2010/4/1 Václav Šmilauer <[email protected]> > > I see in Ig2_Sphere_Sphere_ScGeom that part of the condition we create > > a ScGeom instance is: > > penetrationDepthSq>0 || c->isReal() > > Is this condition accessed only for potential interactions previously > > created? I mean, potential interactions are created because overlap > > occurs between bounding boxes, right? So has this class the power to > > create the interaction alghough no potential one exists? > > No, it doesn't have such power: the functor is called for all > interactions that exists already (both potential and real); it is the > collider that creates potential interactions for overlapping bboxes. Ig2 > functors in general can turn potential interaction into a real one (as > their purpose is exact collision detection + updating existing > geometry); they however cannot (|| c-> isReal()) erase an interaction > that already exists, even if spheres are far apart (it is Law2 that is > supposed to handle this). >
Ok, so at least a potential interaction should exists before this functor is called. BTW, do we usually enlarge the bboxes? Is that needed if I use this detectionFactor? I mean, if the bboxes perfeclty fit the spheres, and say the boxes have the same coordinates along one axis, the potential interaction is not created if we do not have a real geometrical indentation, right? cheers, Chiara > > > I need a distance of separation (that will depend on various > > parameters) between particles for the creation of the interaction. > > Should I derive a new Ig2 for sphere-sphere interaction? Now I see > > that there is a detection factor that would do something similar but I > > need something just a little more complicated. > > If you derive from the geometry functor, you will end up duplicating > fairly complicated geometrical code; I would advise against that. > > If I understand, you will have no interaction unless there is some > distance between the spheres? > Yes > > The easiest would be to set the detection factor to minimum value that > satisfies your needs (e.g. 1.5 if you need sometimes 1.2, sometimes 1.3 > and sometimes 1.5) and then, in the Law2 functor, make the decisions. If > the particles are too close, you will just exert no forces on particles. > mmh, I actually have a precise formulation that tells me how much should be this distance (depeding for instance on the equivalent radius of particles in contact and other variables). But agree that deriving a new Ig2 would lead to a duplication. > > Cheers, Vaclav > > > _______________________________________________ > Mailing list: > https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> > Post to : [email protected] > Unsubscribe : > https://launchpad.net/~yade-users<https://launchpad.net/%7Eyade-users> > More help : https://help.launchpad.net/ListHelp >
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