# Week 5
1. Basic skinning
- Cylinder skinning
- Using Visor
2. Creating joint chains for lower arm and practice skinning
3. Editing skin weights
- Project 1
Joints are given an influence over the vertices near to them. As a joint rotates, it deforms the vertices it has influence over. The process of defining which vertices are manipulated by which joints is called skinning.
Creating the joints themselves and building handles to manipulate those joints is referred to as rigging.
# Basic skinning
Let's prepare a simple cylindrical mesh and simple joint chains to practice, and do experiments in order to get to know the basics of skinning.
## Cylinder skinning
1. Create a cylinder and change its height and subdivision level from its input node (at the right side of window).
2. Duplicate it and move it using 'snap to grid'.
3. Create a joint chain at the center of the cylinder (you can turn on X-ray joints from teh Viewport / Shading / X-ray joints).
### Experiment 1
- Let's change ***the subdivision levels*** and look at how different it looks when you apply *Bind Skin*.
### Experiment 2
- Let's change ***the max influence value*** in the Bind Skin option editor to emulate ***'rigid'*** skin or 'smooth' skin.
Bind Skin: rigid binding emulation. Max influences: 1, Second joint rotate Z: 45.
## Bipeds modeling skinning
Let's move to a hand model to practice further. You can collect a model to which you would like to add a skeleton from **the Visor editor** (Windows > General editors > Visor).
I imported a horse and a wing modeling, adjusting transformations, and then deleting history & combining to make into a single mesh. I also assigned a blinn material to change the color.
We can start with a simpler model, such as an alien hand from the Bipeds folder in the Visor.
### Menu set
Menu sets for building a skeleton and skinning for today's lecture.
### Bind skin
- Prepare the model with a proper position and size.
- Create joint chains and don't forget to properly name the joints.
- Check out whether its local axis is aligned well (you can find how to do from today's lecture note).
- Delete history from the mesh first, then:
- Bind skin
### Analyze and re-bind
- Pose to analyze the binding
If you need to fix the position or local axis then,
- frist, Skin / Go to Bind Pose
- then Skin / Unbind Skin
Now you can move positions of joints or align its local axis (you can find how to do from today's lecture note).
Reference photos of hand gestures
If everything is fine, go to Bind Skin again.
## Editing skin weight
### Paint Skin Weight
- Pose the hand (rotate joints) until finding any unnatural skin morphing.
- Select the body surface and apply 'Skin / Paint Skin Weight' to editing skinning. It employs the Artisan brush interface to set weights interactively.
- First, you need to select specific joint from the paint skin weight editor.
- [Common Artisan Brush Tool Settings](https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/Maya/files/GUID-67B8F095-4A0E-4BAE-938C-CB41B3EBD533-htm.html)
- Repeat the processes -- you can learn by trial and error while trying to understand the concepts.
Once you feel comfortable doing skinning, let's move to a more complex character.
You can find the alien body from the Visor.
### Component editor
Let's open the **component editor** to control skinning.
It gives you control over each vertex precisely and the exact amount of weight it receives.
1. Select the object and go to its vertex component mode.
2. Select vertices and go to 'Smooth Skins' section in the component editor.
- At the right section, you can find the list of vertices.
- At the middle section, you can find how each vertex's weight is distributed to different joints.
- The total weight for each vertex should be 1.
## Related reference
- [Painting Weights and Skinning: A Straighforward Approach by Kiel Figgins](http://www.3dfiggins.com/writeups/paintingWeights/) - This document covers: the importance of joint placement, creating a low resolution mesh to weight, transferring those weights back to the high-res mesh, additional time saving tools for weighting and mirroring weights, and other useful tips and information.
- [ABOUT MAYA JOINT ORIENT by Rigging Dojo](http://www.riggingdojo.com/2014/10/03/everything-thought-knew-maya-joint-orient-wrong/)
## Next class
Creating a skeleton and a rig (using HumanIK Controls window).