Mesh.SetBoneWeights

Parameters

Description

Sets the bone weights for the Mesh.

Supports a variable number of bones per vertex. The bone weights for each vertex must be sorted with the most significant weights first. Zero weights will be ignored.

The weights may be stored with less precision than the floating point values passed in, so do not expect to get the exact same values back using GetAllBoneWeights. The minimum precision used is currently 16-bit normalized integers.

using UnityEngine;
using System.Collections;
using Unity.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
        byte[] bonesPerVertex = new byte[4] { 1, 2, 2, 1 };
        BoneWeight1[] weights = new BoneWeight1[6];

        // Vertex 0
        weights[0].boneIndex = 0;
        weights[0].weight = 1;

        // Vertex 1
        weights[1].boneIndex = 0;
        weights[1].weight = 0.5f;

        weights[2].boneIndex = 1;
        weights[2].weight = 0.5f;

        // Vertex 2
        weights[3].boneIndex = 0;
        weights[3].weight = 0.5f;

        weights[4].boneIndex = 1;
        weights[4].weight = 0.5f;

        // Vertex 3
        weights[5].boneIndex = 1;
        weights[5].weight = 1;

        var bonesPerVertexArray = new NativeArray<byte>(bonesPerVertex, Allocator.Temp);
        var weightsArray = new NativeArray<BoneWeight1>(weights, Allocator.Temp);

        mesh.SetBoneWeights(bonesPerVertexArray, weightsArray);

        // 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");
    }
}

See Also: allBoneWeights, bonesPerVertex, ModelImporter.maxBonesPerVertex, QualitySettings.skinWeights.