saving prepasses / caustics

[dworkind]

i'm doing a render with caustics that is taking WAY longer then i had expected.. i have the 1st prepass and caustic maps saved.. but im in the first quarter of my second prepass and its taking forrrreverrrrr... can i stop the second prepass now, and start rendering from the casutics map and 1st (and part of the second) prepass i already have saved?

[dalomar_cg]

Re: saving prepasses / caustics

Well, yes, if you have finished with the Caustics calculation you can save that solution, change the mode to From File, and then choose your saved map. With IR its not as straight forward. Basically you want to be using Incremental Add to map because you're adding to a solution. This requires having the map in memory, so (assuming that you'll be shutting down SU/your computer) you would have to set the IR mode to From File, load your saved IR map, initiate the render, then cancel it once it actually gets the IR map loaded. This will put the saved map into memory, and then you can change the mode to Incremental Add.

The thing that "bothers" me is that your IR calculations are taking so long to begin with. Are you by any chance rendering at a high resolution? if so, have you adjusted your min/max rates or just left them at what they were when you were rendering smaller images?

[dworkind]

Re: saving prepasses / caustics

my IR calculations are set to min -3 max -2.. i have alot of glass in the view with a pool with a glass floor which is why i need the caustics.. i put one light over the pool and the rest of the light is from GI and default lights. my render size is one of the presets i cant remember the exact size but its closest to the numbers 1600x1200.. ive done this rendering before without the caustics and it took maybe 6 to 8 hours.. but now that i've added the caustics its been running for 18 hours and is almost halfway done the second prepass. the caustic map is 216MB which seems really big.. although the causetic map didn't take that long to run. Do the caustics effect the speed of the prepasses?
(thanks a million for you help btw)

[dalomar_cg]

Re: saving prepasses / caustics

Well, they could be throwing things off. Since it sounds like you haven't seen the result yet, it would be very hard to tell. If you have only added caustics at this higher resolution I would recommend trying it at something much smaller (like 480x360) to get a feel for how they look. The caustic map is already calculated, so you don't need to recalculated it to check the result.

As to the size of the caustic map, they can get fairly big. There's a setting called Max Density that will help you reduce the total number of photons that are saved, and therefore the size of the photon map. Its kind of a finicky setting though, so it might take a few tests to really see what setting will work.