Rendering on background image with shadows

Hello,

I am wondering what the best way to make a rendering on a background image and keep the shadows. I know there was a way of doing it with Flamingo, but I don’t have access to that. I do have illustrator though so if I could export it with the shadows and put it on the background image externally that would be ok too.

Thanks

Rhino WIP for Mac can do that with the Raytraced mode and -ViewCaptureToFile.

Here a quick donut model on a random image plucked from the internet. Sun and Skylight enabled, shadow is retained