What is Instant Design Check in PDFDepth?

The check that almost never happens

Everyone in AEC has done the mental math: "that beam looks light for the span." Verifying it properly means pulling the dimension off the sheet, estimating the tributary width, choosing loads, opening analysis software, building a model, running it, and comparing the result against the member on the plan. On a deadline, that twenty-minute detour happens for one beam in fifty — the rest ride on intuition.

The cost shows up downstream: a plan reviewer who can't spot-check a member, an estimator pricing an undersized header, a PM fielding an RFI that a thirty-second check would have prevented. The information was always on the sheet — the friction was in getting from pixels to numbers.

Box, review, check — three steps

• Toggle Instant Design Check in the right panel and drag a box around the member — a beam on a framing plan, a header in a section, a column in an elevation.
• The reading pass identifies members in the region: spans between supports, support types, the printed designation (W12x26, 12x24 CONC BM), tributary width, and any loads written on the drawing. Every finding comes with a confidence level and evidence — which labels and dimensions it used.
• The review panel shows the proposed model with every field editable. Fix a span, change a support from fixed to pinned, override the loads — nothing is analyzed until you confirm.
• Run Checks solves the model deterministically and reports demand versus capacity per member. Apply Markups stamps the result onto the drawing as ordinary annotations — a colored boundary and a callout like "B1: W12x26 ✓ Mu=89.2/φMn=139.5 k·ft, δ=L/410".

The AI reads the drawing — it does not do the math

This is the part worth understanding, because it is what makes the feature trustworthy. The AI's only job is reading: turning the contents of your rectangle into a proposed model you can inspect and correct. Every number it produces is a suggestion with evidence attached — never a hidden input to a black box.

Once you confirm the model, the math is fully deterministic. The same beam finite-element formulation used in commercial analysis software — the direct stiffness method — computes reactions, shear and moment diagrams, and service deflection under the ASCE 7 load combinations (1.4D, 1.2D + 1.6L, 1.2D + 1.0Lr). Design checks then run to the actual code provisions: AISC 360 flexure, lateral-torsional buckling, shear and column buckling for steel; ACI 318-19 required reinforcement and shear capacity for concrete. Same model in, same answer out — every time, and auditable.

If a member fails, the check doesn't just flag it — it proposes the fix. A steel beam gets the lightest W-shape that passes; a concrete beam gets a required steel area and a suggested rebar arrangement that fits the section.

What it checks today

Unbraced length defaults to the governing span and Cb to 1.0 — the conservative side — and both are editable. Concrete checks assume f'c = 4,000 psi and Grade 60 rebar; those defaults are visible in the panel rather than buried.

Where it earns its keep

• Engineers of record doing back-checks: verify the beams a reviewer is most likely to flag before the set goes out the door.
• Plan reviewers and building departments: spot-check member adequacy during review without opening a second application — the check rides along as a markup in the file.
• GC estimators and PMs: sanity-check a suspicious header or beam during bid review, and price risk with numbers instead of gut feel.
• RFI and field triage: when a framing question comes in from the site, box the member and get defensible reactions and demand in under a minute.
• Specialty engineers: quick screening on lanai headers, lintels, and miscellaneous framing where a full model is overkill but intuition isn't enough.

Honest limits

This is a screening and verification tool, not a sealed calculation package. The AI can misread a messy detail — that is exactly why the review step exists and why every proposed value carries confidence and evidence. Wood member checks and concrete column design (P–M interaction) are not in this release; those members get the full demand analysis but no capacity check. And wind, seismic, connection, and serviceability criteria beyond L/240 are outside the checks' scope.

The right mental model is a very fast, very honest first pass: it tells you which members deserve a closer look, with numbers you can trace — before the question becomes a change order.