[ODE] Moment of Inertia

[Brian Clarkson]

Martin

Unfortunately I'm not that Brian Clarkson. I'm just a very ordinary Brian
Clarkson.

One more question:
Do I use the xyx MOIs calculated by the formula or do they need further
conversion.

Many thanks.

Brian..





-----Original Message-----
From: Martin C. Martin [mailto:martin at metahuman.org]
Sent: 20 December 2003 11:49
To: Brian Clarkson
Cc: ode at q12.org
Subject: Re: [ODE] Moment of Inertia


Hey Brian,

The MOI tensor is just a matrix, and if you choose the axes as the
"natural" axes, it's a triangular matrix.  So, just put the x/y/z MOIs
along the diagonal, and make the rest of the entries zero.  Take a look
at the dSetMassX functions (or is it dMassSetX?  Something like that.)

By the way, is this the Brian Clarkson who did his Ph.D. with Sandy
Pentland?  'Cause I'm now a postdoc with Sandy...

Cheers,
Martin

Brian Clarkson wrote:

> Can any of you MOI experts help me with this.
>
> Its not difficult to determine the x/y/z MOIs of a body if you are able to
> handle
> it. For example a small model car.
> See http://kwon3d.com/theory/moi/meas.html  [22].
>
> Its not difficult to suspend a body to form a pendulum and measure all the
> values needed for the calculation.
> Its also not difficult to create a hinge and replicate the setup with ode
to
> verify results. What I don't know
> is how to create to the MOI tensor for the known xyz MOIs. Can anyone help
> me.
>
> Brian..
>
>
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