Appearance
Glossary
Fablnx borrows most of its vocabulary from detailing, but a few words mean something specific here. This page defines every term the rest of the guide uses. If a page confuses you, the word you're missing is probably below.
The drawing set
Contract drawing set
The PDF a structural engineer issues — the drawings you're detailing from. One project holds exactly one set.
Sheet (page)
One page of the set. Fablnx uses sheet and page interchangeably; the Files panel lists them all.
Classification
What the copilot decided a sheet is — general notes, steel structure, and so on. It sorts the Files panel into groups. You can override it at any time; see Files & the page viewer.
General notes
The written specification sheets in the set — grades, bolt and weld defaults, standards. The copilot reads these into the design spec.
Design spec
The structured, AISC-shaped summary of the general notes that the Lectora Lectora extracts. It's the fallback for any value a drawing doesn't state — most importantly, a member's grade.
Vector geometry vs. the scanned image
Every sheet can be read two ways: as the image of the page, or as the vector geometry Fablnx pulls out of the PDF. Detection and region-drawing work on the geometry.
Region
An outline you draw around one drawing on a sheet — a single framing plan on a sheet that holds three. A region is what a scene is built over.
Building the model
Scene
One view you are tracing: a plan or an elevation, usually over one region. A scene is drawing-shaped — it holds everything that sheet says, in the sheet's own terms. It is not the model; it becomes part of the model when you commit it.
Plan
A scene that cuts horizontally through the building at one level. It looks down and reports what it sees at that cut.
Elevation
A scene that stands vertically, running along one or more grid lines. It draws the whole member from a stated bottom to a stated top — which is how a column gets a height.
Underlay
The drawing showing through beneath the scene canvas, so you trace on top of it. Its opacity is adjustable.
Grid line
One of the building's axes — the lines a plan bubbles A, B, 1, 2. Every member is anchored to grid lines, which is what lets the same column be recognised on two different sheets.
Named line vs. offset line
A named grid line is one the drawings labelled, and it gets a bubble.
An offset line is one the drawings show but never named — a face, an opening edge. Fablnx names it from its position, like CO-10+14'-11", and draws it dashed with a flat tag. It locates something without being one of the building's own axes, so no elevation is ever taken along one.
An offset line is never pushed into Tekla. It is Fablnx's own working — a place for steel standing off the grid to be measured from — and a detailer opening the model should see their grid, not our arithmetic. Members that stand on one still land in exactly the right place; the model simply has no grid line there. Radial spokes are not offsets, despite the similar name, and are pushed like any other line the drawings show.
Family (direction)
All the grid lines running the same way. A plan usually has two families crossing each other, and may have more where a canted sub-grid runs across the main one; an elevation runs along one family and crosses the other.
Two families are enough to fix the model in space. Any family beyond the second is placed where the sheet draws it crossing the first two — so if a drawing shows a canted grid but never shows it meeting the main grid, its lines are listed as unplaced rather than put somewhere invented.
Intersection
Where two grid lines genuinely cross. On a plan, this is where steel can stand.
Dimension
A recorded distance between two grid lines, read off the drawing's own dimension string. Dimensions are what actually locate the grid — not where lines sit on the paper, which is not reliably to scale.
Measured dimension
The exception to that. Where a sheet dimensions nothing at all between two groups of grid lines, there is no printed number to prefer, so Calibrate measures that one gap off the drawing and records it — shown as Measured off the sheet. It is the only dimension whose length comes from the paper, it is never written across a gap the drawing already dimensions, and it disappears by itself once a printed dimension covers the same span. Treat it as a value to check: type the real length over it and it becomes an ordinary hand-set dimension.
Calibrate
Reading the drawing's dimension ticks and bay distances so that distances mean feet. Until a scene is calibrated, it has no scale and several tools stay locked.
Level
A storey of the building, with a name and a true elevation — L2, 73'-1". Levels are shared by the whole project, so they are edited in one place: the Structure panel. A plan cuts one level.
Cut level
The level a plan cuts through — the same setting the New scene dialog calls Level. In the scene editor it is labelled Cut, in the scene toolbar (Select tool, nothing selected). If something tells you to give this scene a level first, that's the control it means.
Level line
On an elevation, a horizontal you have drawn and pinned to a project level. Steel standing on it takes that level's height.
Offset elevation
On an elevation, a horizontal at a height this sheet states and no project level names — a base plate at 13'-5½", a mezzanine, the underside of a rafter. It is named from the nearest level below it, so it reads L2+3'-6", exactly the way an offset grid line is named off CO-10.
An offset elevation is not a floor and never becomes one. The same callout can appear three times on one sheet at three different heights, so promoting them to project levels would fill the schedule with storeys the building doesn't have.
Slant line
A sloped datum — a level line that isn't horizontal. A rafter. Drawn between two intersections, in a warm colour so it reads as neither a level nor a grid line. Once one exists, every vertical it crosses becomes a place you can build on.
Station
The place where steel stands: a grid intersection — normally two crossing grid lines — at one level. It's the unit the model uses to say where: a column stands at one station, a beam or a brace runs between two. Two plans naming the same intersection at two levels are two stations, which is why a section change between them is a splice and not a conflict.
You rarely type the word, but it explains the wording of some findings: "a station takes one column."
Work point
A member's end point — where its axis is set out. Lengths and clearances are measured between work points, not between steel faces. A slant line is drawn between two of them.
Cut offset (setback)
How far short of its work point a beam's steel actually stops — the clearance a fitter needs to swing the piece into place. 1/2" unless your design spec says otherwise. The work point does not move: the beam's line still runs to the grid, and the steel stops short of it at both ends.
Member
Any piece of steel you place: a column, a beam or a brace.
Profile (section)
The shape size — W14X90, HSS6X6X1/2. Autocompleted from the full AISC shapes catalog.
Grade
The steel grade — A992, A500-GR.B. Can be left blank: it's filled from the general notes for that shape family when the sheet is pushed.
Mark
The label the drawings put on a member — C1, B12. It is the piece mark the member carries in the takeoff, and the key the project's schedule turns into a profile.
Schedule
The project's mark → profile table: a column schedule and a beam schedule, edited in Structure → Schedules. Detection reads it as the vocabulary of marks it can name members from — alongside the full AISC catalog, so a section written out in full is matched with or without a row here — and a mark entered once names every member tagged with it, on every sheet. The same mark can only appear once per schedule, though a column and a beam may share one. Not to be confused with the level schedule — the project's list of levels.
Callout
Text on the drawing that names something — a grid bubble, TOS EL 42'-0", W14X26. Many steps in Fablnx finish by clicking the drawing's own text rather than typing.
Splice
Where a column changes section. Two plans naming different sections for the same intersection at different levels describe a splice — correct, and not a conflict.
The AI
The copilot
The panel on the right, and what runs behind it: the Assistant you talk to, and the stages that read a set when it lands.
Assistant
The one you type to. It decides what to do, reads what it needs, and asks you before it changes anything.
Stage
One fixed pass over a set, run for you when the file lands: Triage (identify the steel sheets), the callout sweep (link each callout to the detail it names) and Lectora (read the general notes). A stage does one job and decides nothing — which is what makes it different from the Assistant.
Triage and Lectora each have a card in the copilot panel. The callout sweep does not: it has nothing to say while it runs, so what it finds arrives as an RFI.
Detection
The AI first pass over a scene — finding the grid, the columns, the beams, and matching sections to them. Every detect step is run by you, manually, from inside a scene. Nothing detects on its own.
Fill from the model
Filling a scene in from what the building already knows, rather than from the sheet — carrying columns up from the level below with their profile, grade and orientation, and beams and braces across from the same level. It's how a sheet gets facts it never states.
The building is your Tekla model, and only that: steel standing in Tekla, matched to your sheet by the grid lines it stands on and the level it sits at. Your other drawings are readings of drawings, not the building, so they no longer teach — which is what makes a section you corrected by hand in Tekla the one the next sheet inherits.
Review detections
An auto-play tour that flies the canvas to each detected item in turn so you can check the copilot's work and delete what doesn't belong.
Coordinating
Validate
The check that runs before a scene can join the model. It asks two questions in order: is this sheet complete on its own? and then does it agree with everything the building already knows?
RFI
Request for Information — one finding from validation. Every RFI names what's wrong and where, and clicking it jumps you to the spot on the drawing. Most also carry a one-line Fix: hint; six rules show only their message. RFIs cannot be dismissed: one answers itself when the underlying problem is gone, and reopens by itself if it returns.
Push
Writing the building into the open Tekla model. The server re-checks the sheet, fills any missing grades from the general notes, and refuses outright if anything is still open. Pushing the same sheet again changes nothing — the write is a reconciliation, not an append.
There is no withdraw: nothing joins the building, so nothing leaves it. Delete a scene and its steel goes out of the model on the next push.
The world
The Tekla model — the building as it actually stands, including anything you have drawn or corrected there yourself. Fablnx reads it and writes into it. It keeps no building of its own, which is why everything that touches the building needs Tekla open: there is nothing else to answer from.
Unplaced
Something a sheet draws but can't be put anywhere yet — an undimensioned grid line, a member with no locatable anchor. Named with the reason after a push, so it reads as a to-do list rather than a silent gap.
Clash
Two pieces of steel wanting the same space. A member's body is the box its section sweeps along its work line, so how much room it takes depends on which way you approach it: a W24X55 is 24 inches deep standing up and 7 inches wide across its flange, and two of them side by side on a plan are separated by the 7. A member that ends inside another is framing into it — a beam landing on a column — which is a connection and not a clash. The overlap is reported in the message for a detailer to judge. Clashes surface as validation findings — the 3D view has no clash display.
A column keeps a circle in plan rather than a box: a plan does not state which way its flanges face, so it is sized by the circle that contains it.
Takeoff (ABM)
The advance bill of material — every member rolled up by mark, with quantity, profile, grade, length and weight, exportable to CSV.
Where to go next
- Never used Fablnx? Start with What is Fablnx?.
- Want to build something end to end? Your first model.
- Stuck on a greyed-out button? Troubleshooting.