I am blender beginner. I found Blender has 2 renders, eevee and cycle. But I also find an Octane render in website. What are the differences among eevee, cycle and octane? Is octane an addon? Is yes, how much?
Well, yes and no. Octane is not for blender only, it's more of an engine in many 3d software. https://render.otoy.com/forum/viewtopic.php?f=7&t=72241#p366488, Octane uses the computer GPU to render, and it is like Cycles but a real-time raytracing, which means its acts like evee but produces renders like cycles. Evee is just a real time render engine which doesn't care about light that much.