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# convertToYUp

An option for whether to transform assets loaded from the scene file for use in a coordinate system where the y-axis points up.

```
static let convertToYUp: SCNSceneSource.LoadingOption
```

## Discussion

The value for this key is an <doc://com.apple.documentation/documentation/Foundation/NSNumber> object containing a Boolean value. The default value is <doc://com.apple.documentation/documentation/Swift/false>.

SceneKit’s physics simulation works best when the y-axis of scene coordinate space corresponds to the “up” direction of the physics world. Some external 3D authoring tools use coordinate systems where a different axis points up. Specify <doc://com.apple.documentation/documentation/Swift/true> for this key to automatically transform all scene elements loaded from the file based on the [`SCNSceneSourceAssetUpAxisKey`](/documentation/SceneKit/SCNSceneSourceAssetUpAxisKey) value stored in the file.

This option has no effect for assets compressed by Xcode. Instead, use Xcode itself to transform coordinate spaces when compressing the assets.

---

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