Is there - like with refractive caustics - any workaround available that would deliver sharp reflective caustics like in these examples?
https://www.google.com/search?q=reflective+caustics&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiEu4bQ1LjhAhUOEVAKHWYyAAkQ_AUIDigB&biw=1875&bih=767