---
title: "formInset(by:)"
framework: spatial
role: symbol
role_heading: Instance Method
path: "spatial/rect3dfloat/forminset(by:)"
---

# formInset(by:)

Insets the rectangle by the specified size.

## Declaration

```swift
mutating func formInset(by dXYZ: Size3DFloat)
```

## Parameters

- `dXYZ`: The inset amount.

## Discussion

Discussion This function insets the rectangle by the specified values on each axis. The origin value is offset by the distance specified by the dXYZ parameter. The size is adjusted by (2*dXYZ), relative to the source rectangle. If the width, height, or depth are positive values, then the rectangle’s size is decreased on that dimension.  If width, height, or depth are negative values, the rectangle’s size is increased on that dimension.