Annotation and dimensioning discipline

Annotation is where a model becomes a document, and where the discipline of "never type it twice" gets tested.

Model vs. annotation

Change a view from 1:100 to 1:50 and annotation text stays the same printed size while the model gets bigger. That's the entire point, and it's why authoring a symbol from a model template is a redo — the text will scale with the building.

Detail components are a third thing: 2D model-space families that live in one view but scale with the model. Used for standard details.

Tags, not text

A tag reads a parameter off the element it points to. Edit the model, the tag follows.

• TG — Tag by Category. The Options bar controls leader on/off, orientation (horizontal/vertical), and leader style.
• Tag All Not Tagged (Annotate → Tag All) — tags every untagged element of chosen categories in the view at once. Enormous time-saver, and the way to guarantee nothing is missed.
• A tag shows ? when the parameter it wants is empty. That's Revit telling you the model has a data gap — go fill it in, don't replace the tag with text.
• Tags are category-specific: a Door Tag reads Doors. If no tag family is loaded for a category, Revit says so and offers to load one.
• Multi-Category tags exist, and they can only read shared parameters — which is another reason shared parameters matter.

Authoring a tag

File → New → Annotation Symbol (or a category-specific tag template). Then place a Label, not text. A label is bound to a parameter:

• The label dialog lets you combine multiple parameters with prefixes, suffixes, and line breaks — [Type Mark] on one line, [Width] × [Height] on the next.
• Sample values let you see what it'll look like without a project.
• To label a shared parameter, add it to the tag family from your shared parameter file. This is the mechanism that lets you tag custom data.

Keynotes

A keynote is a tag driven by an external text file, so numbered notes are identical across the whole set.

09		Finishes
09 29 00	09	Gypsum Board
09 29 00.A1	09 29 00	5/8" gypsum board on metal studs

Set the file in Annotate → Keynote → Keynoting Settings. Then keynote by element, by material, or as a user note. A Keynote Legend schedule collects the ones used in a view or sheet.

If your firm has a keynote file, use it — it's the difference between a coordinated set and 400 slightly different versions of the same note.

Dimensioning

The part of a set that gets scrutinized hardest.

What to dimension to

Dimension to what gets built from it:

• Grid lines — contractors set out from grids.
• Structural faces — the face of concrete, the face of stud.
• Critical clear dimensions — accessible clearances, corridor widths, door clearances. These are code compliance and must be explicit.

Not: whatever wall face happened to be under your cursor when you clicked.

Layer your strings

Three tiers, outermost first:

├─────────────── overall building ───────────────┤   ← tier 1
├──── grid 1-2 ────┼──── grid 2-3 ────┼── 3-4 ──┤   ← tier 2
├─ 3'-6" ─┼── 12'-0" ──┼─ 2'-8" ─┼─ ... ─┤          ← tier 3

Anything a builder needs should be derivable without adding numbers up across tiers.

The tools

• DI — Aligned dimension. Pick references, then click to place the string.
• Options bar before you dimension: choose what walls get picked — Wall Centerlines, Wall Faces, Center of Core, Faces of Core. Changing your mind afterwards means redrawing.
• Pick: Entire Walls with the Options sub-dialog auto-dimensions openings, intersecting walls, or centrelines along a whole wall in one click. Very fast for a first pass.
• Witness lines — the individual references in a string. Select the dimension and drag the small grips to add or move references, or Edit Witness Lines to add/remove by clicking. This is the skill that makes dimensioning fast; most people redraw instead.
• Linear, Angular, Radial, Diameter, Arc Length — the other dimension types, all on the Annotate tab.
• Baseline and Ordinate dimension styles exist as dimension types, if your standard uses them.

You cannot lie about the model

Revit will not let you type over a dimension value. This is deliberate — the number comes from the geometry.

What you can do:

• Add a prefix, suffix, above, or below text (select the dimension, click the value, and the Dimension Text dialog offers these).
• Replace with text — allowed, but it must not look like a number. Revit blocks numeric replacements specifically.

If a dimension reads wrong, the model is wrong. Fix the model.

Locking dimensions

Click the padlock on a dimension and it constrains the model — moving one element moves the other. Genuinely useful for maintaining a critical clearance.

It is also over-constraining, and the cause of "Constraints are not satisfied" errors weeks later. Use it deliberately and sparingly. RC reveals every constraint in the view.

Dimension types

Like everything, dimensions have types controlling tick mark, line weight, text size, witness line extension, and units. A set should use two or three, defined in the template. Don't create a new type to fix one string.

Text notes

Legitimate uses: construction instructions, general notes, references to specifications.

Illegitimate use: any value that exists as data in the model. If you're typing 3'-0", Office 101, or 2 HR, stop and use a tag.

Practical:

• TX places text. Leaders are added from the ribbon after placement (or before, via the leader buttons).
• Text is a type — size, font, and background are type properties. Two or three types per project, from the template.
• Background: Opaque masks what's behind the text. Useful over hatching, and a source of confusion when it hides something you needed.
• Spell check is F7, and it works on the whole view or the selection.

Symbols, detail lines, and filled regions

• Symbols (Annotate → Symbol) — annotation families placed for things like north arrows, section marks, and graphic scales.
• Detail lines (DL) — 2D lines in one view. Line style is chosen from the Line Style dropdown. Legitimate for detail drafting; illegitimate for "drawing" something that should be modelled, and definitely illegitimate for faking revision clouds.
• Filled regions — a sketched area with a fill pattern and boundary line style. For poché in details. Masking regions are the same but opaque, for hiding model geometry in a view — use sparingly and never to hide a modelling problem.

Revision clouds

Annotate → Revision Cloud, then set the cloud's Revision property to a revision defined in View → Revisions.

The payoff is automatic: the title block's revision schedule populates itself on every sheet containing a cloud from that revision. Mark the revision Issued and it locks against further editing.

Drawing a cloud with detail lines produces a drawing set that lies about its own history. It's one of the few things in Revit that's straightforwardly wrong to do.