---
title: parentIndex
framework: realitykit
role: symbol
role_heading: Instance Property
path: realitykit/meshresource/skeleton/joint/parentindex
---

# parentIndex

The index of this joint’s parent, or nil if this joint has no parent.

## Declaration

```swift
var parentIndex: Int?
```

## Discussion

Discussion If the joint has a parent, the index of the parent needs to be lower than that of the child.