<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.11.0 -",
    "tvOS: 9.0.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "ModelIO",
  "identifier" : "/documentation/ModelIO/MDLAsset/vertexDescriptor",
  "metadataVersion" : "0.1.0",
  "role" : "Instance Property",
  "symbol" : {
    "kind" : "Instance Property",
    "modules" : [
      "Model I/O"
    ],
    "preciseIdentifier" : "c:objc(cs)MDLAsset(py)vertexDescriptor"
  },
  "title" : "vertexDescriptor"
}
-->

# vertexDescriptor

The description of the vertex data format to be used for loading mesh data from the asset.

```
var vertexDescriptor: MDLVertexDescriptor? { get }
```

## Discussion

If you specify a vertex descriptor when loading an asset with the [`init(url:vertexDescriptor:bufferAllocator:)`](/documentation/ModelIO/MDLAsset/init(url:vertexDescriptor:bufferAllocator:)-1tchi) initializer, Model I/O  automatically translates mesh vertex data loaded from the asset into the format described by that [`MDLVertexDescriptor`](/documentation/ModelIO/MDLVertexDescriptor) object. If you do not specify a vertex descriptor, or import an asset through other means, this property’s value is `nil`, and Model I/O  loads vertex data in whatever format is stored in the asset file.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)