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Demo: Indirect Lighting in Blender 2.5 Alpha 1


Here's a short demonstration video of indirect lighting in Blender 2.5 Alpha 1. There are no lights in these scenes - all light is emitted by the geometry.

jason7 wrote:

I wanted to test the new indirect lighting feature in alpha 1 so i create some
scenes and combined them in this video.

No lights were used in any scene. All light comes from geometry and having indirect lighting turned on. Renders took an average of 10sec per frame at 720p.

There is this related thread where I share settings and captures.


About the Author

Avatar image for Bart Veldhuizen
Bart Veldhuizen

I have a LONG history with Blender - I wrote some of the earliest Blender tutorials, worked for Not a Number and helped run the crowdfunding campaign that open sourced Blender (the first one on the internet!). I founded BlenderNation in 2006 and have been editing it every single day since then ;-) I also run the Blender Artists forum and I'm Head of Community at Sketchfab.


  1. If you stay in an unlit room for too long, things start to sort of glow -best visualization example: imagine a fluorescent lamp with dirt on it. I guess that's one use for indirect lighting :D -filming people in the dark lit by the diffusion of light from the dusk sky :) <.< ok, meybez too much info?

    -*loves indirect lighting* *and the demo*

  2. Vending: Indirect lighting happens anywhere, if you have shadow or diffuse colour bleed :)
    No need to limit it to mesh-lights only. ^^

    And I also like the demo a lot :)

  3. One of the coolest things I've seen in a while. Now I just need an excuse to use it, shouldn't be too hard to find something. ;-)

  4. I've been playing with the settings for a while now, and I like mesh lighting a lot. There seem to be two important features missing, though. Does anybody know what's still to come?

    -Mesh lights don't seem to cast shadows. It seems like soft shadows are an inherent feature of ambient occlusion, but I'm not seeing the light emitted from meshes being blocked by non-emitters. Am I wrong?

    -Light bleeds beautifully from emitter meshes onto surrounding objects, but then it stops. Is there / will there be a way to extend color bleeding to non-emitting meshes?

    Thanks for the demo, Jason7. It was cool.

  5. Sorry, but as far as i can see there's no indirect light in this video.
    There's just direct light (from meshes).

    Direct light: emitter -> surface -> cam.
    Indirect light: emitter -> surface -> surface -> ... -> cam

  6. I second Dundee...

    The term "Indirect" lightning refers to the light that bounces off from a material. It's called indirect because the light that comes from that material is not produced by it, it's just bouncing from it...

    I quote from

    Indirect Lighting

    (Term of lighting design)

    Lighting provided by reflection usually from wall or celiling surfaces. In daylighting, this means that the light coming from the sky or the sun is reflected on a surface of high reflectivity like a wall, a window sill or a special redirecting device. In electrical lighting the luminaires are suspended from the ceiling or wall mounted and distribute light mainly upwards so it gets reflected off the ceiling or the walls.

    Just to get the concepts right and be on the same page when we talk about it...

  7. Dundee is correct - this is indeed a part of what most people consider to be GI, but it's not indirect - it's more realistic though than using lamp objects only. And yes, it seems no shadow casting (yet?) - that would slow things down a lot more.
    Great video project though - like the simple style and use of particles.

  8. That is so AWESOME :D

    awesome, awesome, awesome :) wow, the glow is amazing, it is so cool...

    i'm SO gonna try Mesh Lighting

  9. I played with it a bit, but then I left it because it is just mesh lights, no real indirect lighting. It could be something much better if you didnt have to turn on the "emit" parameter, but I guess it has some drawbacks, and it wouldn't replace real Indirect lighting. Let's see an example:

    you have a red plastic ball on a white matte floor. If you have good day illumination (doesn't have to be direct sunlight although it would be more noticeable) some colour bleed will occur, and the white floor will be tinted red under the ball.

    This could be easily implemented with the current iteration of "indirect lighing" in blender 2.51, but...

    Now suppose you have a white painted room, all white except one wall that is painted red. If direct sunlight reaches certain area of the wall, colour bleed will occur, but only reflected from the zone of the wall hit by sunlight.

    This I guess couldn't be implemented in the current iteration of "Indirect lighting" and would imply much more complicated calculations it would need a full GI render motor.

    But as I said if only you haden to turn on "emit" it'd be much more usefull.

  10. @Dundee: Well in fact it is blenders indirect lighting, just because the objects emit the light itself its not visible.
    For example if the pillars in one of the scenes had only the red color (and no emiting), you would se a semi-realistic AO bouncing effect with a red color.

    Please remember, its not real indirect lighting as it uses Ambient Occulsion for its calculating. Also for now its very limited (at least in 2.5 Alpha 1) because it can only be used if AO is set to aproximate (i hope they implement also the raytracing feature or i won't be able to use this feature or they allow to use also normal raytracing AO) and only the first light bounce uses the color of the material.

  11. Even with only direct lighting this is pretty cool. How is it done, is there a light per vertex, or some sort of area light per poly? Forward or deferred render?

  12. As many others mentioned, there doesn't seem to be any indirect lighting, since
    a- it needs an emit value and light objects are ignored
    b-there's no color bleed from non emiting materials

    If we are not mistaken This looks like better suited as a material properties option for "illuminate other objects" under emit value.

    I hope someone of the team will be able to explain us how this could be used to get any result that would'nt be worse than the previous radiosity solution that existed and which has been removed. Lightcuts also seemed to get better results, by the way.

  13. @Marcus:

    The way this animation was done:

    Create cone object, and half a sphere. Duplivert the Cones on the sphere.

    Create a smaller sphere.

    Add 'Cast' modifier to half-sphere, make the smaller sphere the object that affects the cast modifier.

    It would be simpler to just show you a blend file, I have included a working rig:

    Enjoy :)

    edit: Move the small sphere around to see the effect.

  14. So, the difference between this and radiosity is what now? If I'm not mistaken, radiosity actually has indirect lighting, which this certainly does not. This post is mislabeled. I'm not sure what the point of this was...

  15. It looks like all of the comments before mine were positive... I'm sorry if I changed the tone of the discussion. That wasn't my intention, as this is very cool, and mesh lights are an awesome feature even on their own.

  16. Cory A. Taylor on

    If the indirect lighting works so well and renders fast, I can not think of a good reason to use normal lamps outside of effects.

  17. Graphicall have link to Indirect Lighting teasers pictures
    but give some test to animation scene please,Mr. code man.

  18. Indirect lighting is there. You can even define the number of indirect bounces. Look up your blender 2.51 before posting comments, people...It's working if you enable approximate ambient occlusion for now(not raytrace).

    And yes, shadows are still not there, however i think they plan to do it.

  19. I dunno much about direct or indirect lighting, to me, it just looks like the Emit material has gotten a new term. I haven't played with indirect lighting yet, but will soon. Hopefully it's faster than the old Emit material, which seemed to take forever...

  20. Indirect Lighting works, but needs to have rather strong Factor and some bounces, also it looks a bit weird (flat or not so realistic) so a little of environmental lighting and ambient oclusion is needed to make it look better, I also changed to shadow color so it wasn't pitch black, here is a picture:

    There is only one spotlight source, as you may see there is light in the upper part inside the "building", that bounces from the floor.

  21. Hi,

    Can some body guide me?

    Blender 2.5 not running on my PC. My configuration is
    AMD 2600 processor
    RAM 1 gb+256 MB two chips
    No graphics card

    If i upgrade to

    Graphics card 512 MB
    RAM 2 GB

    will blender 2.5 run or I have to go for a new PC with better graphics card altogether?

    Please can somebody guide me?

  22. brilliant video! very stylish indeed!

    good to finally see some advanced rendering for blender out of the box

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