> we can display an interaction between shperes in Yade by specifying its > number with O.interactions, which gives (id1,id2). > > Now if we look for example for the normal vector or the normal force, > does it correspond (via the convention used by yade in displaying > contact ids) to the force of id1 applied on id2 or inversely ? > (same question for the normal vector)
Hi Nejib, a few things to consider: 1. If you say i=O.interactions[1,2], i is an interaction object, but its id order can be different: (i.id1==1 and i.id2==2) or (i.id1==2 and i.id2==1). 2. For the normal vector, that is always pointing from id1 to id2. If you have civil engineering background, this corresponds to the axis of the free surface on a half-beam, if you want. 3. The normal (and shear) force is oriented depending on the consitutive law, which is considered a bug (https://bugs.launchpad.net/yade/+bug/493102). I recommend that you orient normal and shear forces as applied on id1, but as other people will quickly point out, it is "just" a convention. Yes, it is "just" a convention, but it should be consistent. In most code I write (like computing stress tensor etc, where this comes to play), I assume that convention. It will take a while to unify it, but we will get there. Hope this helps, Vaclav _______________________________________________ Mailing list: https://launchpad.net/~yade-users Post to : [email protected] Unsubscribe : https://launchpad.net/~yade-users More help : https://help.launchpad.net/ListHelp
