# render(atTime:viewport:commandBuffer:passDescriptor:) Renders the scene’s contents at the specified system time in the specified Metal command buffer. ``` func render(atTime time: CFTimeInterval, viewport: CGRect, commandBuffer: any MTLCommandBuffer, passDescriptor renderPassDescriptor: MTLRenderPassDescriptor) ``` ## Parameters `time` The timestamp, in seconds, at which to render the scene. `viewport` The pixel dimensions in which to render. `commandBuffer` The Metal command buffer in which SceneKit should schedule rendering commands. `renderPassDescriptor` The Metal render pass descriptor describing the rendering target. ## Discussion This method can be used only with an [`SCNRenderer`](/documentation/SceneKit/SCNRenderer) object created with the [`SCNRenderer`](/documentation/SceneKit/SCNRenderer) initializer. Call this method to tell SceneKit to draw the renderer’s scene into the render target described by the `renderPassDescriptor` parameter, by encoding render commands into the `commandBuffer` parameter. When you call this method, SceneKit updates its hierarchy of presentation nodes based on the specified timestamp, and then draws the scene using the specified Metal objects. > Note: > By default, the playback timing of actions and animations in a scene is based on the system time, not the scene time. Before using this method to control the playback of animations, set the property of each animation to , or specify the ``doc://com.apple.scenekit/documentation/SceneKit/SCNSceneSource/AnimationImportPolicy/playUsingSceneTimeBase`` option when loading a scene file that contains animations. --- 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)