Richey Posted February 24, 2010 Share Posted February 24, 2010 Hi guys, I would like to know how to create a motion vector pass with houdini. I found two forum topics and this shader (http://www.sidefx.com/exchange/info.php?fileid=608&versionid=608) on the net they didn't work for me. Could someone please explain me how to create a motion vector shader/pass? That would be great, all the other passes work fine. Thanks a lot! Richey. Quote Link to comment Share on other sites More sharing options...
sam.h Posted February 25, 2010 Share Posted February 25, 2010 Here is an example of getting the motion vector in screen space. Note the "allow image motion blur" parm that i added to the mantra rop and turned off so that the output isn't blurred. I dunno how much you know about shading so ask if anything doesn't make sense! motionVectors.hip 1 Quote Link to comment Share on other sites More sharing options...
Richey Posted February 25, 2010 Author Share Posted February 25, 2010 Thank you so much Sam, the shader works!!! I need it for an important project. One last thing I would like to know: How can I save the shader as a vex variable - so that I can use the shader as a pass? Richey Quote Link to comment Share on other sites More sharing options...
sam.h Posted February 25, 2010 Share Posted February 25, 2010 Use a Parameter node to export the variable and set the export to 'always' Attached an example using a basic surface and exporting a pass set ... motionVectors2.hip 3 Quote Link to comment Share on other sites More sharing options...
Richey Posted February 25, 2010 Author Share Posted February 25, 2010 You are the best Sam, thank you! Quote Link to comment Share on other sites More sharing options...
Jimbo55 Posted August 16, 2012 Share Posted August 16, 2012 Hi Sam, Can you show how to use the same setup but on the geometry level? I've tried using your setup and realized that if I have anything animated on the geometry level, the vector pass doesn't work. Quote Link to comment Share on other sites More sharing options...
Jimbo55 Posted August 16, 2012 Share Posted August 16, 2012 Here is the Hip of what I am trying to attempt. motionVectors2_experiment.hipnc Quote Link to comment Share on other sites More sharing options...
sam.h Posted August 16, 2012 Share Posted August 16, 2012 You will need to have "Geo Time Samples" on at least 2 on the mantra node to get deformation blur. Let me know if that doesn't work and I will have a closer look! (You can also add Geo Time Samples to a single object if you don't want it as a global setting, add the setting to your object with the gear icon > edit rendering parameters) Quote Link to comment Share on other sites More sharing options...
Jimbo55 Posted August 16, 2012 Share Posted August 16, 2012 Sam, Thank you! Wow, so simple. That seems to have worked. Quote Link to comment Share on other sites More sharing options...
huanqing2008 Posted August 29, 2012 Share Posted August 29, 2012 thans for sharing your shader, can you please tell me how to use it in nuke for example? Quote Link to comment Share on other sites More sharing options...
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