# HiddenLineDrawingParameters class

Namespace: [Rhino.Geometry](https://developer.rhino3d.com/api/rhinocommon/namespace/rhino.geometry.md) · Assembly: [RhinoCommon](https://developer.rhino3d.com/api/rhinocommon/assembly/rhinocommon.md)

```cs
public class HiddenLineDrawingParameters
```

Input used for computing a hidden line drawing

## Constructors

- [HiddenLineDrawingParameters](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/ctor.md): default constructor

## Properties

- [AbsoluteTolerance](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/absolutetolerance.md): Absolute tolerance is used to decide if curves overlap or intersect. A suggested value is to use RhinoDoc.AbsoluteTolerance
- [Flatten](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/flatten.md): Flatten the computed geometry
- [IncludeHiddenCurves](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/includehiddencurves.md): Include hidden curves in hidden line drawing (default is true)
- [IncludeTangentEdges](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/includetangentedges.md): Include tangent edges in hidden line drawing (default is true)
- [IncludeTangentSeams](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/includetangentseams.md): Include tangent seams in hidden line drawing (default is true)
- [OccludingSectionOption](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/occludingsectionoption.md): Enable occluding section option (default is false)

## Methods

- [AddClippingPlane](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/addclippingplane.md): Specify clipping planes that are active for this view.
- [AddGeometry](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/addgeometry.md): (4 overloads) Add geometry that should be included in the calculation
- [AddGeometryAndPlanes](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/addgeometryandplanes.md): (4 overloads) Add geometry and its active clipping planes to be included in the calculation
- [SetViewport](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.hiddenlinedrawingparameters/setviewport.md): (2 overloads) Set the viewport for the hidden line drawing (HLD). The viewport supplies the projection that determines the visibility of curves, and the HLD coordinate system in which the resulting curves are represented. The HLD-coordinate system is a right handed system for 3-D model space, in which the 3rd coordinate direction is the projection direction. In particular the z-coordinate direction points from the scene toward the camera.