To clarify, Rayscaper is commercial software. A license costs $99 or $74.99 for SketchUcation users.
You can use Rayscaper for free, but then it has a watermark over the render. I removed the limitation on rendering size, as I didn't want to spend my energy on crippling the experience in the free version. I still want you to have a great experience, even with the free version, in the hope that that can convince you to support the work and buy a license (which you both did, so thanks for that!). And if you don't want to buy the license, that's cool too.