Scratch Posted March 20, 2012 Share Posted March 20, 2012 (edited) Hey all! I'm taking houdini classes over at vfxlearning.com and last week we got an introduction to mantra. I wanted to take a closer look at all those rendering concepts and while doing so, I came across some questions which I hope you folks can help to clarify. Here we go: Mantra Comands or command line options: We were told that mantra renders faster when you do not use the checkbox "use all processors". Instead we set this function using a mantra commannd. Furhtermore, our mentor told us that you have to set the (RAM) memory limit mantra uses manually to a high value, and that it will speed up the render drastically. Here is what we typed in mantras main tab -> command: mantra -j 0 -M 16000 What I found in the help (http://www.sidefx.com/docs/houdini12.0/rendering/commandline) -M memory: Set the renderer:geocachesize property. -j numthreads: Specify the number of threads (-j 0 uses maximum threads). Qestions here: * Is this don't use "use all processors" checkbox and type it in as command - thing still valid? * Is cache memory ration on the properties tab -> subtab render identical with the command -M 16000? (here setting the memory limit (RAM) for Mantra to 16GB, which is my built in total RAM value) * Can you set thouse things we set using code also using a menue or a checkbox? Next thing: Verbos Statistics I can't get houdini/mantra to display verbos information. I've set the verbos level to something higher than 0 (mantra settings), but there is no additional window or anything popping up which displays this information. I'm sure I'm just missing something minor here. How can I activate verbos statisics properly? Last topic I want to talk about: PBR vs. Micropolygon -> what are the differences? I know micropolygon works with micropolygons, dicing and all this (like Renderman), and PBR uses raytracing methods. I furthermore know that micropolygon is very fast when it comes to motionblur, DOF and displacement - calculations and that the micropolygon engine can be hybrid, calling for raytracing functions if needed automatically (e.g reflections etc.) I watched a tutorial from Peter Quint about PBR, and since Houdini 12 is out, everything he said about what is unique for PBR and what standard micropolygon rendering can't do seems now possible. The only difference I can find, the only thing you can't do (as far as I know) is that when it comes to GI, you can't do multiple diffuse bounces using the micropolygon render engine. (I'm not refering to micropolygon PBR here, I'm comparing PBR with standard micropolygon rendering (mantra default render engine)). Question here: Can you help me defining some other differences between PBR and Micropolygon rendering? Has this been discussed somewhere here before? I dont want to warm up old stuff, i did a quick search but couldn't find anything particular to this topic. I'm looking forward to your answers and want to say thx for your help in advance! Overall I have to say that I start to like mantra, eventhough it is a bit confusing at the start. But if you are familiar with rendering concepts in general (I use e.g. Vray alot at work) and you start watching Peter's tutorials, you pertty fast get the idea how stuff works in houdini! Greets from Austria Philipp Edited March 20, 2012 by Scratch Quote Link to comment Share on other sites More sharing options...
Scratch Posted March 21, 2012 Author Share Posted March 21, 2012 Noone here who can help me on this stuff? Quote Link to comment Share on other sites More sharing options...
Erik_JE Posted March 21, 2012 Share Posted March 21, 2012 (edited) Nice wall of text there The Use all processors usually work fine (does for me) but I know that some people have had to enforce it. There is no need to use a command like that for it tho. It's all available in the options. Geometry cache is default to 256. On a modern computer with lots of ram 1024 or more is probably a good choice so the instructor was correct there but it can also be used without commands. I don't know what operating system you are using but if you use linux and start houdini from the terminal the verbose statistics will be outputted to the terminal. Last question I am too lazy to answer as a big book could be written about it and have been. Edited March 21, 2012 by Erik_JE Quote Link to comment Share on other sites More sharing options...
Scratch Posted March 21, 2012 Author Share Posted March 21, 2012 Sorry for the long text but starting 3 different threads for each question would be silly either I guess First of all, thx for digging through it! I'm using a Windows Machine with 16GB of RAM, so should I type in -M 16000 then? Or is less sufficiant? Has that anything to do with cache memory ratio? Hmm..maybe I then have to start houdini from the command-line too in Windows to get Verbose information, I'll give that a try! You helped already a lot, so no worries about the render engine questions. Thanks! I'll keep digging Quote Link to comment Share on other sites More sharing options...
symek Posted March 22, 2012 Share Posted March 22, 2012 You don't have to use command-line options. They simply overwrites values specified by MantraROP in case someone wants to change them after ifd files were written to disk. -M flag used to controlled geometry cache, which prior to H12, was separated from texture cache. Currently they're unified and controlled by vm_cachesize or vm_cacheratio properties (via corresponding parameters). There is no reason to set this cache too high. It won't help in normal cases. Unified cache is just a part of memory used by Mantra anyway. You can always perform test on your scene to verify it. As to a differences between PBR and REYES, you seem to be grasping it well. Introduction to Mantra form Help describes it very well. What else you want to know? Quote Link to comment Share on other sites More sharing options...
Scratch Posted March 22, 2012 Author Share Posted March 22, 2012 Wow cool! Thx for that indepth explaination, that brings some light to all this! CACHE RATIO So given that I have 16GB of Ram, what cache ratio should I set? I assumed, the more memory mantra has, the better it is right? (since constant unloading and loading of things due to too less RAM space makes it slow I'd assume - compared to one big place where it can constantly load/extend memory, not running into a limit. Is that true? This is what I found in the manual (thx for the hint!) Cache ratio The proportion of physical memory Mantra will use for its unified cache. For example, with the default vm_cacheratio of 0.25 and 16 Gb of physical memory, Mantra will use 4 Gb for its unified cache. The unified cache stores dynamic, unloadable data used by the render including the following: 2D .rat texture tiles 3D .i3d texture tiles 3D .pc point cloud pages (when not preloaded into memory) Tessellated meshes required by ray tracing Displacements Subdivision surfaces Bezier and NURBS primitives VERBOSE STATISTICS In order to be able to perform rendertests myself, I somehow need to see the exact rendertime. So how can I activate/see verbose statistics on Windows?. I switched it on (setting a value greater than 0 in the mantra node), but nothing happens. Quote Link to comment Share on other sites More sharing options...
spev Posted March 22, 2012 Share Posted March 22, 2012 To turn on the console in win go to the mantra rop and in the main tab form the mantra command type mantra -o consolewait If you select the little triangle drop down to the right of the text box you can chose an option that says `verbose to console windows only`...I have found that you need to set a verbosity level in properties->statistics->verbose level This use to work very reliably in h11 but on my system (win7 64) h12 seems a bit random as to whether the console decides to pop up or not... I hope this helps Spev Quote Link to comment Share on other sites More sharing options...
eetu Posted March 22, 2012 Share Posted March 22, 2012 VERBOSE STATISTICS In order to be able to perform rendertests myself, I somehow need to see the exact rendertime. So how can I activate/see verbose statistics on Windows?. I switched it on (setting a value greater than 0 in the mantra node), but nothing happens. By default the verbose info goes into the ROP node info, which you can see by middle mousing the ROP. Kinda awkward for long info though. Quote Link to comment Share on other sites More sharing options...
Scratch Posted March 22, 2012 Author Share Posted March 22, 2012 To turn on the console in win go to the mantra rop and in the main tab form the mantra command type mantra -o consolewait If you select the little triangle drop down to the right of the text box you can chose an option that says `verbose to console windows only`...I have found that you need to set a verbosity level in properties->statistics->verbose level This use to work very reliably in h11 but on my system (win7 64) h12 seems a bit random as to whether the console decides to pop up or not... I hope this helps Spev Thx for taking the time to help me here! I tried all this, but it seems that it decided not to pop up on my system too (using Win7, 64Bit, Apprentice License) Hmm...i guess it is a general bug here. Middle Mousing the ROP works, and I think this has to do it until the console is fixed. Thx! Quote Link to comment Share on other sites More sharing options...
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