velocity==NaN! & fixed=False

> I make a facetbox with dynamic = true (fixed =False), and a error occured: velocity==NaN!> How can I fix this problem.> the mass of the box was already assigned

if you created the box from facets, it cannot have a mass, because
facets are always
non-dynamic bodies.

Without an example script is difficult to say, why you have velocity==NaN!
Anton

On Sun, Dec 4, 2011 at 5:20 PM, Alvin
<email address hidden> wrote:
> New question #180889 on Yade:
> https://answers.launchpad.net/yade/+question/180889
>
>
> Hi, all
> I make a facetbox with dynamic = true (fixed =False), and a error occured: velocity==NaN!
> How can I fix this problem.
> the mass of the box was already assigned
>
> best regards
>
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O.bodies.append(utils.geom.facetBox( center=(5,5,5), extents=(2.0,2.0,2.0) ,fixed=False,wire=False,wallMask=31,material=-1))

and
O.bodies[-1].mass=20000
O.bodies[-2].mass=20000
 ....
 to assign mass to them

and an error occured like " bodies 2230 has a velocity==NaN! " the body 2230 was part of the facetbox

but instead of creating a Box, no such error

> O.bodies[-1]
> O.bodies[-2]

As far as I know, indexes cannot be negative.

idx = O.bodies.append(utils.geom.facetBox( center=(5,5,5),
extents=(2.0,2.0,2.0)
,fixed=False,wire=False,wallMask=31,material=-1))

in this case idx will have indexes of newly created facets.
Anyway, giving a mass to facets will not have an effect.
Facets will not move, for example, from gravity or interactions with
another bodies.

Anton

Thanks Anton
but the faccet can be move by force with the instruction in the Imposing condition of the manual, which write these
"Facets are case in the point: utils.facet makes them non-dynamic by default, as they have zero
volume and zero mass (this can be changed, by passing dynamic=True to utils.facet or setting
Body.dynamic; setting State.mass to a non-zero value must be done as well). The same is true for
utils.wall"

O.bodies[-1] really point to the last particle produced

And I try the above instruction and the facet move, but facets of a box did not interact with each other. So one can't apply some force on a single facet of the facetsbox.