mrWolf Posted March 27, 2015 Share Posted March 27, 2015 (edited) I have a RBD sim, with 1 packed object which contains 9 elements. I am trying to disable the gravity only on certain elements, within the packed object. In order to achieve this, I would like to control the gravity node with a dop group. I created a point attribute "falling" which I control in a sop solver, within the dop network. Then I created a DOP Group that creates a group based on the following expression: point($DOPNET+":"+$OBJID+"/Geometry",$OBJ,"falling",0) Now, this seems to work but ...not quite. I see elements that start fluctuating at a certain moment, but this moment doesn't match the moment when the "falling" attribute is triggered to 0. To start, I'd like to understand if I am using the above expression correctly. I am quite confused with the global variables $OBJID , $OBJ used with Packed Objects. Could anyone shed some light on this? I am on H13.0.547 Edited March 27, 2015 by mrWolf Quote Link to comment Share on other sites More sharing options...
pbarua Posted March 27, 2015 Share Posted March 27, 2015 Check attached file. I add falling at SOP level but you can also do it in DOPs. $OBJID isn't gonna work because rbdpacked object is just a single object. So it will be 0(depends on number of DOP objects) for all objects. dop_group_on_rbd_packed.hip Quote Link to comment Share on other sites More sharing options...
pbarua Posted March 27, 2015 Share Posted March 27, 2015 Check this thread: POP forces and Bullet sim Quote Link to comment Share on other sites More sharing options...
mrWolf Posted March 27, 2015 Author Share Posted March 27, 2015 Check this thread: POP forces and Bullet sim hi Pradeep, thank you for the example hip file, very much appreciated. Your explanation makes sense and it works great ! I was trying to stay in the rbd land and use the old style way to drive rbd objects. But I guess with rbd packed primitives , since we deal with points and transformation matrices opposed to real geometry, we are suddenly in a pop world instead ! I've read often here and there that it's possible to access the real geometry of a rbd packed primitive in a sop solver (meaning, unpack ... use and re-pack), but I wasn't able to accomplish this. Meaning that when I re-pack the element it's not the same as the one I unpacked (primintrinsic are lost when unpacking), so the sim breaks. Is there a proper way to actually extract the packed data , within DOP, use it, and repack it seamlessly ? Quote Link to comment Share on other sites More sharing options...
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