yade-dev team mailing list archive

[Anton Gladky <gladky.anton@xxxxxxxxx>]

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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