> For the complete documentation index, see [llms.txt](https://docs.openbrim.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.openbrim.org/templates/cadd/dimensiondiameter-cadd.md).

# Diameter Dimension

A **Diameter Dimension** labels the diameter of a circular feature — piles, drilled shafts, anchor bolts, dowels, casings, circular openings, round columns. Use diameter for closed circular features; use Radius Dimension for arcs and curved edges.

Pick the circle, and the dimension shows the diameter with a leader.

## Text and units

**Label:** Override text. Leave blank to use the auto-computed diameter.

**Prefix:** Text before the value. Default `⌀` (the conventional diameter symbol).

**Suffix:** Text after the value.

**Precision:** Number of decimal places.

**Unit Style / Length Unit:** Units for the diameter value.

## Placement

**Center X / Center Y:** Override the leader's pivot point. Default uses the dimensioned circle's center.

## Typography

**Text Height:** Text size in real units.

**Font Family / Font Weight / Font Style:** Font controls.

## Notes

For piles and drilled shafts, the standard convention is `⌀ <size>` (e.g., `⌀ 24"`). For anchor bolts and dowels, the standard is also diameter, often combined with a length and quantity in a separate note (e.g., `(4) ⌀ 1" × 18" anchor bolts`).

When dimensioning many identical circles (a pile group, a bolt pattern), call out one and add a note describing the rest, rather than placing one diameter dimension per circle.


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://docs.openbrim.org/templates/cadd/dimensiondiameter-cadd.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.