# ExtractControlPolygon

## <img src="/files/BTa2QICz1UL9OWdG2JCl" alt="" data-size="line"> ExtractControlPolygon <a href="#profiles" id="profiles"></a>

The ExtractControlPolygon command fits a polyline through the control points of a curve or a polygon mesh through the control points of a surface.

### **Steps**

1. Select curves or surfaces.\
   This creates polylines and/or meshes that have vertices at the original objects' control points.

### Supported input

* Curves, Polycurves, Surfaces
* SubDs

### Command-line option

* OutputLayer:&#x20;

  Specifies the layer for the results of the command.

  1. **Current**: Places the results on the current layer.
  2. **Input:** Places the results on the same layer as the input curve.

     *Note: If the input object is in a model that is attached using Worksession, the object will be                 placed on the current layer.*
  3. **TargetObject:** Places the results on the same layer as the target surface.
* SubCrv:&#x20;

  Type subcrv to select part of a curve as input.

For more information, please refer to the [Rhino documentation](https://docs.mcneel.com/rhino/8/help/en-us/commands/extractcontrolpolygon.htm#\(null\)).


---

# Agent Instructions: 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:

```
GET https://docs.rhinoartisan.com/commands/subd/creation/extractcontrolpolygon.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
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.