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# MTLMotionKeyframeData

Geometry data for a specific keyframe to use in a moving instance.

```
class MTLMotionKeyframeData
```

## Overview

An [`MTLMotionKeyframeData`](/documentation/Metal/MTLMotionKeyframeData) instance describes the location of geometry data for a keyframe. The exact type of data can vary, depending on which kind of motion descriptor you create. For an [`MTLAccelerationStructureMotionBoundingBoxGeometryDescriptor`](/documentation/Metal/MTLAccelerationStructureMotionBoundingBoxGeometryDescriptor) instance, the buffer data is a list of bounding boxes. For an [`MTLAccelerationStructureMotionTriangleGeometryDescriptor`](/documentation/Metal/MTLAccelerationStructureMotionTriangleGeometryDescriptor), the buffer data is a list of vertices.

## Topics

### Creating a motion keyframe data instance

[`data`](/documentation/Metal/MTLMotionKeyframeData/data)

Creates a new keyframe object.

### Specifying the keyframe data

[`buffer`](/documentation/Metal/MTLMotionKeyframeData/buffer)

The buffer that holds the geometry data.

[`offset`](/documentation/Metal/MTLMotionKeyframeData/offset)

The offset, in bytes, to the keyframe data.


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