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Reduce Cycles Noise with Light Portals


Jonathan Lampel writes:

Interior scenes in Cycles are notorious for being really noisy. Here's a quick tip to help clear things up more quickly in the latest version of Blender.

This requires Blender 2.75.


  1. More Noise, Less Noise... Still Noise. Don't use cycles for interiors. It sucks bad. BTW how da hell is possible that someone uses only 10 samples renders to show the difference in noise and time? facepalm

    • I believe you didn't observe more,

      10 samples = is enough to differentiate from the noisy one and it's a big difference

      there's no perfect render without a noise and not only Blender do it that way, even the commercial ones have noises it's just artists are keen enough to lessen the noise in there renders.

      Cycles is already proves it is good for interiors and probably a lot of architects use it too, it just needs time to render, if you got powerful hardware then it's already good.

      • enough =/= optimal.

        I'm not blaming noise itself, but the unacceptable noisy renders made by cycles.
        I've said that it's not made for interiors, portals or not.

        No it's not good for interiors. It's not meant to be good for interiors and so far there are no plans to make it suitable for interiors. Hardware is not the matter obviously.

        • then what do you suggest the users will use then?

          the thing is even the Cycles isn't as perfect as the commercial counterparts like Vray, Octane, Renderman, Keyshot and other renderers. The important part here is it's FREE. Sure you can have commercial ones for free using trials or pirates for personal use, but use it for commercial purpose you will hurt in a long run ...

          Yes I admit, cycles is bad at fireflies but devs keep it on improving it and Kudos to them. And I'm not leaving cycles because of that, Blender is been long for me since I started learning it.

          Maybe for you it's not good for interiors, but many people proved it already that it can be as good as commercial ones, see for yourself at and look for their portfolio / works / galleries in the wilderness ...

          But how can you tell it's not good for interiors? can you show us other than the noise problems?

          And as for the "ask the professionals what tools they use" ...

          In my observations and friends who use commercial ones, it's the tool they use since they started learn 3D and renderings and it's already in them, it can cost them time and money if they have to learn another software but if they have plenty of time and not busy in their works, Blender is open for people who have interested to learn it.

          • Have you or one of your friends ever made interior renders following specific standards? Have you ever had to deal with bosses, deadlines, important clients with high expectations?
            "Study Cycles" is some kind of joke compared to what you need to know about interior lighting and the render engines used by professionists. Probably that's why you can't understand what I say.

            Anyway can I have a bad opionion about cycles for interiors or we all toghether must worship cycles as a gift from god just because it's free? Cycles is not meant to be a render engine for the interior rendering field. This is a fact. Then we can even stun ourself with the "free=good for everything" fairy tale. If I spend 300 bucks and I earn 2500/month, I think I've made a good deal. If I spend 0, and I earn 300-500 bucks... you know... I dont.

  2. Myself i prefer Bilateral-Blur node although it requires extra time to setup (unless you've already created a universal setup) ;-)

  3. A reply to all aside the specific replies that I've made.
    I've said that cycles is not designed for interior renders. If "it sucks bad" offended your sensitivity, well I apologize. Didn't know there were so much fanboys with blind eyes here. It seems that no one can criticize a simple tool without being personally harassed by blind fanboys.
    I suggest you to ask to professionists what tool they use and why, and invite them to use cycles with portals.
    Then we can talk probably.

    God, better if I stay away from here.

  4. I object to people POSTING noisy Cycles renders and asking for feedback. Give me a clean render, THEN I'll comment on your lighting, textures, modeling, etc.

    By the way, artistry has nothing to do with improving the noise in a Cycles render--it is a technical problem.

  5. The portals feature is nicely explained in the video, and does help to focus more light for an interior scene to work with. Here's a further work-around ... Playing with this window-based illumination lighting set-up, I found that, by duplicating the portal (then moving it slightly behind - ie outside) and dechecking it back to a straight area lamp, then setting the lamp illumination at a lowish level, and additionally dechecking the area lamp visibility except for diffuse only in the ray visibility section in the object panel, then the scene has a better range of 'fill' light rays to work with. The area lamp of course needs to be slightly tinted to match the 'outside' environment light or sky.

  6. An error in my last comment above - the low-level area lamp should be slightly in front of the portal.

    Here are some comparative images - renders just at 25 samples for illustration, obviously better with a lot more ...

    No portal, just with environmental sky lighting:

    With portal added:

    With portal and additional low-level area lamp, invisible except for the effect upon diffuse:

    Portal and area 'fill' lamp positioning:

  7. I kinda agree with prostop. Cycles and interiors isn't really a good match except in certain situations. Cycles has still a long way to go.

    Still, portals is good albeit an old technique. Not really groundbreaking nowdays and doesn't really solve the issue much.

    • I love Cycles for what it is, but I agree it's not built for interiors. Fanboys will obviously say different and scream until they're blue in the face.

      There isn't any realistic interior galleries with it either as anyone who knows their salt would say. To illustrate an example, create an interior in Blender and place one 40watt bulb in the room and see how well Cycles performs.

      If you've got money to spend, Vray for Blender works great and is probably the cheapest and quickest solution. I paid £250 for Vray recently and although it doesn't have a preview works perfectly for interiors.

      If you don't understand the difference, then like me, do some more study till you understand the difference. This old discussion should finally be put to bed, it's so tedious!

      It's why the pros don't move to Cycles for Architectural renders, who in their right mind wouldn't go the blender route knowing Blender and Cycles is free? If you run a business you want to save money.

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