walterbehrnes Posted January 17, 2009 Share Posted January 17, 2009 Hey guys! I have a question about writing MI files from Houdini. We are attempting to integrate Houdini into our pipeline but we have a Mental Ray farm. Is it possible to export MI files that will render on Mental Ray standalone with Houdini Shaders? When I attempt to write a MI file I get a default MR shader instead of the shader that is attached to my object. I am assuming this is because Mental Ray does not understand Mantra shaders and attaches a default MR Shader. Is it possible to pump the output of a Mantra shader into a Mental Ray shader and have this include into my MI? Any help is much appreciated! Thanks! Walter Quote Link to comment Share on other sites More sharing options...
symek Posted January 17, 2009 Share Posted January 17, 2009 Hey guys!I have a question about writing MI files from Houdini. We are attempting to integrate Houdini into our pipeline but we have a Mental Ray farm. Is it possible to export MI files that will render on Mental Ray standalone with Houdini Shaders? When I attempt to write a MI file I get a default MR shader instead of the shader that is attached to my object. I am assuming this is because Mental Ray does not understand Mantra shaders and attaches a default MR Shader. Is it possible to pump the output of a Mantra shader into a Mental Ray shader and have this include into my MI? Any help is much appreciated! Thanks! Walter Hmm, Houdini comes with mental ray specific shaders, and those have to applied to render with mental ray... is this is what you tried? Quote Link to comment Share on other sites More sharing options...
pbd Posted January 18, 2009 Share Posted January 18, 2009 Hey guys!I have a question about writing MI files from Houdini. We are attempting to integrate Houdini into our pipeline but we have a Mental Ray farm. Sorry to hear that Is it possible to export MI files that will render on Mental Ray standalone with Houdini Shaders? No. The only shaders that will work with mr are the mental ray one (goto shop, hit tab, anything in the mentalray sections). When I attempt to writea MI file I get a default MR shader instead of the shader that is attached to my object. I am assuming this is because Mental Ray does not understand Mantra shaders and attaches a default MR Shader. Is it possible to pump the output of a Mantra shader into a Mental Ray shader and have this include into my MI? No, mainly because mental ray does not have a shading language (their attempt to copy and extend rsl called "metasl" is not production-ready and has no VM compiler, nor via C++ compile you can get stable shaders as of today). You need to rewrite them by hand in C++ via the mental ray API (we could help you in this, but do you really need to? ). Just use VEX with Mantra or RSL shaders with a RenderMan renderer, once you see their strengths it you will ditch mental ray without remorse. P. Quote Link to comment Share on other sites More sharing options...
walterbehrnes Posted January 19, 2009 Author Share Posted January 19, 2009 Thanks guys! That is what I thought regarding Mental Ray, I think we are going to try and get Mantra working. I agree, I like Vex and Mantra much more than Mental Ray. I will get back with you if I have any questions on setting up our farm to handle this. Thanks! Walt Quote Link to comment Share on other sites More sharing options...
Jason Posted January 19, 2009 Share Posted January 19, 2009 Thanks guys! That is what I thought regarding Mental Ray, I think we are going to try and get Mantra working. I agree, I like Vex and Mantra much more than Mental Ray. I will get back with you if I have any questions on setting up our farm to handle this. Thanks! Walt I don't think you'll regret getting Mantra working -it's just getting better and better:) If you have any questions on it, we'd be happy to help out. Quote Link to comment Share on other sites More sharing options...
walterbehrnes Posted January 20, 2009 Author Share Posted January 20, 2009 I don't think you'll regret getting Mantra working -it's just getting better and better:) If you have any questions on it, we'd be happy to help out. Thanks! we got it running on the farm now. Very exciting! I do have a related question. Yesterday I was attempting to bring maya's camera into houdini using the fault camera otl, but no matter what I did I could not get the camera to match up. The position of the camera was fine but the images were off when it came to the lens parameter. I was finally able to get the camera to match using an fbx file. Really thought I need to be able to build a custom camera and update the camera from a chan file. So, my question is. What is the math behind the camera conversion from maya to houdini? which parameters need a conversion? Also, is this documented anywhere? Thanks! Walter Quote Link to comment Share on other sites More sharing options...
SpencerL Posted January 20, 2009 Share Posted January 20, 2009 Thanks! we got it running on the farm now. Very exciting!I do have a related question. Yesterday I was attempting to bring maya's camera into houdini using the fault camera otl, but no matter what I did I could not get the camera to match up. The position of the camera was fine but the images were off when it came to the lens parameter. I was finally able to get the camera to match using an fbx file. Really thought I need to be able to build a custom camera and update the camera from a chan file. So, my question is. What is the math behind the camera conversion from maya to houdini? which parameters need a conversion? Also, is this documented anywhere? Thanks! Walter Maya Aperture is in inches where as Houdini's is in millimeters. Houdini Aperture = Maya Horizontal Aperture * 25.4 Vertical ap = horizontal/aspect e.g. /1.777777 for HD Quote Link to comment Share on other sites More sharing options...
walterbehrnes Posted January 20, 2009 Author Share Posted January 20, 2009 Maya Aperture is in inches where as Houdini's is in millimeters.Houdini Aperture = Maya Horizontal Aperture * 25.4 Vertical ap = horizontal/aspect e.g. /1.777777 for HD Ah! that worked great! That was simple! Thanks! Quote Link to comment Share on other sites More sharing options...
Jason Posted January 21, 2009 Share Posted January 21, 2009 Ah! that worked great! That was simple! Thanks! One day, someone with extreme patience and a lot of time will attempt to set up all the same parms and features of a Maya camera in Houdini. Boy does that camera have a lot of setttings! Certainly doesn't abide by the KISS principle of design. Quote Link to comment Share on other sites More sharing options...
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