Unity has three systems that can be used to build UI. Which you choose will depend on where your UI will be displayed, what you are trying to accomplish, whether you’re working on a pre-existing project, and how comfortable you are with coding.

The UI you build can either be in-game or in-Editor. In-game UI is the UI that can be accessed by your players. In-Editor UI is UI that displays within the Unity Editor and assists with development.

If you want to build UI for your game or application, you can choose between the Unity UI (uGUI) system or the UI Toolkit. If you want to build UI that appears in your Unity Editor, you can use either the UI Toolkit or IMGUI. The following Venn diagram summarizes the uses of the different UI systems:

Figure 5.1: A comparison of in-game and in-Editor UI

Looking at Figure 5.1, you may be thinking, “Well, UI Toolkit works for everything! I’m just going to learn that and be...