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# motionKeyframeCount

The number of keyframes in the geometry data.

```
var motionKeyframeCount: Int { get set }
```

## Discussion

The default value is `1`. If the value is greater than `1`, all geometry descriptors that you attach to this descriptor need to be motion descriptors, and each needs to have exactly that many [`MTLMotionKeyframeData`](/documentation/Metal/MTLMotionKeyframeData) objects.

## See Also

[`geometryDescriptors`](/documentation/Metal/MTLPrimitiveAccelerationStructureDescriptor/geometryDescriptors)

An array that contains the individual pieces of geometry that compose the acceleration structure.


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