How to get faster caustics with V-Ray - Tutorial | Cg Blog

How to get faster caustics

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Do you remember how easy is Caustic setup? I talked about in this post: V-Ray caustics in the pool.

With exterior pool is easy getting nice caustics because we have a strong and focused light: the sun. How to achive a similar result using a diffuse light like V-Ray light?

It’s really hard. V-Ray light shoots photons everywhere (at 180°) so we need a looot of subdivisions to get a valuable result.

Lots of subdivisions means lots of time: 20.000 subdivisions need around 10mins to render this simple scene (left image). But there’s a trick to render this scene in few seconds!

Free sample Premium content.

Split light and caustics in 2 different sources:

  • a V-Ray light for normal lighting
  • a standard Spot Light just for caustics

The spot light is perfect to focus caustics in a specific area. Above you can see the image on the right, rendered in only 13 seconds. It’s pretty the same way that Ricardo Eloy in this tutorial, I just changed some little thing and did it in few minutes.

Of course this is a sort of fake solution, because diffuse lights can’t produce strongs caustics. Anyway this method can help us to get a really nice effect.

Watch the video, download the file below and complete the exercise!



  1. Disable caustics for V-Ray light
  2. Add spot light (multipl. 1.000.000) and exclude everything
    ( Make V-Ray light invisible if the spot is behind it )
  3. Enable caustics
  4. Clic render and wait few seconds 🙂


Now, download this file and repeat the exercise.
For any doubts check the “FINAL” version file.

Enjoy it.

/ Also Learn Corona Renderer

12 Responses

  1. Anna says:

    Thank you!

  2. thezagroom says:

    the video not working !

    • Ciro Sannino - Auth says:

      I checked with Firefox, Chrome, Opera and Explorer 64 bit and it works fine 🙂

      Did you tried with others browsers?
      Did you checked some security filter?

    • Zabi says:

      Try to install flash player, from

  3. 3ddd-lv says:

    Perfect!!!! that’s great idea… thank you!

  4. Aurelie says:

    The video is amazing… simple and effective!
    I tried the files and everything is good.

  5. inner says:

    thank you ciro

  6. Aek says:

    Thank you for tutor it very good.

  7. qidangui says:

    And let me learn! thank you……

  8. Kaoru says:

    Thank you again for a great tutorial!

  9. Huzef says:

    Thank sir=, tutor it very good.
    please give me interior lighting in Vray setting

  10. spyros says:

    you are a GOD

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