Dimensioning, Annotation & Schedules
The language that makes a drawing buildable — and coordinated.
The language that makes a drawing buildable. Learn the two dimensioning systems — chain (which accumulates tolerance) versus baseline (which measures every dimension from one datum) — the overall-then-sub rule, and the crucial interior distinction between dimensioning to structure and to finish. Then annotation with leaders, level markers, section marks and tags; the line-weight hierarchy as information, not decoration; and the schedules where the tag is the hinge and the schedule is the single source of truth.
Learning objectives
By the end of this lesson, you will be able to — mapped to the course outcomes for Interior Graphics II:
Dimension with chain and baseline systems and the overall-then-sub rule.
Distinguish dimensioning to structure from dimensioning to finish and declare it.
Annotate with leaders, level markers, section marks, tags and the north point.
Read line-weight hierarchy as information, and coordinate a drawing with schedules.
Dimensioning systems
Chain versus baseline dimensioning and the overall-then-sub rule, and dimensioning to structure versus to finish with grids, datums and level markers.[1, 4]
Chain vs baseline
Two governing systems (IS 11669 / SP 46). CHAIN (running) dimensioning places dimensions end-to-end, each measured from the previous point — fast and compact, but TOLERANCES ACCUMULATE along the chain, so use it for a run of equal openings. PARALLEL (baseline) dimensioning measures every dimension from ONE common origin (datum), stacked parallel — it eliminates cumulative error and is used where accuracy matters (setting-out grids, tile/stone). The OVERALL-THEN-SUB rule: the outermost string carries the overall dimension, inner strings the sub-dimensions, and the sub-dimensions must SUM to the overall — a built-in self-check.[1]
Line weight, annotation & schedules
The line-weight hierarchy carried to professional standard, annotation with leaders, tags and the north point, and the schedules that coordinate via the tag.[1, 2, 3]
Leaders, tags, north
ANNOTATION rules (IS 9609 / IS 962). LEADERS run thin from a note to the feature, ending in an arrowhead on an edge or a dot inside an area — one note, one target, no crossing. NOTES are concise and imperative — general notes on the cover, specific notes local. Dimension figures sit ABOVE and ALONG the line and read from only TWO directions (bottom and right), never upside-down. Arrowheads are filled (length ≈ 3× width), or architectural OBLIQUE ticks — be consistent. Every SYMBOL used appears in a legend; the NORTH POINT is on all plans; a SECTION MARK (cutting line + arrows + tag 'A / A-401') keys to the section sheet; and each opening carries a TAG (D1, D2…, W1, W2…) that keys to the schedule.[2]
At a glance
| Aspect | One side | The other |
|---|---|---|
| Long run of dimensions | Chain: fast, but tolerance accumulates | Baseline: from one datum — no cumulative error |
| Which face to dimension | Myth: whichever is convenient | Reality: to structure OR to finish, consistently, declared |
| Line weight | Myth: aesthetic neatness | Reality: information — cut vs seen vs surface |
| How much to dimension | Myth: put every dimension everywhere | Reality: say it once, sub-dimensions sum to overall |
| Repeated doors | Myth: re-letter each one | Reality: tag D2, describe D2 once in the schedule |
Key terms
Chain runs end-to-end (tolerance accumulates); baseline measures all from one datum (no cumulative error).
To the bare shell (set out before finishes) versus to the finished face (what joinery must fit) — declare which.
A filled/half-filled triangle with a value (e.g. +2.700) that dimensions a height from the FFL datum.
Thickest = the cut, medium = seen, thin = surface/dimensions, thinnest = grid/hidden — weight is information.
A code (D1, W2…) on the drawing that keys to a schedule row — the drawing carries the tag, the schedule the detail.
A coordinating table (door, window, finishes, ironmongery) that is the single source of truth for repetitive items.
Drawing task
Take a simple room plan and dimension it two ways: once with chain (running) dimensioning and once with baseline dimensioning from a single datum — and note which you would use for setting out a tiled floor and why. Add an overall string with sub-dimensions that sum to it, mark the finished floor level with a level marker, and state whether your dimensions are to structure or to finish. Then compile a three-row door schedule (D1–D3) with size, type, material, finish and ironmongery set, and tag those doors on the plan.
Self-assessment
1. To eliminate cumulative tolerance error along a setting-out run, you use —
2. On a working drawing, the thickest/darkest line should be —
3. In a schedule system, a door drawn on the plan as 'D2' carries —
Recap
References & further reading
- [1]BIS: IS 11669:1986 (general principles of dimensioning); IS 9609:2001 (lettering); IS 962:1989 (annotation, symbols, north point).
- [2]Francis D.K. Ching, Architectural Graphics (dimensioning, line hierarchy, notation, symbols).
- [3]David Kent Ballast, Interior Detailing: Concept to Construction (schedules, tagging, dimensioning to finish vs structure).
- [4]SP 46:2003, Engineering Drawing Practice for Schools and Colleges, BIS (line types, dimensioning, lettering compiled).
Further reading
- Francis D.K. Ching — Architectural Graphics.
- David Kent Ballast — Interior Detailing: Concept to Construction.
- BIS IS 11669 & IS 9609 (dimensioning & lettering).
Sources gathered and fact-checked June 2026. Published values vary by source, sample and method — treat as indicative and confirm against the cited standard before structural use.
The author
Amogh N P
Architect, interior designer, and creative polymath. Studio Matrx began in his notebooks — his vision of design made honest, useful, and open to everyone. Its Academy is written and taught in his memory, and free, forever.
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