yade-dev team mailing list archive

[Klaus Thoeni <klaus.thoeni@xxxxxxxxx>]

Hi Anton,

thanks for your suggestion. Actually I had already a look at the "groupMask" 
option. It works fine if you have groups of particle which should interact or 
not, as you explain in your example. However, in my case I have three groups 
of particle and I want avoid contact detection between the particles of one 
group, the mesh.

So basically I want avoid new contact detection of particles belonging to one 
group, or better contact between WireMat particles. 

I think one option could be to put all particles of this group on different 
groupMasks. But I have 1000s of particles in this group.

Any other ideas?

Thanks, Klaus
 

On Wed, 11 Jan 2012 05:47:30 PM Anton Gladky wrote:
> Hi Klaus,
> 
> one of  possible solutions is to use "groupMask', which is bitmask.
> For example, you have 3 groups of particles. 1 and 2, 2 and 3 should
> interact, otherwise
> 1 and 3 should not. In this case bitmask can be so written:
> 
>     16 8 4 2 1
> 1) 1   0 0 1 0    =  17
> 2) 0   1 0 1 1    =  11
> 3) 0   0 1 0 1    =  5
> 
> When interaction is detected, the collider (I guess) uses bitwise
> AND-operation for bitmasks of 2 interacting particles.
> And if the sum is more than 0, then interaction is created, otherwise
> not. So, if you see an example, the group 1 and 2, 2 and 3
> will give the sum 1 and interaction will be created, 1 and 3 gives 0,
> so particles will not interact.
> 
> Hope that helps.
> Anton
> 
> On Wed, Jan 11, 2012 at 6:45 AM, Klaus Thoeni <klaus.thoeni@xxxxxxxxx> 
wrote:
> > Hi guys,
> > 
> > I have a tricky question. How can I avoid new contact detection between a
> > group of particles?
> > 
> > For my WireMP a first create particles which represent the net. Second, I
> > create a link between particle since particle interact remotely (there is
> > no physical contact between these particles). However, once the link is
> > created I want to avoid new contact detection between those particles. I
> > still need contact detection between the net and some other particles
> > (e.g. rock block).
> > 
> > Any idea how to implement this? I think it must be done somewhere in the
> > collider, or not?
> > 
> > Thanks,
> > 
> > Klaus
> > 
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