> For the complete documentation index, see [llms.txt](https://wiki.mksdtech.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.mksdtech.com/beam/beam-for-rhinoceros/linework.md).

# Curves & Linework

How Rhino® curves arrive in Autodesk® Revit™

BEAM exports Rhino curves together with solids and meshes. In Revit they become model curves.

Supported curves: lines, polylines, arcs, circles, ellipses, NURBS curves and polycurves.

## Curves in a family

Curves assigned to a family are placed inside that Revit family as model curves.

The curve's **Subcategory** becomes its line style. To use a style from the Revit family template, type its name, for example `<Hidden Lines>`. If the subcategory does not exist, Revit creates it.

## Curves with no family

Curves without a family are exported too. In Revit, **Import Loose Curves** creates them as model curves directly in the project, with a line style named after their subcategory.

Solids and meshes with no family go into a family called `no_name`. Assign a family in Rhino to control how they arrive.

## Curve options in Revit

The [BEAM](/beam/beam-for-revit/beam.md) and [BLOCS](/beam/beam-for-revit/blocs.md) import dialogs have a **Curve Options** section.

| Option                  | Default | What it does                                                                            |
| ----------------------- | ------- | --------------------------------------------------------------------------------------- |
| **Import Curves**       | On      | Import lines, arcs, circles, ellipses and polylines.                                    |
| **Import Nurbs**        | Off     | Import the lines and arcs Rhino produced from NURBS curves. Needs **Import Curves**.    |
| **Import Loose Curves** | Off     | Create curves with no family in the project. Needs **Import Curves**. BEAM dialog only. |

{% hint style="info" %}
Revit has no free-form model curve. BEAM converts each NURBS curve into lines and arcs on export. Complex curves can produce many segments, so **Import Nurbs** is off by default.
{% endhint %}

{% hint style="warning" %}
If a *.beam* holds more than 2,000 curve segments, Revit asks before importing them. That many model curves can slow Revit down.
{% endhint %}