---
title: "setObjectBytes(_:length:index:)"
framework: metal
role: symbol
role_heading: Instance Method
path: "metal/mtlrendercommandencoder/setobjectbytes(_:length:index:)"
---

# setObjectBytes(_:length:index:)

Creates a buffer from bytes and assigns it to an entry in the object shader argument table.

## Declaration

```swift
func setObjectBytes(_ bytes: UnsafeRawPointer, length: Int, index: Int)
```

## Parameters

- `bytes`: A pointer to argument data the method copies to an doc://com.apple.metal/documentation/Metal/MTLBuffer and assigns to an entry in the object shader argument table for buffers.
- `length`: The number of bytes the method copies from the bytes pointer.
- `index`: An integer that represents the entry in the object shader argument table for buffers that stores a record of the doc://com.apple.metal/documentation/Metal/MTLBuffer the method creates from bytes.

## Discussion

Discussion The method is equivalent to creating an MTLBuffer instance that contains the same data as bytes and calling the setObjectBufferOffset(_:index:) method. However, this method avoids the overhead of creating a buffer to store your data; instead, Metal manages the data. important: Only call this method for single-use data that’s smaller than 4 KB. For data that’s more than 4 KB, create an MTLBuffer instance and pass it to setObjectBuffer(_:offset:index:).

## See Also

### Assigning buffers for object shaders

- [setObjectBuffer(_:offset:index:)](metal/mtlrendercommandencoder/setobjectbuffer(_:offset:index:).md)
- [setObjectBuffers(_:offsets:range:)](metal/mtlrendercommandencoder/setobjectbuffers(_:offsets:range:).md)
- [setObjectBufferOffset(_:index:)](metal/mtlrendercommandencoder/setobjectbufferoffset(_:index:).md)