You're blocking ads, which pay for BlenderNation. Read about other ways to support us.

Builds Available with Caustics


fcausticsample.pngMaybe you've heard the whispers in the air of the new features being developed. One of the most noticed by many involves some updates being made to the internal rendering engine. Specifically, the edition of more rendering controls that now allow the creation of caustic effects.

What is a caustic effect? Well first a little ancient history from wikipedia, the word caustic, in fact, comes from the Greek καυστός, burnt, via the Latin causticus, burning. A caustic is in fact the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface.

Many will refer to the caustics created by Blender as fake. But seeing as everything we create in 3D is our own little reality, the changes will allow the simulation of some great effects. These enhancements are being made by RCRuiz and consist of a compilation of changes in lamps and materials to get the fake caustics in Blender internal. One advantage of them being faked is that the rendering speed is much faster. RCRuiz posted an interesting chart showing how he has implemented caustics:


The original post on the development can be found here (in spanish). A Blenderartist thread RCRuiz started can be found here. And of course you'll need a patched build to actually use the caustics and that can be downloaded from graphicall.

And once you download the patched build you might want to check out the video tutorial RCRuiz created. Enjoy!

note: caustics will not be in the 2.44 release.


  1. I don't so much care if SSS and caustics are fakes. As long as they're there and look convincing enough. Great stuff for all of us.
    And as far as I know, most of the SSS we see out there is fake, even if produced with "high end" software.
    Is the caustics going to make it on the next release too?

  2. Fake but speed features with a good mind and imagination are always better than realistical and long time rendering.
    I'm happy to imagine have control on the dramatism of the intensity of the caustic of a wine glass on the future 2.44. :-)

  3. I thought we had caustics for ages!? Is this in the scanline renderer, rather than the internal raytracer?

  4. Quote: But it's not good when so can see so easily that it's fake :(

    Well, faking gives more room for artistic freedom. And if a highly complex shape is casting caustic, there is no practical way to determine if it is fake or an accurate simulation. And simple shapes seems to cast accurate caustics, so for all intent it looks good.
    One question though (I should really ask this in the blender forums...): does this patch allow reflective caustics? Like the heart shaped caustic cast inside a cylinder?

  5. @toontje: I don't think so. It seems the caustic patch result is the same as POV-ray's fake caustic for transparent materials: you'd need photons to do reflective caustics at all, while fake caustic looks like enhancement of the transparent shadows... Perhaps I'm wrong, I didn't try the caustic builds yet ;)

  6. Fake caustics are nice for animations and so, but for rendering stills you'll definitely need real caustics.

    I think I'll wait for the real thing (like already in YafRay).

  7. I asked RCruiz about reflective caustics a couple days ago. He told me exactly the same thing that olivS pointed: that needs photon mapping, so is a completely different approach.
    Reflective caustics are not possible with this technique.
    I'd like to see this patch in 2.44 though.

  8. Lord of the Rings Junkie on

    Or Indigo. :D

    quote from toontje: "And if a highly complex shape is casting caustic, there is no practical way to determine if it is fake or an accurate simulation."

    I disagree. Look at Suzanne in the pic at the top of this page. The 'caustics' are basically just a projection of the Suzanne shape onto the ground with some bright spots. So fake. I don't care that the caustics aren't real, but they should at least look convincing.

  9. Blending BriGuy on

    So what else does a "real" caustic have, aside from the shape projection with really really bright spots, that makes it "appear" real?

Leave A Reply

To add a profile picture to your message, register your email address with To protect your email address, create an account on BlenderNation and log in when posting a message.