# Triangle3d struct

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
[StructLayout(LayoutKind.Sequential, Pack = 1, Size = 72)]
public struct Triangle3d
```

Represents a triangle, modeled using double three points that use double-precision floating point numbers.

## Constructors

- [Triangle3d](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/ctor.md): Instantiates a new triangle.

## Properties

- [A](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/a.md): Gets the first triangle corner.
- [AB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/ab.md): Gets the triangle edge connecting the A and B corners.
- [AltitudeA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/altitudea.md): Gets the altitude line starting at corner A.
- [AltitudeB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/altitudeb.md): Gets the altitude line starting at corner B.
- [AltitudeC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/altitudec.md): Gets the altitude line starting at corner C.
- [AngleA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/anglea.md): Gets the angle at the A corner.
- [AngleB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/angleb.md): Gets the angle at the B corner.
- [AngleC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/anglec.md): Gets the angle at the C corner.
- [Area](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/area.md): Gets the area inside this triangle.
- [AreaCenter](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/areacenter.md): Gets the triangle area centroid.
- [B](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/b.md): Gets the second triangle corner.
- [BC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/bc.md): Gets the triangle edge connecting the B and C corners.
- [BoundingBox](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/boundingbox.md): Gets the bounding box of this triangle.
- [C](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/c.md): Gets the third triangle corner.
- [CA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/ca.md): Gets the triangle edge connecting the C and A corners.
- [Circumcenter](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/circumcenter.md): Gets the triangle circumcenter.
- [Circumcircle](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/circumcircle.md): Gets the circumcircle of this triangle.
- [MedianA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/mediana.md): Gets the median line starting at corner A.
- [MedianB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/medianb.md): Gets the median line starting at corner B.
- [MedianC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/medianc.md): Gets the median line starting at corner C.
- [Orthocenter](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/orthocenter.md): Gets the triangle orthocenter.
- [Perimeter](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/perimeter.md): Gets the perimeter of this triangle. This is the sum of the lengths of all edges.
- [PerpendicularAB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/perpendicularab.md): Gets the perpendicular bisector for edge AB.
- [PerpendicularBC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/perpendicularbc.md): Gets the perpendicular bisector for edge BC.
- [PerpendicularCA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/perpendicularca.md): Gets the perpendicular bisector for edge CA.

## Methods

- [BarycentricCoordsAt](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/barycentriccoordsat.md): Gets the projection of a point onto the barycentric coordinates.
- [ClosestParameterOnBoundary](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/closestparameteronboundary.md): Gets the parameter on the triangle boundary closest to a test point.
- [ClosestPointOnBoundary](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/closestpointonboundary.md): Gets the point on the triangle boundary closest to a test point.
- [PointAlongBoundary](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/pointalongboundary.md): Gets the point along the boundary of the triangle. The triangle boundary has a domain [0, 3] where each subsequent unit domain maps to a different edge.
- [PointAtBarycentricCoords](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/pointatbarycentriccoords.md): Gets a point within this triangle using barycentric coordinates.
- [PointOnInterior](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/pointoninterior.md): Gets the point on the triangle using the AB and AC primary axes.
- [ToMesh](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/tomesh.md): Create a mesh from this triangle.
- [ToPolyline](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/topolyline.md): Create a polyline from this triangle.
- [Transform](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/transform.md): Transform this triangle.
- [TrySmallestEnclosingTriangle](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/trysmallestenclosingtriangle.md): (static) Attempt to create the smallest triangle containing a set of planar points.
- [WithA](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/witha.md): Replace the A corner.
- [WithB](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/withb.md): Replace the B corner.
- [WithC](https://developer.rhino3d.com/api/rhinocommon/type/rhino.geometry.triangle3d/withc.md): Replace the C corner.