# Unity - How to add bones to procedural mesh

Basically this is the set up: An N amount of prefabs are bundled together into a new GameObject. This is then merged into a single main mesh composited of M amount of material submeshes. The shape is standing upwards on the Y axis and is a bunch of arms. The goal is to move these by adding bones.

I wasn't able to find many examples on how to properly assign bones to a procedural mesh which isn't a simple cube.

The problem is assignment of vertices to the boneweights. I'd like for the transform Y=0 vertices to have no weight and the Y=furthest vertices have full weight. I am not sure how the assignment should be done.. Any pointers? :)

So far the Lower and Upper bone transforms are in the right place, but when moving them the mesh isn't bending as I hoped it would in a nice curve, half of the vertices are simply moved uniformly with a thin mesh line connecting the two halves.

private void _AddBones()
{
if(m_SkinnedRenderer != null)
{
// Make bone weight for vertices
BoneWeight[] weights = new BoneWeight[m_MainMesh.vertexCount];
int halfway = (weights.Length / 2);
for (int i = 0; i < weights.Length; i++)
{
if(i < halfway)
{
weights[i].boneIndex0 = 0;
weights[i].weight0 = 1;
}
else
{
weights[i].boneIndex0 = 1;
weights[i].weight0 = 1;
}
}

m_MainMesh.boneWeights = weights;

// Make bones and bind poses
Transform[] bones = new Transform[2];
Matrix4x4[] bindPoses = new Matrix4x4[2];
bones[0] = new GameObject("Lower Bone").transform;
bones[0].parent = m_MergedRoot.transform;
bones[0].localRotation = Quaternion.identity;
bones[0].localPosition = Vector3.zero;
bindPoses[0] = bones[0].worldToLocalMatrix * m_MergedRoot.transform.localToWorldMatrix;

bones[1] = new GameObject("Upper Bone").transform;
bones[1].parent = m_MergedRoot.transform;
bones[1].localRotation = Quaternion.identity;
bones[1].localPosition = new Vector3(0, 1.5f, 0);
bindPoses[1] = bones[1].worldToLocalMatrix * m_MergedRoot.transform.localToWorldMatrix;

m_MainMesh.bindposes = bindPoses;
m_SkinnedRenderer.bones = bones;
m_SkinnedRenderer.sharedMesh = m_MainMesh;
m_SkinnedRenderer.rootBone = bones[0];
}
}

• – Draco18s Jun 5 at 1:24
• @Draco18s Sorry, it's just hard to get help regarding the subject. – Mads M Jun 5 at 4:29