---
title: "+=(_:_:)"
framework: spatial
role: symbol
role_heading: Operator
path: "spatial/size3dfloat/+=(_:_:)-6yxe6"
---

# +=(_:_:)

Calculates the size that’s the element-wise sum of a size and a vector and stores the result in the left-hand-side variable.

## Declaration

```swift
static func += (lhs: inout Size3DFloat, rhs: Vector3DFloat)
```

## Parameters

- `lhs`: The first value.
- `rhs`: The second value.