Sean,
Thank you very much. I tried it and got it to work!
Harun
On Mon, Jun 14, 2010 at 10:11 AM, Christopher Sean Morrison
<[email protected]>wrote:
>
> On Jun 9, 2010, at 11:53 AM, Harun Bayraktar wrote:
>
> > Hi,
> >
> > I would like to calculate the center of gravity and moments of
> > inertia of a combination object. The sequence of MGED commands I
> > use are as follows:
> >
> > opendb intersect.g y
> > make hex.s arb8
> > make seg.s tgc
> > attr set hex.s GIFTmater 2
> > attr set seg.s GIFTmater 2
> > comb int.c u seg.s + hex.s
> > gqa -Am -f density_table hex.s
> > I use the density_table file:
> > 0 10.0 dummy0
> > 2 10.0 dummy2
> > 3 10.0 dummy3
> > I get the following when I run the gqa command:
> >
> > bad LOS (0) on /int.c/seg.s
> > bad LOS (0) on /int.c/seg.s
>
> The main problem is that you don't have any regions defined. A
> "region" is our language for a "part" where a given boolean recipe
> goes from being a shape (i.e., template) and turns into something
> solid that occupies space.
>
> The "LOS" error it shows is a "line-of-sight equivalence factor that
> regions define for describing how much material a given region
> represents. For example, a 50% porous metal object might be modeled
> as a simple solid block but then have its LOS set to 50%. Normally,
> this just defaults to 100% equivalence hence my suspicion that you
> either need a region or there is something wrong with the seg.s object.
>
> You manually set GIFTmater attributes, but you shouldn't have needed
> to and you generally don't want to be setting attributes on
> individual primitives (as they are, by definition, just shapes). Try
> creating a region first:
>
> r int.r u int.c
>
> That will set los and GIFTmater on int.r -- you can change the
> material_id (aka GIFTmater) on int.r using the attr set command.
> Then you can run gqa on that int.r region. See if you still get the
> LOS error.
>
> Cheers!
> Sean
>
>
>
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