The default environment is a professional photo studio with a soft light, but you can change it to more complex ones, like a warm summer lawn.
You can also use your own reflection image. Drag in a 2:1 image (e.g. 2000x1000) onto the background. You can change the background color and keep the reflection.
If you add a 3D background, Rotato will automatically use that background as reflections, too