ConGro AI v0.71: describe a building, get it designed — in Revit and ETABS

This is the biggest update ConGro AI has had. We went through the whole app and rebuilt the Build tab from the ground up. The first Build tab was an early version — it worked, but it was never complete. The new one designs and builds a whole building in Revit — structure, facade, interiors, mechanical, electrical, plumbing, fire protection, names and drawings — from a written description. And there is now a Build tab for ETABS too: describe a structure and get a model that is built, loaded, analyzed and designed to US codes. You see the cost before anything is built, and you can change a finished building just by typing.

1. The new Build tab for Revit

One way to build. Describe the building in as many messages as you like — typed text, pasted text, text files and pictures. Nothing is charged until you press Build this building.

The build, step by step

1. Research. Before anything is designed, the app researches the building at its real place, from the web and from the code books, against a checklist of 50–70 items that must all be ticked before the build goes on. It covers:

• site and climate: wind speed, snow, earthquake, frost depth, rain;
• zoning and site rules: height limit, setbacks, floor area ratio, parking and loading minimums;
• the code path: the IBC edition the city has adopted and its local changes, occupancy groups, construction type, height and area limits, high-rise rules;
• fire and life safety: when sprinklers, standpipes and alarms are required, exit count and width, travel distance, stair pressurization, Fire Command Center, fire pump;
• plumbing fixture counts (IBC 2902) and accessible toilets;
• accessibility (ADA / ICC A117.1 clearances, number of accessible rooms);
• energy (wall, roof and glass values for the climate zone, IECC);
• the usual mechanical system for that building type and climate, and plant room sizes;
• lifts: number and size, service lift, stretcher-size lift;
• building-type norms: room sizes, ratios, back-of-house rooms;
• structure: the usual system for that height, spans, slab depths, core size;
• special features: helipads (NFPA 418), pools, sky bridges, roof gardens;
• style and local character: facade materials usual for that city, and what your pictures show.

The research card shows each step live — plan, search, read, analyze, files, report — with the pages being read and the files being saved.

2. Requirements sheet and design intent. The full brief of the building, written before anything is built:

• the facts: stories, floor heights, areas, rooms and their sizes, code rules, the structure;
• the idea: how it looks and feels and why — massing, facade system, entrance, roof and crown, interior character per area, terraces and landscape, what each of your pictures should bring, and what NOT to do (“no flat boxy podium”).

With a design intent, every part of the building follows one idea, instead of a plain box that only meets the numbers. The sheet goes beyond the brief unless you limit it — and it never contradicts you: “keep it simple” or “only X” is followed exactly.

3. Estimate. The build stops and shows the cost at once, part by part (research and sheet already used, Exterior and Structure, Interior Layout, each trade, names and drawings), with a low and a high number and your balance. The buttons:

• Approve and build — starts only when your balance covers the high number;
• Change the plan — type plain words (“make it 22 stories and add a rooftop bar”); the app researches only the new topics, rewrites the whole sheet, lists what changed, and shows the new estimate. As many rounds as you want;
• Features — flip a switch and the estimate updates instantly;
• Cancel.

Not enough credits? The window says which switches to turn off to fit your balance.

4. Exterior and Structure (Core and Shell). Levels, grid, columns, beams, slabs, cores, stairs, lifts, shafts, the facade and the roofs, built in the model open in Revit.

5. Interior Layout (Fit-Out). Rooms with names and numbers, walls, doors, windows, ceilings, toilets, service rooms and footings.

6. Readiness check. Before the services go in, code checks that the building is ready for every trade you switched on, in seconds:

• enclosed exit stairs;
• an air room on each floor (or a plant floor with duct shafts) when Mechanical is on;
• an electrical room on each floor plus a main electrical room when Electrical is on;
• shafts beside the toilet stacks when Plumbing or Mechanical is on;
• a fire pump room and a Fire Command Center (at least 200 sf, at least 10 ft wide, 1-hour walls, IBC 403.4.6 / 911) for high-rises when Fire Protection is on.

Anything missing goes back to the design with its exact place (“Level 7: no electrical room; needs about 8 × 10 ft next to the core”) and is fixed. Anything still open is listed at the end — nothing goes missing in silence.

7. Services and fire — built by the Artery Engine (section 2). 8. Names and IDs — every element gets a full name and an ID (section 3). 9. Drawings (section 4).

Scope switches

Six switches in the Build tab Tools menu, all on by default, each with an “i” button that explains what it covers:

• Exterior and Structure (Core and Shell) — always on for a new building;
• Interior Layout (Fit-Out);
• Mechanical (HVAC);
• Electrical (Power and Lighting);
• Plumbing (Water and Drainage);
• Fire Protection (Life Safety).

Switch Interior off and the four trades grey out. The app never starts a stage or trade that is switched off. Each trade opens its own sub-options (section 2), each with its measured time, and the total time and estimate update as you switch.

Follow it all in one panel

Every step shows done / working / waiting with a live timer, what it is doing right now, credits used so far against the estimate (“1,240 of ~4,150 used”), and the pictures each step took — small thumbnails you can click to enlarge, all saved in the chat’s Books panel. The chat box locks while the estimate waits for you and while a build runs, so nothing is sent by mistake; you can always stop the build.

Come back later

Close the app mid-build and resume later — finished steps are kept. Every step of the build is saved with the building, so a lost or crashed model can be rebuilt into a blank Revit model by replaying the saved steps; the services, names and drawings then run again. Every element is referred to by its full name, not by a Revit number, so the replay is clean.

Your build files are locked

Everything a build saves on your PC — every build step, the building record, the names index, the requirements sheet, the research notes, the estimate and the logs — is encrypted. Nothing is left in plain text on disk.

Built for any shape

64 building recipes — arched hangars, stadium bowls, twisting and leaning towers, domes, shells and vaults, cable nets and membranes, stacked, cantilevered and bridging blocks, facade skins, bowls and tiers, car-park ramps, cultural and regional forms and more — each built for real in Revit, photographed and checked. Curved, barrel-vault and domed roofs, ramps and sloped floors, roof trusses, mixed structure by floor group, L-shaped, spiral and curved stairs, curved walls, beams and floor edges, doors on curved and wavy walls, and a tall hall rising beside a multi-story block are all supported.

Building-type guides

What each kind of building needs — rooms, sizes, structure, materials, codes, services and fire rules — for offices, shops, hotels, hospitals and clinics, schools, factories, warehouses, data centers, cold stores, hangars, apartments, houses and more. Each guide also drives the services and fire rules for that type.

Change a finished building by typing

• Ask a question (“how tall is the lobby?”) and get an answer from the building’s own record.
• Describe a change (“make the fins 24 in deep on L6–L17”). The app sizes it (small, medium or big), shows the cost, and waits for your choice: Approve, Use the strongest setting, or Cancel.
• It edits only the part it touches, then re-runs the services, names and drawings for the floors it touched.
• A big change (a new facade idea, a change of use, a new wing) rewrites the requirements sheet first and shows a new estimate.
• Undo takes the latest change back.
• A change days or weeks later picks up from the saved record — never a re-run of the whole build.

US units by default

Feet and inches, square feet, US door and window sizes, US code values (metric when you ask).

2. Meet the Artery Engine — Generation 1

The Artery Engine is our own services and fire engine. It lays out the building’s arteries — air, water, drainage, power and fire lines — by code rules, the same way our Rule Engine checks codes. It is not the AI guessing; it is engineering rules in code. It never stops on a clash: it lists it with its place and carries on.

What it builds, floor by floor and building-wide

• Fire protection (Life Safety): sprinkler heads on every ceiling, mains and branch pipes, risers, standpipes and hose valves in the exit stairs, the fire department inlet, the fire pump room, smoke and heat detectors, pull stations, horns and strobes with alarm wiring, exit signs and emergency lights, and fire dampers where ducts cross fire-rated walls. Fire protection by building type: system types, hazard levels and special suppression.
• Mechanical (HVAC): supply, return and exhaust ducts with their grilles; fan coil units on chilled water with condensate drains (hotel and apartment rooms get their own small unit each, fed in tight ceilings); fresh-air and exhaust risers in the service shaft; toilet exhaust up shaft risers to roof fans, with dampers, airflow regulators and one fan per riser on taller buildings; general exhaust back to the fresh-air unit or out through the rooftop units; rooftop plant sized per building type and connected to the floors; the mechanical room; kitchen hoods with grease fans; roof hatch, railings and equipment pads.
• Plumbing (Water and Drainage): toilets, sinks and fixtures facing the right way on wet walls; janitor and kitchenette sinks; cold and hot water; waste and vent pipes sized by the plumbing code with their fall; gas pipes; stacks that shift sideways at transfer floors instead of running through rooms they do not serve; roof drains and vents; the water plant room.
• Electrical (Power and Lighting): lights in every room (stairs and small rooms too), outlets, floor panels sized from each floor’s load, cable trays and wiring with circuits numbered back to their panels, electrical and generator rooms, lightning protection.
• Always included: holes cut where pipes and ducts pass through walls, floors and deep beams (curved beams too), an automatic clash fixer, a final clash check, colored 3D views and pictures per trade, and a short “done” message in the chat: what was built, where to look, and what is left.

How it routes, like a real design office

• In rooms with a ceiling, services run in the space between the ceiling and the slab above.
• Where they must run below the ceiling (a low ceiling, a beam in the way), they run along the wall edge in a bulkhead; small vertical runs inside a room go in a chase.
• In tall spaces with no ceiling — atriums, warehouses, parking, gyms, plant rooms — they run exposed, high up, neat and parallel to the grid, as is normal practice.
• Vertical runs go in shafts beside the cores and toilets; sprinkler and standpipe risers run in the exit stairs (normal US practice).
• Inside each floor the biggest and least flexible go first, as real designers do: drains (they need slope), ducts, sprinkler mains, chilled water and fan coil units, fresh air then exhaust, cable trays, devices, dampers, then wiring and panels. Each trade has its own height band in the ceiling space, and the 3D routing goes over or under anything in the way.
• Every riser stays inside the building and stops at the first roof above it.
• It measures the project’s own pipe fittings before it lays anything out, keeps every joint the room it really needs, and works on any building shape — not just the test tower.
• Identical floors are copied up the tower, so a tall building is fast.

Pick exactly what you want

Under each trade switch: the items above, one by one, each with an “i” note and a measured time. Two slow items — joining each sprinkler head to its pipe and each grille to its duct — are off by default, as on real projects where the contractor makes the final hookups. When they are on, they join devices in groups, so one bad device never blocks the rest, and any device that is slow to join is named in the report.

Generation 1, honestly: it is not perfect yet. On our 19-story stress-test tower it builds every floor’s services and fire protection and fixes most clashes itself; what it cannot fit cleanly — mostly in very tight hotel ceilings — it lists for your engineer at the end, with both elements’ full names and the exact point. Generation 2 will tighten that further.

3. Names and IDs — every element, three layers

Every element the build makes gets:

• a mark for the drawings (507, 507A, C-4, FCU-05-03, LP-5A);
• a full name in plain words (Door 507A, 3′-0″ × 7′-0″, 20-min; Column at grid C/4, Level 5; Fan coil unit 3, Level 5, serves 507);
• a ConGro ID (A-RM-L05-E-507, S-COL-L05-C4, M-FCU-L05-03).

The naming rule: full words first, the short letters only in brackets. System names, drawing titles, sheet names, view names and schedule headings spell the words out — “Fire Protection (FP) Sprinkler System - Level 5 East”, “Supply Air (SA) Duct - Level 5 East”, “Lighting Panel (LP) Level 5 A”. Short marks stay only where a tag has no room; the full name is always in the element’s own “ConGro Name” field and its Comments.

Room numbers follow facility numbering practice: the floor is the first digit(s) (Level 1 = 100s, Level 13 = 1300s, basements B1, B2), numbers rise clockwise from the main entry or stair, odd on one side of a corridor and even on the other where hotel rooms face each other, a small room inside a suite takes the suite’s number plus a letter (507A), and gaps are left so a room can be split later. Revit systems and circuits get names and numbers too. Columns off the grid are named by the nearest grid crossing and the distance.

The index keeps, for every element: name, Revit ID, floor, room, grid, type, size, system and which part of the build made it. The Chat tab and change mode use it to find exactly what you mean.

4. Drawings

• Every level’s plans in the Project Browser, in seconds: floor, ceiling, structural, mechanical, plumbing, lighting, power, trade ceiling and fire protection plans, named like “Level 5 (Office) - Mechanical (M) HVAC Plan”, each with its own view template (the other trades hidden), cropped to the building, MEP colored by system.
• Tags in one batch: rooms (name, number, area), doors, windows, walls, equipment, main duct and pipe sizes and systems, lights and devices, panels.
• Grid dimensions on floor and framing plans, level heads with heights, notes on the views (shaft walls, fire ratings), sections that really cut through the building (through the core both ways and through the service shaft), enlarged plans of shafts, plant rooms and toilet cores, and a 3D view of each floor’s services with the ceilings hidden.
• Schedules: rooms and finishes, doors, windows, equipment.
• Printable sheet set (option): sheet numbers by the US National CAD Standard (G-001 cover with the sheet list, G-002 code summary, life safety plans, A-, S-, M-, P-, EL-, EP-, FX- fire suppression and FA- fire alarm sheets), filled title blocks, north arrows, view titles; sheet names spell the words out (“Fire Suppression (FX) Plan - Level 13”).
• Every kind of drawing is made in one batch, never one by one, and after any change the drawings re-run for the floors that changed.

5. Your own objects in Revit

• Design any object by describing it. Ask for a curved reception desk, a cafe chair, a bench or a sign: it becomes a real Revit family, placed where you say — at a point, or in a room by its name or number. In our test a curved reception desk was designed and placed in about 5 minutes.
• A better version of what you have. Point at a family in your model and ask for a nicer one; every copy of it in the model is swapped. In our test 4 stacking chairs were improved and swapped in under 2 minutes.
• Doors and windows made to order. They cut their wall like Revit’s own doors and windows and sit at the right height — about a minute each.
• Bring in your own 3D files. Drag or paste them into the chat: GLB / glTF, OBJ, STL, PLY, STEP, SAT, SketchUp, Rhino, DWG and DXF become Revit families in seconds; IFC and Revit files are linked. Up to 10 files in one message, sized right (inches, feet or meters) and placed where you ask. The colors of a model’s own textures come through, and every object keeps its own colors even when you bring in many.
• Look before you bring it in. Click a 3D file in the chat and it opens in a small viewer: drag to turn it, scroll to zoom, see its size, show its mesh lines, or stand it upright if it arrived lying on its side.
• Your pictures on the building. Put a picture in a frame on a wall, or use it as a wallpaper or mural over walls and floors — always on the room side.

6. A smarter Revit Chat tab

• A smarter Agent mode for long Revit jobs. The AI thinks harder, carries its reasoning from one step to the next, and stops to think again when a step fails or a new step of its plan begins. In our test of 7 real jobs on an Autodesk sample model (a full model survey, new levels, views and sheets, tagging, a create-then-remove job and more) it used 61% fewer credits and finished jobs it used to leave half done: the full model survey went from 65 steps and unfinished to 11 steps and done.
• Same work, 40% cheaper, a third faster. Our full test of 18 everyday Chat tab jobs (14 Agent jobs and 4 questions) did the same work for 40% less and took 25 minutes instead of 37.
• Agent mode options. A small menu under Agent: work until the job is done (even a 20–30 minute job), an optional spending limit per job (200 / 500 / 1,000 or your own), let it remove what it made in that chat without asking, save after every step, and a switch for the services and fire jobs (the Artery Engine).
• Many elements in one step. “Flip every door on L2”, “turn these 12 columns 15 degrees”, “copy this row of desks 6 times”: the AI names the set once (what kind of element, which floor) and the app finds them all and does the job in one step. On our 19-story test tower, one request set the Comments of 70 doors, colored 85 columns red, tagged the 70 doors and renamed 5 floor plans, across 5 floors, in under 3 minutes — every step checked afterwards. 650 walls were changed in 7 seconds in one test.
• 12 new one-step commands for many elements: copy (also rows of copies), rotate, rename, flip doors and windows, color or halftone elements in a view, duplicate views, set view templates, add pipe and duct insulation, tag elements, place text notes, join walls and floors, and attach walls to roofs and floors (Revit 2026 and later). One bad element never stops the rest, and one Undo takes back the whole batch.
• Turning a column or beam keeps it in place. Slanted columns and beams turn their cross-section, so their ends never move; upright columns turn about their own point. The answer lists every element’s angle before and after.
• Big changes are checked first. When a change touches more than 25 elements, the app first checks every one (pinned, already removed, wrong kind) and only then makes the change.
• A command search that understands meaning. In our test of 100 everyday requests in plain words, the right Revit command is now in the top 5 for 90 of 100, up from 48 — in the Chat tab and the Build tab.
• 27 topic guides built from our live-tested Revit know-how: structure, walls and facades, doors and windows, rooms, stairs, roofs and ceilings, views, sheets and schedules, tags and text, services, fire, loads and rebar, moving / copying / rotating, families and materials, links and clash checks, exports (PDF, DWG, IFC, Navisworks), worksharing, phases and design options, drafting and revisions, and project setup. Every guide opens with “one or many”: the command for one element and the command for a whole set. The AI looks up only the sections a job needs; the right guide comes up in the top 3 for 99 of 100 requests.
• Every Revit command checked against Revit itself. All of the app’s Revit commands — every read and every change, more than 2,200 — were run one by one on a 19-story test tower. 39 commands that could stop with an error (one could even close Revit) were fixed and checked again; the rest now answer in plain words when given the wrong kind of input, so the AI knows exactly what to send instead. Two jobs that could tie Revit up for many minutes on a whole tower now say so at once and ask for one floor at a time.
• Beams now report their level. Revit keeps a beam’s level in its “Reference Level”; model reads now use it, so all 942 beams on the test model show their level and a search by level finds them.
• Fairer credits. Revit work in the Chat tab is charged by the work really done, not a fixed price per action, and a long Agent job is charged as it goes — so the same plan goes much further.

7. The new Build tab for ETABS

Describe a structure, get a designed ETABS model. The same estimate-first flow as Revit, for structural models: write what you want (or attach pictures and PDFs of the plans), and the app builds, loads, analyzes and designs it in ETABS. ETABS and Revit each keep their own steps, switches, tools and texts — they never mix.

The build, step by step

1. Research — the building code at the real site, the risk category, and the site’s own wind, snow and earthquake values. The earthquake values (Ss, S1, SDS, SD1, seismic design category, TL) come straight from the USGS for that address. Your own values always win.
2. Requirements sheet (the design basis) — stories and heights, footprint and grid, building use and risk category, loads per area use, partitions, cladding, roof and snow, the structural system per zone and per direction, materials, the codes (ASCE 7-22, IBC, AISC 360 / 341 / 358, ACI 318), drift limits, special items (transfers, cantilevers, openings).
3. Estimate — the cost at once, part by part. Nothing is built before you approve it.
4. Structure — grids, stories, columns, beams, braces, walls, cores, slabs and decks, in any shape: curved, leaning, stepped, raked, podium plus tower, transfers, cantilevers, ramps, sloped roofs. Every model is checked before ETABS sees it: every column sits on something, every beam end reaches a support, slabs are held, nothing is floating or doubled, every section is real, walls stack, every floor has its loads. Then it is sent to ETABS in one go and read back, count by count. The “Model in ETABS” row lists each ETABS step live (stories, grids, materials, sections, members, slabs, groups, loads, cases, combinations, mass) with its counts.
5. Loads and analysis — dead, superimposed dead, live by use, partitions, cladding on the edges, wind (story forces in code), earthquake (static and response spectrum, the spectrum scaled to the static base shear), the ASCE 7 combinations (with redundancy, vertical earthquake and the 100-30 rule), mass, P-delta, notional loads. The analysis runs with the ETABS window hidden (faster, no screen-refresh trouble) and ETABS comes back on screen after. Checks: stability, modal mass at least 90% both ways, base shear, drift, the torsion increase when the building twists.
6. Member design (section 8).
7. Report — tables and pictures beside the model and in the Books panel: what was built, the design settings, the loads, periods, drift per story, every member’s ratio, what changed and why, and anything left for your engineer. A short plain-words summary on top.

ETABS-only switches in the Tools menu: loads, combinations, earthquake, wind, analysis, member design, Fix failures (on by default), Optimize sizes (on / off), report. Revit switches never show in ETABS and ETABS switches never show in Revit.

Follow it in one panel. Every step live with a timer, the credits used against the estimate, and up to 10 pictures of the model per build. Every round keeps its own file: “<name>.EDB”, “<name> fix 1.EDB”, “<name> change 1.EDB” … in Documents\ConGro AI\ETABS Builds\<building> — earlier files are never overwritten. A model you already have open is never closed without your yes.

Imperial or SI. The app reads and writes the model in its own units — a kN-m model stays kN-m, a kip-ft model stays kip-ft — and its pictures and reports follow.

Pictures of the model. Plans per story, elevations, a cut along any grid line, and 3D from any angle, drawn from the model itself — with grid bubbles, story names, color by section, a legend, a scale bar, and problem members marked in red with their names.

Every member shape you use

• Steel: W, HSS (rectangular and round), pipe, HP / S / M, angles, double angles, channels, tees — by their AISC names or by size.
• Concrete: rectangle, round, T, L, box, pipe and cross members.
• Drawn shapes: steel plate shapes and concrete outlines with their bars, built in ETABS’s Section Designer.
• Tapered members, and any shape typed in by its properties.
• Floors and walls: ribbed and waffle (joist) slabs, metal deck, mats, ramps, and walls made of layers (for example a steel plate between concrete).
• Every shape checked in real ETABS.

Groups for everything. Every building gets its groups automatically: per floor (all, columns, beams, braces, walls, slabs), per type (steel / concrete columns, beams, braces, walls, slabs), per zone (tower, podium, east wing …), design groups (column stacks in two-story tiers, braces per frame line per story, beams of the same span and use), plus your own tags. So “the tower columns on L3–L5 one size up” hits exactly those members — and a request that finds nothing to change says so and stops, instead of re-running the whole building.

Change it by typing

• Ask a question (“what is the drift at L4?”) and get an answer from the report, the sheet and the analysis.
• Describe a change — “make the L3 transfer beams deeper”, “add a brace line on grid C”, “rename, add, remove or re-height stories”, “copy this story up”, “combine two stories into one”, “add an extension on the east side”, “change this floor to storage”. The app sizes the change, shows the cost (Approve / Cancel), makes it on the model as it stands (keeping the designed sizes), re-runs the analysis and the design, and writes a new file and a new report.
• A change of loads, use, code or site rewrites the requirements sheet first.
• Sizes you name yourself are held by the design — never optimized away; if one fails, the report says so.
• A request with several items gets one line per item in the done message (“done”, or “not done — why”), so nothing is skipped in silence.
• Undo puts the model back the way it was, as a new file (“<name> undo 1.EDB”).
• Faster re-design after a change: it starts from the sizes already found, stops as soon as only things no size can fix are left, and a fix round that changed nothing goes straight to the report.

Tested on real buildings, end to end in the app

• a 4-story all-steel office in Chicago: moment frames one way, chevron braces the other, composite deck floors, a curved column line, the west end a half circle;
• a 5-story all-concrete hotel in Seattle (high seismic, design category D): an elongated octagon with columns, beams, two-way slabs and special core walls;
• a mixed “mini Meridian” in Chicago: a 2-story concrete podium with a round west end and a wavy south face, a 3-story elliptical steel office tower, a concrete core full height;
• a 6-story building in Los Angeles with moment frames, changed three times after the build (stories combined, an extension added) with Undo;
• a 5-story building in Seattle with steel special moment frames, a concrete special moment frame, eccentrically braced frames and buckling-restrained braces — changed five times, including a drastic change and a groups-and-zones change, with Undo.

8. Member design in ETABS — done the way an engineer checks it

Who does what. The AI picks the system and safe starting sizes. ETABS runs the analysis, the steel design and the concrete rebar. Our own design code (no AI) builds the size lists and design groups, runs the design loop, makes every resize, sizes what ETABS does not (concrete sections, walls, slabs, drift), and writes the report. Layout problems that no size can fix (a moment beam into a column’s weak axis, a missing brace line, a needed transfer) go back to the design with their exact place.

The design loop

• Fix failures is always on by default: members that fail are resized and the design runs again.
• Optimize sizes (a switch) also makes over-strong members lighter while every member still passes, at a target ratio of 0.95 (ETABS’s own default limit).
• Steel is designed from short AISC size lists, starting at the AI’s size; a member failing at the top of its list gets a longer list. Composite floor beams get their own lists picked by stiffness, with studs and camber from ETABS’s composite design.
• After the lists, every member gets its last size fixed and the loop runs again on fixed sizes — because ETABS analyzes a member on a list slightly differently from the same size fixed. Only the fixed-size rounds count for the report.
• One round makes every change at once, in a fixed order — walls, braces, columns, drift, beams, slabs (the sideways system first, because it moves the forces).
• No ping-pong: a member that went up, down and up again is locked at the bigger size.
• It stops when a whole round changes nothing and every check passes, with a safety stop that lists what still fails.
• Faster on big models: each round re-designs only what can have moved — simple gravity beams whose size and neighbors did not change keep their result — and the final round is always a full design of every member. ETABS designed 20 members in 4 s instead of all 267 in 43 s; later rounds went from about 69 s to about 20 s. The torsion check no longer forces a second analysis every round.

Drift, sized by virtual work

When a story drifts too much, the app makes a unit-load case for that story and direction and works out each member’s share of the drift (axial, bending and shear, member by member, including the walls). The members with the most drift share per pound get stiffer in one move — braces by area, walls by thickness, moment frames by beam and column stiffness, concrete in 2 in steps. On a test with the drift limit cut in half, the old “two sizes up” rule crept from 1.18 to 1.08 of the limit in 7 rounds and still failed; the new method passed in 3 rounds. Drift is checked for earthquake (Cd × drift / Ie against ASCE 7-22 Table 12.12-1 by risk category, divided by ρ for moment frames in SDC D–F) and for the 10-year service wind (H/400 by default, H/500 or H/600 selectable, whole height and per story). The P-delta stability ratio is checked against its limit too.

Steel (AISC 360-22 / 341-22 / 358-22)

• compression, flexure with Cb from the real moment diagram, shear and combined force checks;
• the strength equations use the full steel stiffness (29,000 ksi); the 0.8 cut of the direct analysis method is used in the analysis only;
• drift checked at full stiffness where the direct analysis method’s reduced stiffness alone would make it fail (AISC 360 C2.3);
• beams under a deck are held by the deck when sagging, free between framing points when hogging; floor beams squeezed by axial load (collectors, braced-frame beams) are checked for twisting about the held flange (E4);
• X-brace halves are designed over the whole straight diagonal where no member holds the crossing;
• strong column / weak beam counts only moment-connected beams, each direction on its own, with the column’s weak axis where the beam meets it (AISC 341 E3.4a);
• moment-frame beam bracing limits (AISC 341 D1.2) reported as a warning with the brace spacing needed;
• seismic width-to-thickness limits (AISC 341 Table D1.1);
• slender HSS walls by the AISC 360-22 effective-width rule;
• reduced beam sections checked to AISC 358-22 limits;
• floor members also held to L/240 stiffness (IBC 1604.3), so a strong-but-floppy size is never picked.

Concrete (ACI 318)

• rebar first, then a bigger section: columns 1%–8% (1%–6% in special frames), our target 4% because bars double at lap splices; beams 2% target, 2.5% cap in special frames; beam shear past the Vs cap makes the beam deeper (2 in steps, width at least 0.3 h); a column stack is never bigger above than below;
• cracked stiffness for columns, walls, beams, slabs, joist floors and coupling beams;
• walls: only the walls parallel to the force count, each wall’s own concrete strength, special walls use the amplified design shear, a wall gets thicker only past the 8√f′c Acv limit; below that the report gives the horizontal bars it needs; never thinner than ACI’s minimum;
• coupling beams (ACI 318-19 18.10.7): span-to-depth, shear against 4√f′c Acw, diagonal bars sized, limit 10√f′c Acw — a table in the report;
• slabs checked panel by panel against the ACI minimum thickness for how each panel is actually held (beams both ways, one way, or flat plate) and never under the fire minimum (IBC 722.2.2.1), so one big panel never thickens a whole floor and a roof slab is never made thick by mistake;
• joist floors (ribbed and waffle) checked like the code asks: rib width, rib depth, rib spacing and top slab against ACI 318-19 9.8 / 8.8 the moment the floor is made; depth against each panel’s own span in the design, a too-shallow floor made deeper 2 in at a time; a warning when ribs run the wrong way.

Torsion (ASCE 7-22 12.8.4.3)

In seismic design categories C–F, when a story’s maximum drift is over 1.2 × the average, the accidental eccentricity is increased by the code’s Ax factor and the analysis runs again; the report shows it.

Eccentrically braced and buckling-restrained braced frames (EBF, BRBF)

The AI draws eccentric braces with a link, or buckling-restrained braces by their steel core area. Our own AISC 341-22 checks run on top of ETABS: link shear, link length, link rotation (0.08 rad shear links down to 0.02 rad flexural links), flange and web slenderness, the capacity jump for the braces and beams next to each link (1.25 Ry Vn), the BRB core (Pu against 0.9 Fysc Asc) with its core sized automatically, and the adjusted brace strengths the beams, columns and connections must carry. The report has a table for each.

Design settings done right (ASCE 7-22 Table 12.2-1)

ETABS keeps one set of design settings per model; before, every model ran on ETABS’s defaults (a special moment frame, R 8). Now they come from the building:

• the structural system per direction: steel SMF, IMF, OMF, SCBF, OCBF, EBF, BRBF; concrete special, intermediate and ordinary moment frames and walls; dual systems — with R, Cd, Ω₀ from the table, the least R where systems combine or stack, and bearing-wall systems recognized;
• each member also gets its own frame type, so a braced bay is never designed as a moment frame and gravity framing is treated as gravity framing;
• risk category and importance factor, seismic design category from SDS and SD1, ρ (1.0 or 1.3), the drift limit by risk category, direct analysis method, second-order method that follows the analysis;
• systems not allowed for the seismic design category or the height are caught and fixed at the requirements sheet, never written silently;
• your own values are used as given (with a note when they depart from the code); the AI’s choices are used only when they are on the safe side of the code;
• every setting is written into ETABS, read back to make sure, and listed in the report (“setting, value, from, why”);
• notional loads (AISC 360 C2.2b): 0.002 × each floor’s own gravity load, both directions, on every gravity-only combination.

Which frame types work where

Build tab: SMF, IMF, OMF, SCBF, OCBF, EBF, BRBF, concrete special / intermediate / ordinary moment frames and walls, and the dual systems. Code Compliance window and the Chat tab’s check and optimize tools: every ETABS frame type the model already has (they read the model’s own settings).

9. ETABS in the Chat tab

• Every ETABS command checked against ETABS itself. We ran the whole ETABS API — 1,281 commands — on a set of deliberately strange test structures (curved, sloped, transfer floors, cantilevers, cores with openings, mixed steel and concrete, braces, ramps). The AI now works from 926 commands that are proven to work. About 30 commands are broken inside ETABS itself, and around 100 belong to other countries’ design codes, so they are left out on purpose. Zero ETABS crashes in the whole run.
• 231 ready-made jobs checked and sorted (11 real bugs found and fixed), 21 new ones added, and 166 worked examples.
• Smarter command search. The AI searches for what it needs instead of carrying a huge manual. Each job it finds also says what it needs first, what usually comes next, and what to use instead. 14 ETABS topic guides.
• Code check by asking. “Check this model against the code”: steel to AISC 360-22 and 341-22 (compactness, moment-beam bracing), concrete to ACI 318-19 (columns and bars), wall shear, slab deflection, drift to ASCE 7-22 Table 12.12-1, and modal mass — failures first, then warnings, then passes. It only reads your model; it never changes it.
• Optimize by asking. “Optimize the member sizes”: walls, drift, steel W and HSS, concrete and slabs, with the UP / DOWN / weight list of every change. It always works on a copy saved beside your file (“<name> optimized 1.EDB”) — your original is never touched. It asks for your yes first.
• Set design settings by name. “Set the seismic design category to D and rho to 1.3”: shows old and new, writes it, reads it back — or a dry run that changes nothing.
• Look at the model. The AI takes its own pictures — plans, elevations, 3D from any angle, problem members marked in red — and can take a picture of the ETABS window even when it is behind other windows or minimized, without ever taking over your screen or your keyboard. ETABS comes to the front only when you ask.
• The Code Compliance window got the same fixes: no false pass, warnings shown, the check never writes your file, slabs raised to the ACI minimum before any deflection check, the full list of changes, and concrete results read on any model — not only ones made by ConGro AI.
• Safer. ETABS pop-ups are noticed and answered for you; a crashed, closed or busy ETABS is reported plainly; Stop really stops (a running command too); a command that times out never runs twice; nothing ever overwrites your file without your yes; Chat tab commands wait while a Build tab job is using ETABS.
• Faster. One long-lived connection to ETABS: a model read went from 1.3 seconds to 0.06.
• Fairer credits. ETABS chat is now charged by the real work done, like Revit, at a lower rate.

10. Credits: see the cost first, pay as you go

• The estimate comes before anything is built — in Revit and in ETABS.
• Credits are taken as the build goes, each step as it finishes, never twice.
• A change shows its cost before it is made.
• The chat box locks while the estimate waits for you and while a build runs, so nothing is sent by mistake.
• If a step stops, you get a clear message about that step and how to carry on.
• Chat tab work (Revit and ETABS) is charged by the work really done, not a fixed price per action, with clear costs under every reply.

11. The whole app

Seeing and files

• The AI sees your images directly — screenshots, photos, drawings.
• Drop files anywhere on the window, paste images; every file type is accepted and listed in the Books panel.
• PDF, Word, Excel, PowerPoint, EPUB, emails and scanned pages are read properly, page by page, keeping tables; ZIP, RAR, 7z and TAR archives are opened.

Web research

• Searches several sources at once, reads pages, follows links, and downloads PDF, Word, Excel, PowerPoint, ZIP and CAD files into the conversation’s Books panel; writes a report with numbered sources.
• The research card shows every step live.

Code books (the Rule Engine library)

• The whole library was rebuilt: lost tables restored, duplicates removed, your own paid books added, older editions kept apart.
• Much better search: exact lookups by section, table or equation number, plus meaning search.
• The AI can see the figures, charts and maps in the code books, not just the text.
• Answers cite the book and section.

Chat

• A built-in Python calculator for engineering math.
• Automatic summaries of long conversations, so they never run out of room.
• Move a build conversation over to the Chat tab when you want to keep working on it there.

Feel

• A new opening animation and an animated title-bar mark.
• Smoother everywhere: every animation was checked and reworked to stay fluid.
• The app fits any window size; side panels share the room and never squeeze the chat.
• Tidier “i” notes in every menu, with measured times for each build option.
• Settings > Diagnostics sends a full support bundle with one click.

Always up to date

• The app’s know-how updates itself in the background, so improvements reach you without a new install.

12. New installer and first launch

• A new installer look in the ConGro AI style, with clear steps (“Step 1 of 3: Preparing”, “Step 2 of 3: Copying the app”, “Step 3 of 3: Finishing up”).
• A leaner install. The analysis engine now ships as one packed file instead of many thousands of small ones, and about ten thousand files the app never uses were left out — so copying is quicker and the bar keeps moving.
• First launch: the opening screen shows the engine being set up — first run only — with a live percentage. Later launches open straight away.

Coming next

• Artery Engine Generation 2 — tighter routing in tight ceilings and fewer clashes left for the engineer.