Hi,I am still trying to get continuously update tracinng line to work. (re: https://forums.developer.apple.com/thread/62727)Using SCNSceneRednerDelegate, I successfully rendered a drawing using Metal APIBut after a brief moment, the rendering is replaced by the objects from SceneKit.Following is my rendering code: func renderer(renderer: SCNSceneRenderer, willRenderScene scene: SCNScene, atTime time: NSTimeInterval) { guard let vm = self.viewModel, let traceModel = vm.traceModel.value, let renderPipeState = traceModel.renderPipeLineState, let nextDrawable = (self.sceneKitView.layer as? CAMetalLayer)?.nextDrawable() else { return } let commandBuffer = traceModel.commandQueue.commandBuffer() let renderPassDescriptor = MTLRenderPassDescriptor() renderPassDescriptor.colorAttachments[0].texture = nextDrawable.texture renderPassDescriptor.colorAttachments[0].loadAction = .Clear renderPassDescriptor.colorAttachments[0].storeAction = .Store let encoder = commandBuffer.renderCommandEncoderWithDescriptor(renderPassDesc