taming mental ray (English version)

So far, I told about exporting an mi file. Now here is the shader conversion for iray. iray supports mia_material. To reuse current scenes, it is nice if I could convert the 3dsmax shaders to mia_material (Arch&Design) shader. I could imagine that some of other shaders will be supported also, but, iray is a CUDA program. CUDA has a divergence problem, it means, if many kind of shaders are in the scene, the performance becomes low. That's natural. A shader is a function and many different shaders are running on a CUDA device, I could see it will be slow. But, if the same function everywhere, then CUDA works well. (in theory. If function itself has a lot of branches, then there is a problem. Though many obstacles are there, but many kind of shaders seems to have not so chance. ) Also I imagine there is less trouble if I use the mental images native supported shaders since iray is a new renderer. In my personal opinion, I would convert the shaders. You can find 3dsmax shaders

As an example in here, I create one teapot in 3dsmax and assign a mia_material (Arch&Design). Since 3dsmax exports an mi file with 3dsmax shader dependency, mental ray standalone could have a problem to render that mi file. mental ray standalone usually doesn't have 3dsmax shaders. The main advantage of the standalone mental ray is parallel rendering on a render farm. I couldn't tell the legal license of the 3dsmax shaders. For the safe side, if we have no dependency to the 3dsmax shaders, it shouldn't have a problem. (Or you can also install 3dsmax to all the render farm machine, though it doesn't make much sense.) If I just render the mi file from the 3dsmax without modifying, I see the following error. --- > ray -x on -v 5 00teapot_ex00.mi ... LINK 0.0  error  191007: cannot load 3dsmaxhair.dll, The specified module could not be found. ... LINK 0.0  error  191007: cannot load mayabase.dll, The specified module could not be found. ... LINK 0.0  err

How to export mi file from 3dsmax. 1. Assign mental ray renderer as Production renderer First open the Render Set Up dialog. Figure export_mi_1 show that opening the rollout of assign renderer and then choosing the mental ray renderer as Production renderer. Figure export_mi_1 2. Export a mi file from 3dmax. Choose Render Set Up --- Processing Tab. First you need to choose a filename as in Figure export_mi_2. Without a file name, the checkbox of 'Export on Render' is disabled. This was difficult for me. I wanted to export a file, but Export on Render is disabled. I wish I could choose the Export on Render and then see a warning message, ''an export file name is not specified.'' Next, push the Render button, then a mi file is exported. Figure export_mi_2 This is also difficult for me. When you ' export ' a file, push the ' render ' button. I wish it was like   When you ' export ' a file, push the ' export '

Even iray has no customized shaders, iray has a shader. It is mia_material (Arch&Design in 3dsmax) only. Actually, it is a shader that has mia_material interface and the implementation is different from mental ray (only for iray). mental images explains this is for the users who already know the mia_material. Such user doesn't need to learn the iray shader from the scratch. Therefore, some of the physically meaningless parameters of mia_material are disabled. They also said that they will support more physical shaders, like BRDF shaders. Someone  asked about volume shaders support at the confenence, but, unfortunately, iray version 1 doesn't support volume shaders and will be supported in the following versions sometime. As for a DCC software user, the problem of iray is they can use it from 3dsmax/Maya/XSI or not. But NVidia's explanation is 'that is autodesk's decision.' Although, mental ray 3.8+ standalone or NVidia RealityServer support iray. (See ment

* As far as I know, we can only run mental images' iray in NVidia's RealityServer. I hope Autodesk 3dsmax/maya/xsi supports iray soon. mental images (a subsidiary company of NVidia) demonstrated iray renderer in GDC's keynote and SIGGRAPH ASIA 2009. GDC NVidia iray demo (YouTube) mental images iray page mental ray or some other renderers can simulate indirect illumination in some extent, but the methods final gather or photon map are quite rough approximation. They have no guarantee to converge to the correct answer. Also there are many renderer parameters for performance optimisation. These parameters heavily depends on the scene. It is difficult to achieve high quality and faster rendering. These methods are anyway time consuming, therefore, we sometimes put invisible light sources by hand, that simulates indirect lights. This iray is a brute force path tracer and there is no renderer parameter, but nowadays computer has not enough power to compute the light tran

There was a critical license related bug in mental ray 3.7 on Intel Core i7 and the fixed version seems to be distributed now. http://forum.mentalimages.com/showthread.php?t=5511 The fixed mental ray (SPM) version (might depends on OEM) is the following. mental ray 3.7: 3.7.1.31 (2009 September 16) or higher mental ray 3.7+: 3.7.53.6 (2009 October 22) or higher The detail of this problem is: When you want to run mental ray on Intel Core i7 machine, you will get the following error message: Sorry, no license available and can not run mental ray even you have enough licenses left. It seems recent Intel's CPU becomes complex to count the number of cores. This bug seems related with this. http://software.intel.com/en-us/articles/intel-64-architecture-processor-topology-enumeration/ Personally, I don't like the license that limits the number of cores. Because the new machines has more cores, but we can not use these cores because of license shortage. If I buy a new machine