thinkinmonkey Posted February 1, 2012 Share Posted February 1, 2012 Hello all, just a simple question: how can I pass an angvel or rotation attribute to an RBD simulation like I do with velocity(v) at SOP level? In the scene a simple cube is acting like a cannonball: in the SOP network I assigned it an attribute for velocity (v) <6, 8, 0> and checked the "Inherit Velocity from Point Velocity" parameter in RBD Object. I'd like the cube spins when in the air, but assigning an angvel attribute doesn't seem to work. Thanks in advance. P.S. Well, yes! After a search, I discovered to use "v" instead of "vel" or "velocity" in order to have a working simulation, so I'd like to know if there's a table where every variables in Houdini is described. applyingAngVel.hipnc Quote Link to comment Share on other sites More sharing options...
rafaelfs Posted February 1, 2012 Share Posted February 1, 2012 looks like a bug to me, rather than something you did wrong... What version and build are you using? Cheers Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted February 1, 2012 Author Share Posted February 1, 2012 Hi rafaelfs, I'm using Houdini 11.1.118. Why is it a bug for you? Did you find a different version/build of Houdini where the "angvel" attribute works as I wish? If so, please tell me which one. Quote Link to comment Share on other sites More sharing options...
gaurav Posted February 1, 2012 Share Posted February 1, 2012 Hi, Point velocity (v) itself is used to calculate the resulting angular velocity. It works as expected. Not a bug. See the attached file. Cheers, applyingAngVel01.hipnc 1 Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted February 1, 2012 Author Share Posted February 1, 2012 Hi vectoblur, that's all?!?! Just throw random/different v per points? Hmmm... interesting! Thanks a lot. Quote Link to comment Share on other sites More sharing options...
rafaelfs Posted February 1, 2012 Share Posted February 1, 2012 Point velocity (v) itself is used to calculate the resulting angular velocity. It works as expected. Not a bug. See the attached file. Cheers, I see your point, so if one wants to control angular velocity in SOP level they'll have to adjust the velocity vector to match a desired spin... Quote Link to comment Share on other sites More sharing options...
rafaelfs Posted February 1, 2012 Share Posted February 1, 2012 Hi rafaelfs, I'm using Houdini 11.1.118. Why is it a bug for you? Did you find a different version/build of Houdini where the "angvel" attribute works as I wish? If so, please tell me which one. Not that I found a version where it works, but that I tend to think that if you're feeding angular velocity the RBD sim should pick it up, rather than override it. But I see the point of the current state of things, basically that attribute was designed for a pipeline where houdini would take point velocities baked in a geometry that came from another software, instead of getting it from point attributes created in SOP. I guess that if you want Houdini to pick it up then you'd have to create the appropriate expressions in the angular velocity parameters of the RBD object to pick up the SOP attributes. cheers Quote Link to comment Share on other sites More sharing options...
gaurav Posted February 1, 2012 Share Posted February 1, 2012 that's all?!?! Yeh.. Apparently. I guess its easy to mix experiences of other contexts in dops. For example angular velocity (w) in pops is given by the axis and a rate of change in rotation over time + axis itself could be defined in 2 different forms. But with rbd state data its little straight forward. Cheers, Quote Link to comment Share on other sites More sharing options...
rafaelfs Posted February 2, 2012 Share Posted February 2, 2012 I was fiddling with a quick setup to get some angular velocity from SOP. It's rough, but I can see it being streamlined into an asset... Have fun!!! applyingAngVel.hipnc Quote Link to comment Share on other sites More sharing options...
thinkinmonkey Posted February 2, 2012 Author Share Posted February 2, 2012 Hi Rafaelfs, you get a nice, artist-drivable solution: you can transform the circles to have different effects. Interesting this way too! Quote Link to comment Share on other sites More sharing options...
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