# Mesh in Unity ## What is Mesh? * Mesh is a **polygon that the Unity makes the image deformation.** * When you open the PSB through the `sprite editor`, the **Unity2D system will create the polygons automatically**.

Mesh will be created automatically by clinking 'Opne Sprite editior'

### When do we need Mesh? * Like a human body, we need to add bones to the image.

* With skeletal animation, you can make all the animations from a single sprite. * When the polygon is defined inside the image, then its vertices can be manipulated to deform the image with the Unity Bone system. ## How to apply Mesh 1\. To create a mesh, you might need to select a `PSB` in your project, when you see the inspector tab. Clicking the `sprite editor` button will show the sprite editor popup window.

2\. Once you get the popup window, you will need to change the `Sprite Editor` to the `Skinning editor`.

3\. You will see the auto-generated mesh when you tap the `Auto Geometry` button. You can also Re-Generate the mesh if you don’t like it. In the options menu, you could choose the **detail of the outline**, **alpha tolerance** and **subdivide**. The options could be different for each image.

4\. Because of the performance, **we recommend you manually adjust all the mashes as much as possible.** For example, you might need to **clean up the useless vertexes**. This will helps you set the bone much easier. You can add or delete the vertexes through the `Create Vertex` button.

(Left) Automatic generated mesh , (Right) Manually adjusted mesh

5\. How to add bone?

Once you have finished your mesh, the next stage is **adding bones**. Click and drag to create the first bone, following your design. Furthermore, if you want to adjust the Weights, click the `Auto weights` button.

A sprite that moves along a bone with a weight applied

6\. **Always, you will need to adjust weights for the vertex.** It’s up to you but remember, no pain no gain 🙂. There are two more useful tools that you can use for adjusting. * The `Weight Slider` will help you if you want to set the value accuracy. * `Weight Brush` would be great if you don’t want to spend much time doing the rigging.