I was doing some tests with Cycles render. I took one of our studio production scenes that we rendered with 3delight renderman and decided to render it in Cycles. The results were nice out of the box, but always noisy and terribly slow.
As I use Renderman on daily basis at work, I know that the Renderman is so fast because it allows to cheat lots of things, obviously renderman’s lighting is not physically accurate but who cares! As long as the image is done in time and looks beautiful it doesn’t matter if it was done with path tracing or REYES pipeline. So I decided to look for some ways to cheat lighting in Cycles… Good news! I found out that it is possible to cheat lighting in Cycles, just it needs more refinement and some development in this area, hopefully some Cycles developers will get interested in this post and implement some of the features.
So here are some comparisons:
This is GI render with one bounce and 2 lights: one light comes from the window and another is placed in the room to lighten noisy areas. I did not subdivide the geometry…honestly I don’t know how to do it correctly in Blender.
And this image is made with a renderman workflow in mind.
There is one window light without any GI or world background texture. It rendered really fast and as you see it is completely noise free! Obviously this image is not physically accurate and not 100% realistic but it works!
Here I used one light that gave me nice soft shadows from the window and than I introduced AO that acted as a ambiance of the room.
For decades this fake method was abused by renderman artists for cartoons and top blockbuster movies. And it is available in Cycles too…BUT you can get away with even more colorful and photoreal images if the Cycles AO feature implemented IBL. Basically AO is a “local” lighting effect that is just a pure solid white color light that is applied on the exposed geometry, this way you get flat lit scene with some AO shadowing…and an image looks boring! But if the AO sampled the HDRI , the lighting would have all interesting color variations based on the object’s normal direction. That would allow more realistic,fast, noise free and colorful renders.
I hope the AO feature will be extended with IBL functionality or at least there would be a way to change the AO light color to the user specified colors.
Tell me what you think.