sibarrick Posted April 19, 2007 Share Posted April 19, 2007 (edited) Forgive me if this is common knowledge it was news to me and as far as I can tell I can't find this mentioned in the help but it should be. Maybe its obvious when you think about it but turning on the irradiance cache in a rop will speed up renders that use the occlusion vop - at least if you use it in a light, i haven't tested it for anything else, but i'd put money on it would. Here's a test scene no gi lights just normal ones with a special occlusion light shader - in other tests I have seen a 3-4 times speed up for brute force occlusion rendering. You have to play with the parameters to get good quality without loosing the speed enchancement but depending on the situations you use occlusion in this in it is a useful thing to know at least. I guess if you actually write the cache to disk you get even more speed increase but I haven't had time to test that yet. occlusionlight1.hipnc Edited April 19, 2007 by sibarrick Quote Link to comment Share on other sites More sharing options...
MADjestic Posted April 19, 2007 Share Posted April 19, 2007 Forgive me if this is common knowledge it was news to me and as far as I can tell I can't find this mentioned in the help but it should be.Maybe its obvious when you think about it but turning on the irradiance cache in a rop will speed up renders that use the occlusion vop - at least if you use it in a light, i haven't tested it for anything else, but i'd put money on it would. Here's a test scene no gi lights just normal ones with a special occlusion light shader - in other tests I have seen a 3-4 times speed up for brute force occlusion rendering. You have to play with the parameters to get good quality without loosing the speed enchancement but depending on the situations you use occlusion in this in it is a useful thing to know at least. I guess if you actually write the cache to disk you get even more speed increase but I haven't had time to test that yet. occlusionlight1.hipnc A nice find, Sibarrick! Looks like days of omni consumer Fast Gi are really almost there =) I did a couple of test. I've got some other processes running on my box and so I've got around 40% of CPU time free for Houdini. So with these 40% free, I got: ~1min56sec for a default 320x243, non cached light image ~10-12sec per a same image, with lighting cached to disk. Oh yeah, feel the difference! I bet the difference will be increasingly drastic when dealing with bigger images. Quote Link to comment Share on other sites More sharing options...
edward Posted April 19, 2007 Share Posted April 19, 2007 Note that in prman, there's no way to turn OFF irradiance caching. Quote Link to comment Share on other sites More sharing options...
Jason Posted April 20, 2007 Share Posted April 20, 2007 Note that in prman, there's no way to turn OFF irradiance caching. Thats one thing about prMan which they generally are quite clever about: forcing people to use optimized stuff. That and the way they force users to use .tex format files, thereby keeping antialiasing good due to mipmapping and RAM usage down due to paging. I was always proud that Houdini/Mantra handled all image formats but after working with lighters that insist on sabotaging their own renders with huge non-paged textures, I think it was kinda genius.() I know that Mantra warns that memory and antialiasing will be affected with non-.rat textures but it's amazing how blind you get to messages. Hey Simon, Irradiance caching is a great thing when used right, thats for sure. Although - a warning - it is possible to achieve slowdowns if your Error is set too low, it should be tweakable to the point that it should speed up your renders and reduce the noise. So it can benefit quality and speed quite significantly. If you write out caches to disk (by specifying a disk file) and then re-render in Read mode, your renders will be quickest and the most reliably sampled. This is because it can really truly know how to reconstitute a value from the samples in the cache. Quite obvious when you think about it, but I thought I'd point it out. I have this feeling that irradiance caching will only get better and play a larger role in Mantra in upcoming versions. Quote Link to comment Share on other sites More sharing options...
sibarrick Posted April 20, 2007 Author Share Posted April 20, 2007 Irradiance caching is a great thing when used right, thats for sure. Although - a warning - it is possible to achieve slowdowns if your Error is set too low, it should be tweakable to the point that it should speed up your renders and reduce the noise. So it can benefit quality and speed quite significantly. That's why I mentioned having to play with the parameters to get a good balance between quality and speed. Definitely seeing great speed increases. Once again Sesi miss a trick by not making this more obvious in the help. It took several emails to Andrew (for those that don't know he's a developer working on Mantra) before I found out that this would work.... Seems a lot of people do know about it but I'm guessing only through PRman, which is crazy.... I'm still not sure its even in the help, does anyone know where it is mentioned? If you write out caches to disk (by specifying a disk file) and then re-render in Read mode, your renders will be quickest and the most reliably sampled. This is because it can really truly know how to reconstitute a value from the samples in the cache. Quite obvious when you think about it, but I thought I'd point it out. Oh, yes I did do some test with this in the end, very much quicker still. Unfortunately, as usual, completely inpractical for the situation I'm in, but nice to know. Good for most users I suspect. I have this feeling that irradiance caching will only get better and play a larger role in Mantra in upcoming versions. Cool, waiting for H9 to beta is getting painful...... I can't wait any longer. I know its going to be worth it though. Quote Link to comment Share on other sites More sharing options...
MADjestic Posted April 20, 2007 Share Posted April 20, 2007 I'm still not sure its even in the help, does anyone know where it is mentioned? hdox://houdini/content/base/tutorials/fm_09_guide_lighting_1013748.html this help page deals with irradiance caching, but the discussed setup has GI lights, so it is not exactly the case, described in your scene. Whether it is mentioned somewhere that the light caching technique can be generalized to non-GI lights, - I am not sure about that. Maybe after H9 is out, SESI might consider creating a manual of some sort on Mantra, similar to Advanced Renderman? - I am sure that would be of much usage to most TDs out there, as well as anyone willing to explore the world of Mantra. For now everyone seems to have to study Mantra trough Renderman. Not bad, but isn't that situation weird, if you think about it? Quote Link to comment Share on other sites More sharing options...
sibarrick Posted April 21, 2007 Author Share Posted April 21, 2007 Oh yeah I found that page, that was what threw me off course. I read all those notes and tried all those techniques and that wasn't working very well for me, so I went back to doing brute force occlusion tests. Then lucky I was using a hip file that I had previously set up for gi and had accidently left the irradiance cache on, suddenly I had quick renders, that had me scratching my head for a while til I found out that it was the cache doing its job. Went back to the help but no mention of it for the occlusion vop or anywhere else. It was pure luck really. Actually now I think about no-one at Sesi actually said try occlusion and irradiance caching together, Andrew did say try irradiance caching, but at the time I assumed he meant with gi lighting. But I guess it was what he meant. Anyhoo it needs to be explicitly in the docs. Probably in the irradiance caching section, and the help for rops and the occlusion vop. It makes me wonder if there are any other gems out there like this that make renders go faster? My other big tip is using the camera crop settings. That makes a huge difference to big frames, or ones with lots of geometry. We actually render ifds and have python chop them up into 12 or so pieces and render all the bits seperately, its way quicker than trying to do the whole frame in one hit. Quote Link to comment Share on other sites More sharing options...
LaidlawFX Posted November 4, 2009 Share Posted November 4, 2009 Hello, The irradiance tab in the mantra rop works great especially for speedy occlusion and all, but does any one know the file format to write out the irradiance cache in? All the documentation on it just doesn't say what type of file it is? I can write it out to a nice big file... but after that I am kind of running out of info on what I just created. It certainly not an asci file either I certainly owe some one a beer for this one, other wise I need to write this one off. Quote Link to comment Share on other sites More sharing options...
rob Posted November 4, 2009 Share Posted November 4, 2009 Hi, Write the file out as .pc for pointcloud rob Quote Link to comment Share on other sites More sharing options...
LaidlawFX Posted November 7, 2009 Share Posted November 7, 2009 (edited) Hi, Write the file out as .pc for pointcloud rob Woot! I owe you a beer. ...ok now I'm wondering now since I'm con-currently learning prman at the the same time is there a way to view the point cloud in houdini, like ptviewer for prman? I know you can easily view photon maps with the file node, like mental rays photon display for Maya. Just knowing it is a point cloud and not some other concept has opened a whole bunch of other documentation that I need to look into now and put the puzzle pieces together with. It would be nice if they had a thick book on these advanced concepts for render engines. Edited November 7, 2009 by LaidlawFX Quote Link to comment Share on other sites More sharing options...
symek Posted November 7, 2009 Share Posted November 7, 2009 is there a way to view the point cloud in houdini, like ptviewer for prman? I know you can easily view photon maps with the file node... the same way you can open point cloud data, with a file SOP in sops. No special treatment here. Houdini silently converts geometry it knows for bgeo format to display it, photons, pc, obj etc. Woot! I owe you a beer. me too? cheers, skk. Quote Link to comment Share on other sites More sharing options...
LaidlawFX Posted November 8, 2009 Share Posted November 8, 2009 (edited) yeah, you too... but if you ain't in San Francisco, or live in the north east of the US it may take a while... ?airmail? lol (Grad School) = Loans = ((No Travel * 10yrs) - (Job(Quality of Job) * X yrs) Edited November 8, 2009 by LaidlawFX Quote Link to comment Share on other sites More sharing options...
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