pradipta Posted May 31, 2008 Share Posted May 31, 2008 I am bit confuse with the number of prepass that vray calculates in the IR map generation stage. how that number of prepass gets determined in vray, can anyoe explain to me here? also why the last pass always comes black while saving the IR map for an animation? I am using 3ds max9 with vray 1.5 RC3. thanks in advance for any help... Link to comment Share on other sites More sharing options...
tayrona Posted May 31, 2008 Share Posted May 31, 2008 (edited) number of prepasses depend upon your min and max rates value (see atach), if you increase the difference between them, you got more passes and viceversa. sometimes vray makes an additional black prepass (faster), when you use materiales with hi glossies and hi subdivs.... Edited May 31, 2008 by tayrona mistake Link to comment Share on other sites More sharing options...
pradipta Posted May 31, 2008 Author Share Posted May 31, 2008 thanks Diana for your explanation, I have some hi glossi materials and that is the reason as you said for that extra black pass. Thanks again... Link to comment Share on other sites More sharing options...
kippu Posted May 31, 2008 Share Posted May 31, 2008 is it high glossy or interpolated glossiness? Link to comment Share on other sites More sharing options...
pradipta Posted May 31, 2008 Author Share Posted May 31, 2008 i guess its high glossy, not sure though! Link to comment Share on other sites More sharing options...
tayrona Posted May 31, 2008 Share Posted May 31, 2008 kippu is right...... activating "use interpolation" is the reason of aditional pass.... Link to comment Share on other sites More sharing options...
pradipta Posted May 31, 2008 Author Share Posted May 31, 2008 oh! but i dont have "use interpolation" activated in my scene. Link to comment Share on other sites More sharing options...
kippu Posted June 1, 2008 Share Posted June 1, 2008 in some old materials ..it would have been used ..and in some of them dowloaded from the vray materials site Link to comment Share on other sites More sharing options...
Dave Oliver Posted June 2, 2008 Share Posted June 2, 2008 i always thought it was from importing/xrefing/proxying/merging models that come from scenes with different lighting setups and material setups. it is really hard to go back afterwards and manage all that. so you might have some extra passes or interpolation without knowing it. Link to comment Share on other sites More sharing options...
pradipta Posted June 5, 2008 Author Share Posted June 5, 2008 yes Dave, that might be the case! Link to comment Share on other sites More sharing options...
LuckyST Posted July 27, 2008 Share Posted July 27, 2008 (edited) I've got the same question.... only thing is... I'm not using irradiance... I'm using quasi-monte carlo light cache,... and still I get 4 prepasses.... also... sometimes when I'm using irradiance, and I set min/max @ (-3/-2), I still get 4-5 prepasses. Yes, those prepasses are significantly faster, but why do I get 4/5 instead of just 2? Edited July 27, 2008 by LuckyST Link to comment Share on other sites More sharing options...
Crazy Homeless Guy Posted July 27, 2008 Share Posted July 27, 2008 When using Vray I tend to set my min prepass to somthing like -9 or -8, then my Max prepass to -2 or -1 depending on the scene. In theory, doing this should require less time to calculate the prepass, than if you leave it at -3 or -4. When Vray calculates a prepass it is adding samples to the scene, with every pass, Vray narrows down the areas that need samples, and starts skipping over the areas where it thinks no more samples are needed. Starting with -8 allows Vray to fly through the first couple of passes. While it is flying through these passes, it is already determining the areas where it is going to need to to do additional work. Then, When it gets down two your last couple of passes, it is working on these areas, and ignoring the others, where it already knows no more samples are needed. I have never done a head to head speed test to see if it truly faster, but I can tell that perceptually it does feel faster. Link to comment Share on other sites More sharing options...
tayrona Posted August 2, 2008 Share Posted August 2, 2008 (edited) I have a question about prepasses.... I am rendering an animation in HD (1920x1080), I precalculated light cache and IMAP, IMAP with medium animation preset..... Now I am rendering some test frames. Usually, I mean ALWAYS, when I precalc LC and IMAP, there are no prepasses in the rendering process, because I use the option FROM FILE in both (LC and IMAP)....... but this time, vray is making 4 prepasses before rendering the final image....... is fast but I dont understand why.... Edited August 2, 2008 by tayrona spelling Link to comment Share on other sites More sharing options...
F J Posted August 2, 2008 Share Posted August 2, 2008 I have a question about prepasses.... I am rendering an animation in HD (1920x1080), I precalculated light cache and IMAP, IMAP with medium animation preset..... Now I am rendering some test frames. Usually, I mean ALWAYS, when I precalc LC and IMAP, there are no prepasses in the rendering process, because I use the option FROM FILE in both (LC and IMAP)....... but this time, vray is making 4 prepasses after rendering the final image....... is fast but I dont understand why.... u mean before and not after, right? maybe review the config., reloading the IMAP+LC files, making sure the file path is correct.. if the prepasses still persist, maybe try reseting the scene n merging ur project into it so that u can go thru the whole config again.. Link to comment Share on other sites More sharing options...
tayrona Posted August 2, 2008 Share Posted August 2, 2008 yes I meant BEFORE Link to comment Share on other sites More sharing options...
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