Version: 2019.3
LanguageEnglish
  • C#

Mesh

class in UnityEngine

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Inherits from:Object

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Implemented in:UnityEngine.CoreModule

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Description

A class that allows creating or modifying meshes from scripts.

Meshes contain vertex data (Positions, Normals, TexCoords etc.) and "face" data, with faces most often being triangles.

Conceptually, all vertex data is stored in separate arrays of the same size. For example, if you have a mesh of 100 Vertices, and want to have a position, normal and two texture coordinates for each vertex, then the mesh should have vertices, normals, uv and uv2 arrays, each being 100 in size. Data for i-th vertex is at index "i" in each array.

For every vertex there can be a vertex position, normal, tangent, color and up to 8 texture coordinates. Texture coordinates most often are 2D data (Vector2), but it is possible to make them Vector3 or Vector4 if needed. This is most often used for holding arbitrary data in mesh vertices, for special effects used in shaders. For skinned meshes, the vertex data can also contain boneWeights.

The mesh face data, i.e. the triangles it is made of, is simply three vertex indices for each triangle. For example, if the mesh has 10 triangles, then the triangles array should be 30 numbers, with each number indicating which vertex to use. The first three elements in the triangles array are the indices for the vertices that make up that triange; the second three elements make up another triangle and so on.

Note that while triangle meshes are the most common use case, Unity also supports other mesh topology types, for example Line or Point meshes. For line meshes, each line is composed of two vertex indices and so on. See SetIndices and MeshTopology.

Simple vs Advanced Mesh API

The Mesh class has two sets of methods for assigning data to a Mesh from script. The "simple" set of methods provide a basis for setting the indices, triangle, normals, tangents, etc. These methods include validation checks, for example to ensure that you are not passing in data that would include out-of-bounds indices. They represent the standard way to assign Mesh data from script in Unity.

The "simple" methods are: SetColors, SetIndices, SetNormals, SetTangents, SetTriangles, SetUVs, SetVertices, SetBoneWeights

There is also an "advanced" set of methods, which allow you to directly write to the mesh data with control over whether any checks or validation should be performed. These methods are intended for advanced use cases which require maximum performance. They are faster, but allow you to skip the checks on the data you supply. If you use these methods you must make sure that you are not supplying invalid data, because Unity will not check for you.

The "advanced" methods are: SetVertexBufferParams, SetVertexBufferData, SetIndexBufferParams, SetIndexBufferData, SetSubMesh, and you can use the MeshUpdateFlags to control which checks or validation are performed or omitted.



Manipulating meshes from a script

There are three common tasks that might want to use the Mesh API for:

1. Building a mesh from scratch: should always be done in the following order:
a) Assign vertices
b) Assign triangles.

using UnityEngine;

public class Example : MonoBehaviour { Vector3[] newVertices; Vector2[] newUV; int[] newTriangles;

void Start() { Mesh mesh = new Mesh(); GetComponent<MeshFilter>().mesh = mesh; mesh.vertices = newVertices; mesh.uv = newUV; mesh.triangles = newTriangles; } }

2. Modifying vertex attributes every frame:
a) Get vertices
b) Modify them
c) Assign them back to the mesh.

using UnityEngine;

public class Example : MonoBehaviour { void Update() { Mesh mesh = GetComponent<MeshFilter>().mesh; Vector3[] vertices = mesh.vertices; Vector3[] normals = mesh.normals;

for (var i = 0; i < vertices.Length; i++) { vertices[i] += normals[i] * Mathf.Sin(Time.time); }

mesh.vertices = vertices; } }

3. Continously changing the mesh triangles and vertices:
a) Call Clear to start fresh
b) Assign vertices and other attributes
c) Assign triangle indices.

It is important to call Clear before assigning new vertices or triangles. Unity always checks the supplied triangle indices whether they don't reference out of bounds vertices. Calling Clear then assigning vertices then triangles makes sure you never have out of bounds data.

using UnityEngine;

public class ExampleClass : MonoBehaviour { Vector3[] newVertices; Vector2[] newUV; int[] newTriangles;

void Start() { Mesh mesh = GetComponent<MeshFilter>().mesh;

mesh.Clear();

// Do some calculations... mesh.vertices = newVertices; mesh.uv = newUV; mesh.triangles = newTriangles; } }

Properties

bindposesThe bind poses. The bind pose at each index refers to the bone with the same index.
blendShapeCountReturns BlendShape count on this mesh.
boneWeightsThe bone weights of each vertex.
boundsThe bounding volume of the Mesh.
colorsVertex colors of the Mesh.
colors32Vertex colors of the Mesh.
indexFormatFormat of the mesh index buffer data.
isReadableReturns true if the Mesh is read/write enabled, or false if it is not.
normalsThe normals of the Mesh.
subMeshCountThe number of sub-meshes inside the Mesh object.
tangentsThe tangents of the Mesh.
trianglesAn array containing all triangles in the Mesh.
uvThe base texture coordinates of the Mesh.
uv2The second texture coordinate set of the mesh, if present.
uv3The third texture coordinate set of the mesh, if present.
uv4The fourth texture coordinate set of the mesh, if present.
uv5The fifth texture coordinate set of the mesh, if present.
uv6The sixth texture coordinate set of the mesh, if present.
uv7The seventh texture coordinate set of the mesh, if present.
uv8The eighth texture coordinate set of the mesh, if present.
vertexAttributeCountReturns the number of vertex attributes that the mesh has. (Read Only)
vertexBufferCountGets the number of vertex buffers present in the Mesh. (Read Only)
vertexCountReturns the number of vertices in the Mesh (Read Only).
verticesReturns a copy of the vertex positions or assigns a new vertex positions array.

Constructors

MeshCreates an empty Mesh.

Public Methods

AddBlendShapeFrameAdds a new blend shape frame.
ClearClears all vertex data and all triangle indices.
ClearBlendShapesClears all blend shapes from Mesh.
CombineMeshesCombines several Meshes into this Mesh.
GetAllBoneWeightsThe bone weights of all vertices.
GetBaseVertexGets the base vertex index of the given sub-mesh.
GetBindposesGets the bind poses of the Mesh.
GetBlendShapeFrameCountReturns the frame count for a blend shape.
GetBlendShapeFrameVerticesRetreives deltaVertices, deltaNormals and deltaTangents of a blend shape frame.
GetBlendShapeFrameWeightReturns the weight of a blend shape frame.
GetBlendShapeIndexReturns index of BlendShape by given name.
GetBlendShapeNameReturns name of BlendShape by given index.
GetBonesPerVertexThe number of non-zero bone weights for each vertex.
GetBoneWeightsGets the bone weights of the Mesh.
GetColorsGets the vertex colors of the Mesh.
GetIndexCountGets the index count of the given sub-mesh.
GetIndexStartGets the starting index location within the Mesh's index buffer, for the given sub-mesh.
GetIndicesFetches the index list for the specified sub-mesh.
GetNativeIndexBufferPtrRetrieves a native (underlying graphics API) pointer to the index buffer.
GetNativeVertexBufferPtrRetrieves a native (underlying graphics API) pointer to the vertex buffer.
GetNormalsGets the vertex normals of the Mesh.
GetSubMeshGet information about a sub-mesh of the Mesh.
GetTangentsGets the tangents of the Mesh.
GetTopologyGets the topology of a sub-mesh.
GetTrianglesFetches the triangle list for the specified sub-mesh on this object.
GetUVDistributionMetricThe UV distribution metric can be used to calculate the desired mipmap level based on the position of the camera.
GetUVsGets the UVs of the Mesh.
GetVertexAttributeReturns information about a vertex attribute based on its index.
GetVertexAttributeDimensionGet dimension of a specific vertex data attribute on this Mesh.
GetVertexAttributeFormatGet format of a specific vertex data attribute on this Mesh.
GetVertexAttributesGet information about vertex attributes of a Mesh.
GetVerticesGets the vertex positions of the Mesh.
HasVertexAttributeChecks if a specific vertex data attribute exists on this Mesh.
MarkDynamicOptimize mesh for frequent updates.
MarkModifiedNotify Renderer components of mesh geometry change.
OptimizeOptimizes the Mesh data to improve rendering performance.
OptimizeIndexBuffersOptimizes the geometry of the Mesh to improve rendering performance.
OptimizeReorderVertexBufferOptimizes the vertices of the Mesh to improve rendering performance.
RecalculateBoundsRecalculate the bounding volume of the Mesh from the vertices.
RecalculateNormalsRecalculates the normals of the Mesh from the triangles and vertices.
RecalculateTangentsRecalculates the tangents of the Mesh from the normals and texture coordinates.
SetBoneWeightsSets the bone weights for the Mesh.
SetColorsSet the per-vertex colors of the Mesh.
SetIndexBufferDataSets the data of the index buffer of the Mesh.
SetIndexBufferParamsSets the index buffer size and format.
SetIndicesSets the index buffer for the sub-mesh.
SetNormalsSet the normals of the Mesh.
SetSubMeshSets the information about a sub-mesh of the Mesh.
SetTangentsSet the tangents of the Mesh.
SetTrianglesSets the triangle list for the sub-mesh.
SetUVsSets the UVs of the Mesh.
SetVertexBufferDataSets the data of the vertex buffer of the Mesh.
SetVertexBufferParamsSets the vertex buffer size and layout.
SetVerticesAssigns a new vertex positions array.
UploadMeshDataUpload previously done Mesh modifications to the graphics API.

Inherited Members

Properties

hideFlagsShould the object be hidden, saved with the Scene or modifiable by the user?
nameThe name of the object.

Public Methods

GetInstanceIDReturns the instance id of the object.
ToStringReturns the name of the object.

Static Methods

DestroyRemoves a GameObject, component or asset.
DestroyImmediateDestroys the object obj immediately. You are strongly recommended to use Destroy instead.
DontDestroyOnLoadDo not destroy the target Object when loading a new Scene.
FindObjectOfTypeReturns the first active loaded object of Type type.
FindObjectsOfTypeReturns a list of all active loaded objects of Type type.
InstantiateClones the object original and returns the clone.

Operators

boolDoes the object exist?
operator !=Compares if two objects refer to a different object.
operator ==Compares two object references to see if they refer to the same object.

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