gaurav Posted October 10, 2011 Share Posted October 10, 2011 May be I am missing out something in trail sop. To me default trail sop seems to compute velocity even if the object has come to a stop. It may be correct as a computation but visually creating motion blur artifact. If you see the file attached, Sphere stops @ frame 10 and to me should not have motion blur. Though I have got a working fix. Just out of curiosity still want to know, Is this default behavior ? How does trail sop really calculates the velocity ? Is it simply taking the derivative of current and previous positions? I haven't really plugged the numbers to check if that is the case though. Any suggestions ? Thanks, -Gaurav trailVelocity.hipnc Quote Link to comment Share on other sites More sharing options...
Emanuele Berti Posted October 10, 2011 Share Posted October 10, 2011 Is it simply taking the derivative of current and previous positions? I think so, in fact you can recreate the same result in CHOP calculating exactly that. In my scene file I just put a CHOP network and I set the derivate between the current and the next position and now at frame 10 your velocities are set to 0. Hope that helps. Cheers, Emanuele trailVelocity_CHOP.hipnc Quote Link to comment Share on other sites More sharing options...
gaurav Posted October 11, 2011 Author Share Posted October 11, 2011 I think so, in fact you can recreate the same result in CHOP calculating exactly that. In my scene file I just put a CHOP network and I set the derivate between the current and the next position and now at frame 10 your velocities are set to 0. Hope that helps. Cheers, Emanuele Thanks Emanuele for setting up it in chops and confirming. So now,Is there any way to change or force velocity computation in trail sop between current and next frame ? Same like the slope function in chops. Thanks, -Gaurav Quote Link to comment Share on other sites More sharing options...
Darric Posted October 12, 2011 Share Posted October 12, 2011 You could TimeShift by one frame, then transfer the velocities with a Point SOP. Quote Link to comment Share on other sites More sharing options...
gaurav Posted October 13, 2011 Author Share Posted October 13, 2011 (edited) You could TimeShift by one frame, then transfer the velocities with a Point SOP. Thanks for your reply. But fixing it was not the issuse. I was doing the same to avoid it if you check the hip file. My question was more about the default behaviour of velocity coumputed by trail sop this way. I thought i was missing out on something that could be related to rendering motion blur with frame centered, trailing or leading options in mantra. Cheers !! Edited October 13, 2011 by vectorblur Quote Link to comment Share on other sites More sharing options...
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