4th that!
I know that there are caustics all over the place, but how often have you heard a client say that they want more caustics..?
-Tom
They’ve never asked me for GI or area shadows or blurry reflections either, but they know when “something isn’t right” / “it doesn’t look real”. Those are the details that help sell the image. It’s not that the clients ask for these things, but their brains let them know if something looks real or not.
Right, but it’s not about the clients, it’s about us (well many of us) with the insatiable need to recreate reality and in the end the clients appreciate a more realistic image even if they don’t know why it is.
edit, should of read further before posting. Well put CCS. 
guys in simple terms: its better to have it there and not use it, then not to have it at all.
amen
So some tips on how to enable these in RC3:
(*) Go to the maxscript listener and type “renderers.current.caustics_showCalcPhase=true” without the quotes. This will cause the photon tracing progress to be directly mapped on the image and re-used for the final rendering;
(*) Only directly visible caustics can be visualized in this way. Caustics visible through reflections/refractions will appear in the normal (interpolated) way.
(*) If you are tracing lots of photons, set the Max. density parameter for the caustics to something other than 0.0 as otherwise you’ll get memory overflow.
(*) There are limitations on how this works - e.g. it will not work well with DOF and/or motion blur.
(*) This option is experimental. There is no guarantee that it will be present in future versions in the same form.
(*) This option requires additional memory. It may be quite a lot, depending on the image resolution.
Best regards,
Vlado
thanks for the Tips !
thanks for the pointer vlado. time to test it out
BTW - great to test it 
Thx vlado!
I won’t let this thread die!
Well, any progress ?
Would love to save calculated solution and reuse it, so that it still render in that “unbiased” way 
One way to do this is to split the rendering into elements; the caustics will go in their own element, so you can composite them later on.
With this method, caustics are splatted directly on the screen, so it a very view-dependent method and it is not possible to reuse them in the same way as a normal caustics photon map.
Best regards,
Vlado
Hm. Can then interpolation of saved map be slightly noisier, but more detailed ? Like the picture I get when turning this experimental option on ?
have you done any images with this paul?
Yes, of course. To do this, set the Max. photons option to 0, and set the search distance to match approximately the size of a pixel or two. However, to get a smooth coverage you will need many, many, many photons. It is how I did this picture, for example, where all lighting is done with photons:
In general, this looks like the most robust method for taking into account all light transport paths - indeed, the only one that can do the caustics-in-mirrors effects efficiently, so we’ll be doing more research in this direction…
Best regards,
Vlado
looking good vlado
One thing i noticed is that it takes in account the un-smoothed normal.
In the case of a simple default sphere, i get some really interesting patterns around the main burn, due to the tracer correctly bending light rays per poly…
An option to take into account smoothed normals may be helpful, if it’s at all possible with this method.
Lele
vlado
Ok. Will try that
jacksc02
Well, all my tests so far >
Nice one, Paul!
I was wondering how this is tied to the PPT, and lol…
It seems if i have caustics on (using this method) and turn ppt on as a second pass, the search distance in the caustics tab somewhat drives how the ppt sees the pre-traced caustics…
Being search dist. an absolute value, it’s like trying to set the ppt sample size in world units…
So funny to toy with…
Lele
Forget caustics…more Cow Bell!