> For the complete documentation index, see [llms.txt](https://jorge-jgnz94.gitbook.io/hptk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jorge-jgnz94.gitbook.io/hptk/master/modules/avatar/part/hand.md).

# Hand

![](https://2698598769-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MYpeL-Cll-FXMj9b3XC%2F-MZg3Tq6HxifYzmKZHbZ%2F-MZgBBYktCzjEiElxcPe%2Fhand.PNG?alt=media\&token=2bec03ab-f75a-444a-8daa-dbb7fef8b23c)

## Extended SubModel <a href="#model" id="model"></a>

A hand is a specific type of part. HandModel inherits from PartModel. Therefore, it contains extra variables that are described bellow:

#### References

* **Bones:** Wrist bone.
* **Parts:** Thumb, index, middle, ring and pinky fingers.
* **Points:** Palm points, ray and midpoints.

#### Palm points

* **Palm center:** Most interior point of the surface of the hand. For both hands:
  * **Right** direction (red) goes from palm center to wrist.
  * **Up** direction (green) goes from palm center to thumb knuckle.
* **Palm normal:** Point that shares same position as palm center but with different rotation. For both hands:
  * **Forward** direction (blue) matches normal vector of palm surface.
* **Palm exterior:** Palm line point under pinky knuckle.
* **Palm interior:** Palm line point under index knuckle.
* **Pinch center:** Midpoint between thumb tip and index tip.
* **Throat center:** Midpoint between thumb knuckle and index knuckle.
* **Ray:** Point where forward vector of each of its representations represents the direction the hand is pointing towards.

## Extended SubView

HandView offers two functions to toggle hand visuals and physics:

* SetHandVisuals (bool enabled, string representationKey)
* SetHandPhysics (bool enabled)