# 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. ## Discussion 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. **Swift:** ```swift let sprite = SKSpriteNode(imageNamed: "Spaceship") sprite.physicsBody = SKPhysicsBody(texture: sprite.texture!, size: sprite.texture!.size()) ``` **Obj-C:** ```objc SKSpriteNode *sprite = [SKSpriteNode spriteNodeWithImageNamed:@"Spaceship"]; sprite.physicsBody = [SKPhysicsBody bodyWithTexture:sprite.texture size:sprite.texture.size]; ``` ### 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:)`](/documentation/SpriteKit/SKPhysicsBody/init(circleOfRadius:))) - A path-based polygon is the least efficient shape, and the computational work scales with the complexity of the polygon ([`init(polygonFrom:)`](/documentation/SpriteKit/SKPhysicsBody/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:)`](/documentation/SpriteKit/SKPhysicsBody/init(edgeFrom:to:)) and [`init(edgeLoopFrom:)`](/documentation/SpriteKit/SKPhysicsBody/init(edgeLoopFrom:)-8sqfy)) - 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:)`](/documentation/SpriteKit/SKPhysicsBody/init(edgeLoopFrom:)-5grxu) and [`init(edgeChainFrom:)`](/documentation/SpriteKit/SKPhysicsBody/init(edgeChainFrom:))). --- Copyright © 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)