Cycles Rendering speed


(LordOdin) #21

I sent you one already but you didn’t seem to care :joy: I’ll upload this one later when I get on my computer


(Amethyst) #22

I saw the other one, but I forgot to reply to it. The reduction of render times on it wasn’t much though.


(CarlG) #23

Never? That’s grossly over exaggerated. Have a look at this, cinematography breakdown of American Made, by Tom Antos. Also, a lot of “apartments for sale” photos (at least over here) are shot in natural light in combination with practical lights and maybe builtin flash - but not so much highly elaborate lighting setups. Maybe millionaires can afford that kind of shoot when selling their junk, but the average Joe have to rely on that “serial shooter” who shoots maybe several locations per day. Everything I would consider “professional”, even if the elaborate setup likely produce better result.


(PedroCG) #24

Sorry for bringing this thread back up. But “LordOdin” (Awesome name) could you post the scene that you mentioned? I’m also struggling with a similar issue and would appreciate to see what you did.


(LordOdin) #25

Oh wow I reinstalled windows that day and entirely forgot about this thread.

I replaced the portal with an actual light and removed the hdri.
Used simplify AO to fill out the light in the room.
Make the indirect on the walls and the floors simpler with the light path node.

You can take it a step farther and download a blender build with dithered sobol and scrambling distance and make it ~30% faster and cleaner


(PedroCG) #26

Hmmm…I never used anything in those Simplify settings, how do they work and what values are most important?

And what do you mean making it simpler with a light path node?

And I will take a look at that blender build.


(sundialsvc4) #27

CarlG, maybe I used too-strong of a word when I said, “never.” My point is simply that the lighting isn’t what it seems. Even in a natural-light setting, there are usually helpers standing off-camera holding various reflectors. (Springy circular cloth things, usually with gold-colored material on one side but sometimes white.) The camera often drives slave strobes which are put in big “soft boxes.” (The luminance output of the strobe can be precisely set.)

So, as in the interior scene shown above, the photographer is probably going to take steps to at least shape the light, so that, for example, that “concave corner” isn’t going to wind up too dark, or the edge of the cabinet on the (our-)right side of the frame has the same amount of illumination as the walls on the left side. The sun outside a window is intensely bright and it would ordinarily flood that convex-corner with light leaving other areas in too-much darkness “if left to their own devices.” (Good lighting shouldn’t have to care about, nor depend on, the wallpaper.)


“On a sunny day, open the curtains, then, turn off the room lights.” You see a difference. Turn-off the image-improvement goodies in your phone and take a few straight pictures. It’s gonna be hard to produce a well-exposed frame – to get the light-levels arranged properly from the lightest areas of the frame to the darkest. (“Zone 3” to “Zone 7.”) Especially if you tried to include details from the world outside that window.

Unless you shape the light off-camera, judiciously adding light without drawing attention to what you’ve done. And maybe “comping” the outdoor scene into that window-frame with post-production magic.


In similar fashion, then, with Cycles – “use off-screen light sources, soft-boxes,” which don’t actually appear in the scene and wouldn’t be in the actual room. Instead of asking the engine to calculate multiple bounces of the light, decide what looks good and what’s the least-expensive way to get there. Because, that’s what real photographers do: even outdoors, at a model-shoot, somebody’s holding reflectors.

Even though the renderer can mimic many aspects of physical reality, it’s difficult, uncertain and therefore time-consuming. Try to make the solution easy but the results still believable. “Ingrid, fake it!”