# Geometry Class (Microsoft.DirectX.Direct3D)

How Do I...?

Contains miscellaneous math-related functions.

Definition

Visual Basic NotInheritable MustInherit Public Class Geometry    Inherits Object public abstract sealed class Geometry : Object public ref class Geometry abstract sealed : Object public final abstract class Geometry extends Object

Members Table

The following table lists the members exposed by the object.

Methods

Method Description
BoxBoundProbe Determines whether a ray intersects the volume of a bounding box.
ComputeBoundingBox Computes a coordinate axis-oriented bounding box.
ComputeBoundingSphere Computes a bounding sphere for a mesh.
ComputeTangentFrame Performs tangent frame computations on a mesh. Tangent, binormal, and optionally normal vectors are generated. Singularities are handled as required by grouping edges and splitting vertices.
FresnelTerm Calculates the Fresnel term.
IntersectTri Computes the intersection of a ray and a triangle.
OptimizeFaces Optimizes a set of faces.
OptimizeVertices Optimizes a set of vertices.
SphereBoundProbe Determines whether a ray intersects the volume of a sphere's bounding box.

Inheritance Hierarchy

Object
Geometry

How Do I...?

Compute a Bounding Sphere from a Mesh

This example shows how to generate a simple bounding sphere around a 3-D object, using the Geometry.ComputeBoundingSphere method. A bounding sphere has many possible uses in 3-D graphics; for example, to help test whether one 3-D object intersects with another.

In the following C# code example, a vertex buffer is created from the vertex data of the mesh object. The new vertex buffer is then locked so that Geometry algorithms can be computed on it. The output of the ComputeBoundingSphere is the radius from the center to the farthest extremity of the mesh object. The mesh object is assumed to be a valid mesh loaded with Mesh.FromFile.


[C#]

Vector3 objectCenter = new Vector3();

using (VertexBuffer vb = Mesh.VertexBuffer)
{
GraphicsStream vertexData = vb.Lock(0, 0, LockFlags.None);