Hi there! You are currently browsing as a guest. Why not create an account? Then you get less ads, can thank creators, post feedback, keep a list of your favourites, and more!
Click the Create menu tab above, then choose the very last item bottom right "Upload Items". Actually I didn't find it very easily either, as it's under a heading called Creator Forums.
"You can do refraction by raymarching through the depth buffer" (c. Reddeyfish 2017)