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[Jan Stránský <question313648@xxxxxxxxxxxxxxxxxxxxx>]

Question #313648 on Yade changed:
https://answers.launchpad.net/yade/+question/313648

    Status: Open => Answered

Jan Stránský proposed the following answer:
Hi Jean-François,
as a reference for other users who might have the same problem, could you
please write how did yo solve it or what was misinterpreted?
Thanks
Jan


2016-08-04 12:27 GMT+02:00 Jeff <question313648@xxxxxxxxxxxxxxxxxxxxx>:

> Question #313648 on Yade changed:
> https://answers.launchpad.net/yade/+question/313648
>
>     Status: Answered => Open
>
> Jeff is still having a problem:
> Hi Jan
> Sorry for the late answer  but I was away from my desk
>
> I explored my problem a bit further and I am happy to report that there is
> no trace of bug iassociated to my problem
> just a poor use of the code by a beginner
> All is  just working fine now !
>
> thanks for your patience and willingness to answer though even if the
> question was naive
>
> JF
>
>
> Jean-François Leon
> Galtenco
>
> Tel [Main-Global]: +1 (415) 322-0376
> Cell [France]: +33 (651) 168-014
>
> On Mon, Aug 1, 2016 at 6:17 PM, Jan Stránský <
> question313648@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> > Your question #313648 on Yade changed:
> > https://answers.launchpad.net/yade/+question/313648
> >
> >     Status: Open => Answered
> >
> > Jan Stránský proposed the following answer:
> > Hi Jean-François,
> >
> > In fact I initially tried the difference between 2 cylinders you suggest
> > and
> > > I then moved to the revolution surface because I found that the
> > > inside cylinder was fully filled as soon as its diameter  was close to
> > the
> > > sphere diameter.
> >
> >
> > I am not sure if I got it, could you please send a cript reproducing this
> > problem? There might be some bug in the code..
> >
> > I thought that the revolution surface approach I posted will give me
> > an explicit
> > > control of the angular discretization. I found with a few experiment
> that
> > > it was indeed playing a role on the performance of the algorithm but I
> > > could never come close to the wire I need to model... so my post.
> >
> >
> > The problem with inGtsSurface is that it evaluates the sphere
> in/ousideness
> > only approximately in 6 axis aligned directions [1]. It should not be
> > difficult to make it more exact.
> >
> > I assume when you mention other aproach that you are suggesting gravity
> > filling
> > > with sphere factory ?  something else?
> >
> >
> > gravity deposition is one option, some kind of compression within desired
> > volume is another similar option.
> >
> > Random dense pack first create a packing an then it is "cropped" to the
> > geometry, so near boundary the packing is not optimal. You can also use
> > randomDensePack(...,cropLayers=3), from certain point of view it improves
> > the results [2,3]. Using this parameter and difference of two cylinders,
> I
> > got (from my point of view :-) OK results.
> >
> > cheers
> > Jan
> >
> > [1]
> >
> >
> https://yade-dem.org/doc/yade.pack.html#yade._packPredicates.inGtsSurface.__init__
> > [2] https://answers.launchpad.net/yade/+question/291326
> > [3] https://yade-dem.org/doc/yade.pack.html#yade.pack.randomDensePack
> >
> >
> > 2016-08-01 23:42 GMT+02:00 Jeff <question313648@xxxxxxxxxxxxxxxxxxxxx>:
> >
> > > Question #313648 on Yade changed:
> > > https://answers.launchpad.net/yade/+question/313648
> > >
> > >     Status: Answered => Open
> > >
> > > Jeff is still having a problem:
> > > Hi Jan,
> > > Thank you for your answer.
> > >
> > > in fact I initially tried the difference between 2 cylinders you
> suggest
> > > and I then moved to the revolution surface because I found that the
> > inside
> > > cylinder was fully filled as soon as its diameter  was close to the
> > sphere
> > > diameter.
> > >  I thought that the revolution surface approach I posted will give me
> an
> > > explicit control of the angular discretization. I found with a few
> > > experiment that it was indeed playing a role on the performance of the
> > > algorithm but I could never come close to the wire I need to model...
> so
> > my
> > > post.
> > >
> > > I assume when you mention other aproach that you are suggesting gravity
> > > filling with sphere factory ?  something else?
> > >
> > > Thanks anyway
> > > JF
> > >
> > > Jean-François Leon
> > > Galtenco
> > >
> > > Tel [Main-Global]: +1 (415) 322-0376
> > > Cell [France]: +33 (651) 168-014
> > >
> > > On Mon, Aug 1, 2016 at 9:12 AM, Jan Stránský <
> > > question313648@xxxxxxxxxxxxxxxxxxxxx> wrote:
> > >
> > > > Question #313648 on Yade changed:
> > > > https://answers.launchpad.net/yade/+question/313648
> > > >
> > > >     Status: Open => Answered
> > > >
> > > > Jan Stránský proposed the following answer:
> > > > Hi Jeff,
> > > >
> > > > I am new to Yade
> > > >
> > > >
> > > > welcome :-)
> > > >
> > > > You can define the predicate as a difference of two cylinders [1]. If
> > the
> > > > gap between inner wire and inner particles is too big, then you would
> > > have
> > > > to use different initial packing method than random dense pack.
> > > >
> > > > ####################
> > > > pred = pack.inCylinder((0,0,0),(0,0,length),rOut) -
> > > > pack.inCylinder((0,0,0),(0,0,length),rIn)
> > > > sp=pack.randomDensePack(pred,radius=rS,returnSpherePack=True)
> > > > sp.toSimulation()
> > > > ####################
> > > >
> > > > cheers
> > > > Jan
> > > >
> > > > [1]
> > https://yade-dem.org/doc/user.html#boolean-operations-on-predicates
> > > >
> > > >
> > > > 2016-08-01 14:13 GMT+02:00 Jeff <
> question313648@xxxxxxxxxxxxxxxxxxxxx
> > >:
> > > >
> > > > > New question #313648 on Yade:
> > > > > https://answers.launchpad.net/yade/+question/313648
> > > > >
> > > > > Hi All
> > > > >
> > > > > I am new to Yade and this is my first post.
> > > > >
> > > > > I am trying to generate a random dense packing in  a cylinder
> with  a
> > > > fine
> > > > > wire on its axis:
> > > > > my problem : the wire size being much smaller than the sphere
> > diameter,
> > > > > the spheres overlap it completely and make it "useless as such"
> > > > > Can someone could provide some advice for improving this
> packing...?
> > (
> > > I
> > > > > would like the sphere against the wire not inside..)
> > > > > Thanks a lot
> > > > >
> > > > > JF
> > > > >
> > > > > the instructions I use are pretty simple ( copied and slightly
> > adapted
> > > > > from some example):
> > > > >
> > > > > ###geometry definition
> > > > > rIn=0.75 # wire radius
> > > > > rOut=13 #cylinder radius
> > > > > length=320 # cylinder length
> > > > > rS=2.6 #sphere radius
> > > > >
> > > > > poly=((rIn,length),(rOut,length),(rOut,0),(rIn,0),(rIn,length))
> > > > > thetas=arange(0,2*pi,pi/24)
> > > > > pts=pack.revolutionSurfaceMeridians([[(pt[0],pt[1]) for pt in poly]
> > for
> > > > > theta in thetas],thetas)
> > > > >
> > > > >
> > > >
> > >
> >
> surf=pack.sweptPolylines2gtsSurface(pts,capStart=True,capEnd=True,threshold=1e-2)
> > > > > ### add surface to the simulation
> > > > > O.bodies.append(pack.gtsSurface2Facets(surf,color=(1,0,0)))
> > > > > #####generate the packing and add it to the simulation
> > > > > sp=SpherePack()
> > > > >
> > > > >
> > > >
> > >
> >
> sp=pack.randomDensePack(pack.inGtsSurface(surf),radius=rS,returnSpherePack=True)
> > > > > sp.toSimulation()
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
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