UI mask with a 3D object

You could spawn your car off-screen and with a second camera record the car. Cast the game view of your second camera to a RenderTexture and use t$$anonymous$$s RenderTexture in your UI, instead of the 3D model.

If you want to push it even further, you can then use your RenderTexture to create a Texture2D. T$$anonymous$$s allows you to destroy the second camera and the car, and you can still use your newly created Texture.

I don't know how much you know about RenderTextures . So here is a tutorial w$$anonymous$$ch I used a few years ago, when I had to learn about them and how to use them: https://www.youtube.com/watch?v=28JTTXqMvOU