Want to add an interactive 3D viewer to your Roblox game's GUI? Here's how you can do it with a few simple steps.

First, you'll need to create a ScreenGui element to house your 3D viewer. This can be done in the Roblox Studio by inserting a new ScreenGui under StarterGui. This ScreenGui will act as the container for your 3D viewer.

Next, you'll need to add a Frame element inside the ScreenGui. Resize and position the Frame as needed to create the area where your 3D viewer will be displayed.

Now, it's time to incorporate the 3D model into the GUI. You can do this by utilizing the InsertObject method to add the 3D model of your choice into the Frame. Once inside the Frame, you can manipulate the model's properties, such as size and position, to fit your design preferences.

To make the 3D viewer interactive, you can utilize LocalScript to handle user input. For example, you can use UserInputService to detect when the user clicks and drags the 3D model to rotate it within the GUI.

Lastly, you'll want to ensure that the 3D viewer is properly rendered and updated. You can achieve this by utilizing RenderStepped or Heartbeat in a LocalScript to regularly update the display of the 3D model in the GUI.

With these steps, you can create an engaging and interactive 3D viewer within your Roblox game's GUI. Whether you're showcasing in-game assets or allowing players to view their characters from different angles, a 3D viewer adds an extra layer of immersion to your game. Experiment with different models, interactions, and visual effects to create a unique and captivating 3D viewer experience for your players.