Mesh.boneWeights

Description

The bone weights for each vertex in the Mesh, up to a maximum of 4.

The size of this array is either Mesh.vertexCount or zero. The array is sorted by vertex index.

This property uses BoneWeight structs, which represent exactly 4 bone weights per vertex. Within each BoneWeight struct in the array, the bone weights are in descending order and add up to 1. If a vertex is affected by fewer than 4 bones, each of the remaining bone weights must be 0.

To work with more or fewer bone weights per vertex, use the newer Mesh.GetAllBoneWeights and Mesh.SetBoneWeights APIs, which use BoneWeight1 structs.

See Also: Mesh.GetAllBoneWeights, Mesh.SetBoneWeights, Mesh.GetBonesPerVertex, Mesh.GetBoneWeights, ModelImporter.maxBonesPerVertex, QualitySettings.skinWeights, SkinnedMeshRenderer.quality.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    void Start()
    {
        gameObject.AddComponent<Animation>();
        gameObject.AddComponent<SkinnedMeshRenderer>();
        SkinnedMeshRenderer rend = GetComponent<SkinnedMeshRenderer>();
        Animation anim = GetComponent<Animation>();

        // Build basic mesh
        Mesh mesh = new Mesh();
        mesh.vertices = new Vector3[] {new Vector3(-1, 0, 0), new Vector3(1, 0, 0), new Vector3(-1, 5, 0), new Vector3(1, 5, 0)};
        mesh.uv = new Vector2[] {new Vector2(0, 0), new Vector2(1, 0), new Vector2(0, 1), new Vector2(1, 1)};
        mesh.triangles = new int[] {0, 1, 2, 1, 3, 2};
        mesh.RecalculateNormals();

        // Assign mesh to mesh filter & renderer
        rend.material = new Material(Shader.Find("Diffuse"));

        // Assign bone weights to mesh
        // We use 2 bones. One for the lower vertices, one for the upper vertices.
        BoneWeight[] weights = new BoneWeight[4];

        weights[0].boneIndex0 = 0;
        weights[0].weight0 = 1;

        weights[1].boneIndex0 = 0;
        weights[1].weight0 = 1;

        weights[2].boneIndex0 = 1;
        weights[2].weight0 = 1;

        weights[3].boneIndex0 = 1;
        weights[3].weight0 = 1;

        // A BoneWeights array (weights) was just created and the boneIndex and weight assigned.
        // The weights array will now be assigned to the boneWeights array in the Mesh.
        mesh.boneWeights = weights;

        // Create Bone Transforms and Bind poses
        // One bone at the bottom and one at the top
        Transform[] bones = new Transform[2];
        Matrix4x4[] bindPoses = new Matrix4x4[2];

        bones[0] = new GameObject("Lower").transform;
        bones[0].parent = transform;
        // Set the position relative to the parent
        bones[0].localRotation = Quaternion.identity;
        bones[0].localPosition = Vector3.zero;

        // The bind pose is bone's inverse transformation matrix
        // In this case the matrix we also make this matrix relative to the root
        // So that we can move the root game object around freely
        bindPoses[0] = bones[0].worldToLocalMatrix * transform.localToWorldMatrix;

        bones[1] = new GameObject("Upper").transform;
        bones[1].parent = transform;
        // Set the position relative to the parent
        bones[1].localRotation = Quaternion.identity;
        bones[1].localPosition = new Vector3(0, 5, 0);
        // The bind pose is bone's inverse transformation matrix
        // In this case the matrix we also make this matrix relative to the root
        // So that we can move the root game object around freely
        bindPoses[1] = bones[1].worldToLocalMatrix * transform.localToWorldMatrix;

        // assign the bindPoses array to the bindposes array which is part of the mesh.
        mesh.bindposes = bindPoses;

        // Assign bones and bind poses
        rend.bones = bones;
        rend.sharedMesh = mesh;

        // Assign a simple waving animation to the bottom bone
        AnimationCurve curve = new AnimationCurve();
        curve.keys = new Keyframe[] {new Keyframe(0, 0, 0, 0), new Keyframe(1, 3, 0, 0), new Keyframe(2, 0.0F, 0, 0)};

        // Create the clip with the curve
        AnimationClip clip = new AnimationClip();
        clip.SetCurve("Lower", typeof(Transform), "m_LocalPosition.z", curve);

        // Add and play the clip
        anim.AddClip(clip, "test");
        anim.Play("test");
    }
}