---
title: Shaping a Physics Body to Match a Node’s Graphics
framework: spritekit
role: article
role_heading: Article
path: spritekit/shaping-a-physics-body-to-match-a-node-s-graphics
---

# Shaping a Physics Body to Match a Node’s Graphics

Shape a physics body to your graphics for the right blend of collision accuracy and performance.

## Overview

Overview In most cases, a physics body should have a size and shape that closely approximates the visual representation of the corresponding node. For example, the rocket shown below has a narrow shape that is not well represented by either a circle or a rectangle. A convex polygon shape is chosen and fitted to match the sprite’s artwork.

Shape a Physics Body Using a Texture’s Alpha Channel If you do not want to create your own shapes, you can use SpriteKit to create a shape for you based on the sprite’s texture. Choose a Simple Geometric Physics Body Shape When choosing a shape for your physics body, do not be overly precise. More complex shapes require more work to be properly simulated. For volume-based bodies, use the following guidelines: A circle is the most efficient shape (init(circleOfRadius:)) A path-based polygon is the least efficient shape, and the computational work scales with the complexity of the polygon (init(polygonFrom:)) Use Edge-Based Physics Bodies Only When Needed An edge-based body is more expensive to compute than a volume-based body. This is because the bodies it interacts with can potentially be on either side of an open edge or on the inside or outside of a closed shape. Use these guidelines: Lines and rectangles are the most efficient edge-based bodies (init(edgeFrom:to:) and init(edgeLoopFrom:)) Edge loops and edge chains are the most expensive edge-based bodies, and the computational work scales with the complexity of the path (init(edgeLoopFrom:) and init(edgeChainFrom:)).

## See Also

### Creating a Body from a Texture

- [init(texture:size:)](spritekit/skphysicsbody/init(texture:size:).md)
- [init(texture:alphaThreshold:size:)](spritekit/skphysicsbody/init(texture:alphathreshold:size:).md)