> 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/dimensionradius-cadd.md).

# Radius Dimension

A **Radius Dimension** labels the radius of a circular arc — fillet returns, parapet ends, drilled-shaft outlines, curved deck edges, anything where a radius callout is the right way to communicate the curvature.

Pick the arc or circle, and the dimension shows its radius with a leader from the curve to a label.

## Text and units

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

**Prefix:** Text before the value. Default `R` (the conventional radius callout prefix).

**Suffix:** Text after the value (e.g., a unit symbol).

**Precision:** Number of decimal places.

**Unit Style / Length Unit:** Units for the radius value. Same options as Linear Dimension.

## Typography

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

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

## Notes

Use a Radius Dimension when the curvature itself is the key feature being communicated — fillet returns, parapet end radii, transition curve radii. For circular openings (piles, drilled shafts) where the diameter is the more natural callout, use a Diameter Dimension instead.

The radius arrow conventionally points from the label to the arc. Drag the leader handle to position the label.


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