Mia_mat Caustics

As far as generating caustic patterns, there are a few things that I need to setup, two of the most obvious ones are, telling the mia_mat to use caustics instead of transparent shadows and turn on caustics in the MR render settings. On the caustic settings, I usually take the ol' cheapo route of lowering caustic accuracy to say about 20 or 30 and use the cone filter, this enables me to get sharper patterns without having to juice up the photon count emitted from the light too much.

Speaking of the devil, my photon emitting lights are usually spotlights. Why? you ask, because then you can funnel photons where you need them and only where you need them, you wouldn't stand across a room and fling milk from your carton into your bowl of cereal would you? Sure, a little might make it onto the cereal but most of it will end up on your counter top and floor, totally wasted, if the milk even makes it that far in the first place. So, to cut down on some of the trial and error I get the light right up close, so close its almost molesting the objects (this lessens the chance of photons dying off before they hit the subjects) and input an insanely high photon intensity or a really low exponent (.1 is plenty crazy), either way, put on your sunshades, because if caustics are in business we won't be able to miss them. If there still aren't any caustic patterns, then the shading groups on the materials need to be checked to ensure there is a photon shader in the photon shader slot, which in the case of the mia_mat, it would be that very shader slipped in there.

And that's pretty much my caustics checklist, after that it's just a matter on tuning and tweaking Bah, I'm going to stop my babbling here, I need to sleep.

Edit:  Commenter Viktore pointed out I forgot to add a minor but quite important detail.  Turn the intensity of the light down to 0 as you only want the photons and not the extra illumination.



  1. Great glass material and lovely lighting! - Jacques

  2. hey genny very resourcefullblog

  3. Just would like to add:

    When using a light (spot light in this case) for the sole purpose of emitting photons, don't forget to turn off that light's intensity to 0!

  4. Thanks Raphael :)

    Good point Viktore, I completely forgot to say that lol, I'll add it now.


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