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Using Portals to Accelerate your Render Times


Andrew Price shows the impact of light portals and how to use them.

Interior scenes are notorious for taking a ridiculously long time to render – just two years ago I was working on a scene that took an entire month to render. But if I were to render that scene today using portals, it would have finished in a fraction of the time.

Portal lamps are a new feature in Blender 2.75 that help Blender understand your scene, and thus speed up rendering significantly.

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. Wow amazing intuitiv mini tutorial...
    Often a missing feature in Tutorials and this a mega good demonstration or animation and not only a crappy greace pencil picture of how the math perform in a Visual well simple but effectiv way and this is so super idea the bouncing Rays & Portals.


    Best regard

  2. Another quick and clear tip from Andrew... but no! he accidentally left the radio playing in the background! That's the first time I've ever known Andrew make that mistake. Please could you turn off the background noise before recording your next tutorial?

  3. How can it "know" in advance which rays from the camera will end up bouncing into the portal? Doesn't it just kill off the rays that haven't hit it after a certain number of bounces?

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