Provided herein are systems and methods for implementing visual content previews for content items associated with a software application. The content preview includes a visual preview of a content item that is updated based on modifications to the application source code. The content preview includes a plurality of viewports, with each viewport being independently controllable. Each viewport of the content preview can be “paused” to prevent the viewport from updating in response to modifications of the source code, while the content previews associated with other viewports are modified with modification to the source code. In this way, a developer can visually compare different versions of a content item when developing content in the preview application. The device displays a bounding volume concurrently with the content preview to visually depict a relationship between the size of content item and the three-dimensional size of a three-dimensional environment associated with the software application.