths, with notes and history preserving the context of a correction.
The AI drawing takeoff adds a broader path for reading a drawing set. Its concrete view distinguishes drawing-verified values from estimator-accepted ones and keeps lines needing review separate. It shows neat volume, waste-adjusted volume, formwork, and rebar allowances under the selected rules. Missing dimensions stay visible as missing; they do not silently become zero or a guessed total.
Opening a takeoff line reveals the source for individual dimensions and designations. The interface pairs the extracted text with a highlighted drawing crop, sheet number, page, and row reference. An estimator can inspect the footing schedule or elevation note that supports a value without hunting through the entire PDF.
Concrete rule profiles define waste, formwork treatment, top finish, and rebar planning rates by element type. Steel profiles control grouping, drawing priority, and size corrections. Editing produces a new version, and each takeoff retains the rules it used. This keeps a later profile change from rewriting the explanation of an earlier result.
Document processing, AI interpretation, deterministic calculations, and human review work together. Each layer has a distinct job, and the source drawing remains visible throughout.
A unified interface for projects, drawing sheets, takeoff results, source evidence, review decisions, and rule profiles. The review experience carries the context needed to judge each line.
The API records projects, document state, extraction runs, issue notes, decisions, and rule versions. Review history and the rules used by a run stay attached to the result.
PDF text rows and coordinates become addressable evidence. AI interprets drawing content; code checks cited values and computes quantities. Image-based refinement provides a second look for ambiguous content while unresolved inputs remain visible.
Separate workers lease queued jobs, report heartbeats, and recover stalled work. Private object storage holds PDFs and rendered sheets behind expiring URLs. Excel exports carry quantities, review information, evidence, and the concrete rule context.
A plausible reading is not enough to justify a quantity. Interpretation and arithmetic are separate stages, with source checks between them. This makes the path from cited dimensions to the calculated result inspectable.
Missing dimensions, unclear scope, and conflicting evidence need a review path. The interface preserves held lines and issue notes instead of making a drawing set appear complete. Provisional estimating treatment is distinct from accepting a quantity.
Versioned profiles and a saved rule snapshot make the calculation explainable later. Rebar planning rates and waste allowances are explicit inputs; they do not change the dimensions read from the drawing.
The delivered pilot connects drawing intake, steel and AI-assisted takeoff, source inspection, estimator decisions, and workbook delivery. It gives the estimating team a shared place to review quantities and the reasoning behind them. The AI drawing path remains a beta workflow: incomplete drawing sets and scans without usable text still require additional handling, and the outputs require estimator review before use.
The hardest part was not producing more numbers. It was deciding what the system could support from the drawing, what needed a person, and how to make that boundary clear in the interface. Traceability became the organizing principle for both the product and its architecture.
Captured from demo projects in the live APC Takeoff pilot. Crops focus on the workflow and exclude account details and unrelated projects. Displayed quantities are demo outputs, not independently validated estimates or business impact metrics.