Dario Arnaez Posted August 10, 2006 Share Posted August 10, 2006 Hi guys! I need you help again. From 2 or 3 days I was trying to render a big image and I don't know what I'm doing wrong... but I leave it rendering all the night and in the morning it going for the "1 or 3 pass". Jesus!!! of course I cancel it. I change some parameters and the same... here I show you some of my parameters. Ok it is really big (2560x1400) but is it logic having 2 Gb Ram??? . I don't know what is the better parameters for exterior scenes like this one. It has only one direct light. May be te DOF that I use in the render parameter are doing slow the render process but... is too much! The DOF parameters are Aperture 3 and subdiv 13. (I don't check "sides" because I haven't idea for what is that) Can anybody help me? If is necesary I can upload the Max file. Thanks!!! Link to comment Share on other sites More sharing options...
notamondayfan Posted August 10, 2006 Share Posted August 10, 2006 ur image doesnt work. try using the file upload thing here Link to comment Share on other sites More sharing options...
skogskalle Posted August 10, 2006 Share Posted August 10, 2006 you have way too high settings for your Irradience map. You have the min - max settings at -2, 0 which is great for small renders, but its too much for your 2560x1400 render. try using -4, -2 instead. i dont know how many subdivs you have for your lightcache, but for a simple exterior like this you could set it to maybe 2000 and it should still calculate fairly fast. Link to comment Share on other sites More sharing options...
Dario Arnaez Posted August 10, 2006 Author Share Posted August 10, 2006 Ohhh.... I always beliaved that for good results, the irradiance map must be up to -1, 1 or up to 0. I was wrong? Wow! It will to keep good definition? The same is for light cache. I was thinking that for to reduce the time render it must be less to 1000(the default). In this case I put on 400. Could you explain me about these wrong concepts that I have? THanks Skogskalle! Link to comment Share on other sites More sharing options...
skogskalle Posted August 11, 2006 Share Posted August 11, 2006 irradience map settings depend on the size of the render... so if your render looks good with settings -2, 0 at 640x480 you get the exact same quality with -3, -1 if you render at 1280x960, or -4, -2 at 2560x1920. The time it takes for the lightcache to calculate depends on the scene and not the size of the render (I think). So a complex interior will take lots of time even at low settings, but a simple exterior will be fast even if you use higher settings... Link to comment Share on other sites More sharing options...
dynaman Posted August 11, 2006 Share Posted August 11, 2006 wait a sec! my production renders are usually about 4800 x 3600. so you're saying that if i get a good IM result at 800x600 using -3, -1, i could go as low as -8, -6?? i find that hard to believe, but maybe i should give it a test. how much do you think it would speed up the pre-pass phase? Link to comment Share on other sites More sharing options...
bayvan Posted August 12, 2006 Share Posted August 12, 2006 You allways should check the help files becouse not all of them are useless. This is from the vray help that can be found here http://www.spot3d.com/vray/help/150R1/ Sorry for my englih Best regards' bayvan Link to comment Share on other sites More sharing options...
bayvan Posted August 12, 2006 Share Posted August 12, 2006 You allways should check the help files becouse not all of them are useless. This is from the vray help that can be found here http://www.spot3d.com/vray/help/150R1/ Sorry for my englih Best regards' bayvan Link to comment Share on other sites More sharing options...
dynaman Posted August 12, 2006 Share Posted August 12, 2006 thanks - i did read that, but it seemed a little vague. i was running some tests based on this principle, and i'd have to say at this point it seems inconclusive. on a 2400x1800 image, there is a noticeable difference using a max / min of -4 / -2 vs. -5 / -3. the -4 / -2 was slightly better on my test scene, but i do think you could get away with the lower values in a lot of cases. anyway, glad to have seen this thread as it will save me some render time in any case. Link to comment Share on other sites More sharing options...
Hoa Dinh Posted August 12, 2006 Share Posted August 12, 2006 I think it can help you something (from vray.info) irradiance min/max settings vs. image resolution posted by Wouter Wynen archived on 19.9.2003 Hi, from what I gather the irradiance map presets are resolotion dependent and optimized for 640x480...... does that mean that if I wanna double or more the render size (say 1200 or 1600 wide) will I also have to double my irradiance map settings like HSph. subdis and Interp. samples?? what about the min/max rate?? Follow-ups The irradiance min/max settings are indeed resolution dependant (the presets are just different combinations of the irradiance map settings, min/mac, clr, nrm, dist, etc...). The prepasses are calculations of irradiance map for a lower resolution of the image, and in the following prepass it uses this info to refine the solution on a bit higher resolution image etc. If the GI solution in a render looks good on let's say 800*600 with irradiance to -3,0 and you then change the res to 1600*1200, you can decrease the irradiance settings to -4,-1. (so -1 if you double resolution). This will give you almost exactly the same irradiance map. Example: If you calculate irradiance map at -3,-0 for 800*600, this means the following: prepass1: GI calculated for image with resolution 100*75 (=800/2/2/2 and 600/2/2/2) prepass2: GI calculated for image with resolution 200*150, with the info it gathered from the first pass (=800/2/2 and 600/2/2) prepass3: GI calculated for image with resolution 400*300, with the info it gathered from the second pass (=800/2 and 600/2) prepass4: GI calculated for image with resolution 800*600, with the info it gathered from the third pass Because each new pass uses the rougher info from it's previous pass, vray knows where the more important (detailed) areas are, and therefore doesn't need to calculate more samples in the less detailed (flat) areas. So if you want the same irradiance map info for the image @ 1600*1200, use -4,-1: prepass1: GI calculated for image with resolution 100*75 (=1600/2/2/2/2 and 1200/2/2/2/2) prepass2: GI calculated for image with resolution 200*150, with the info it gathered from the first pass prepass3: GI calculated for image with resolution 400*300, with the info it gathered from the second pass prepass4: GI calculated for image with resolution 800*600, with the info it gathered from the third pass HSph subdivs is the same as the hemispherical rays of fr, they only need lower values in vray. 50 is good for almost anything, try lower first, and if there are too many artifacts, go higher. Interp samples defines how the GI info at neighbouring samples is merged into each other. Higher values will tend to blur the solution, so the image looks smooth but looses detail (GI detail). Lower values will cause more splotches but better detail. So to get better quality, raise hsph and lower interp (but 50/20 is usually very good!) Another important one is clr thresh and nrm (leave dist to 0.1 always). Both 0.3 is good, lower values will cause long rendertimes. Higher values speeds up things, but you loose detail again. Link to comment Share on other sites More sharing options...
Dario Arnaez Posted August 12, 2006 Author Share Posted August 12, 2006 Thank you so much Hhoa_kts for your detailed explanation! I rendering the scene and I can see a most faster result than before. Actually, I want to thanks to all of you guys. Ok... Now ... talk about the light cache parameters for big pictures. Can I render in a small size, saving the lightcache file and then render the big one using that file? The default is 1000 but I always turn it to 500 because I thought that low is faster render. Now I'm rendering the big picture and folowing the skogskalle 's advice and put it on 2000. Even that, the render is fast! I can't believe it. Link to comment Share on other sites More sharing options...
bayvan Posted August 12, 2006 Share Posted August 12, 2006 Believe it. That's why i love vray easy to work with, very efficient and when you get the settings wright very fast renders whith the quality to match. Sorry for my English Best Regards, bayvan Link to comment Share on other sites More sharing options...
Dario Arnaez Posted August 13, 2006 Author Share Posted August 13, 2006 Yes, but I ask... when and how that number for light cache must to change? In what cases you change the default 1000 to another vault? Thanks! Don't worry about your english I don't speak it so well. Link to comment Share on other sites More sharing options...
bayvan Posted August 13, 2006 Share Posted August 13, 2006 The light cashe is resolution independent. You just have to try diferent number of subdivs and see what works for you. In my experience 1000-1500 is the maximum for allmost all of my scenes. The sample size is another parameter that affects render time. Small values gives more detail but takes longer to calculate, the image has more noise and takes a lot of RAM. The number of passes optimazes the light cashe based on how many threads your computer has. For example: single processor without hyperthreading - 1 pass two processors without hyperthreading - 2 passes two processors with hyperthreading - 4 passes Best Regards, bayvan Link to comment Share on other sites More sharing options...
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