---
title: "start(endpoint:parameters:viewerOptions:)"
framework: spatialpreview
role: symbol
role_heading: Instance Method
path: "spatialpreview/usdpreviewsession/start(endpoint:parameters:vieweroptions:)"
---

# start(endpoint:parameters:viewerOptions:)

## Declaration

```swift
nonisolated(nonsending) final func start(endpoint: SpatialPreviewEndpoint, parameters: USDPreviewSession.OptimizationParameters = .processed([.optimized, .compressed]), viewerOptions: USDPreviewSession.SpatialViewerOptions = .default) async throws
```