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[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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