Re: [eigen] Eigen and rigid body simulation

[Christian Mayer <mail@xxxxxxxxxxxxxxxxx>]

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Mathieu Gautier schrieb:
> Hi,
> 
> I plan to use eigen in one of our library to simulate rigid body in 3D.
> I have several basic elements (Wrench, Twist, Displacement, etc.) based
> on Eigen matrix and quaternion which are used to manipulate the rigid
> bodies velocities, forces, positions, etc. I think that this elements
> could be added to Eigen as a new module, although, they are quite tied
> to the geometry module. So, if you are interested I can submit a patch.

Hi Mathieu,

this sounds like a sensible way coming from the Eigen background (i.e.
geometry).

But when you are talking about linear or angular "mechanics" you should
also think about its analog applications: thermodynamics and electricity:

force = torque = current = heat transport
velocity = angular velocity = potential = temperature
mass = inertia = capacity

The formulas to handle those quantities are exactly the same.

I.e. although most quantites are only 1D (and not 3D like linear and
angular motion) this is really asking for a generic mechanism to handle
it. And - so far Eigen could only spend it's expression templates - it
might be a good usecase for the solving methods of Eigen.

But in either case (only mechanics or generalized) I think it's out of
the scope of Eigen. It's a good usecase though.

CU,
Chris

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