Re: [eigen] Eigen and rigid body simulation

[Benoit Jacob <jacob.benoit.1@xxxxxxxxx>]

2009/11/27 Mathieu Gautier <mathieu.gautier@xxxxxx>:
>> If I understand correctly, Displacement is a specialization of the
>> existing Transform class for the isometry in 3D case (just like Rohit's dual
>> quaternion implementation), so maybe Transform3D or similar would be easier
>> to relate with the more general implementation.
>
> Yes, the name is not ideal.
>
>> If you are indeed familiar with KDL, and you found out that it does not
>> adapt well to your needs, I'd be very interested in knowing what
>> shortcomings you found for your application domain, and how would you
>> address them otherwise.
>
> Yes, I know about KDL. My main concern is that we choose to use Eigen for a
> big part of our code, but we have also many old libraries with their own
> mathematical libraries (C style libraries). So I'd like to use the Map<...>
> mecanism to interface our new libraries with the old one this mecanism is
> not in KDL, since its basics elements (rotation, frame, twist, wrench) are
> not based on Eigen. That's the main reason for not using KDL frame,
> rotation, etc.

Adolfo:

Interesting. I would naively assume that the biggest benefit that KDL
draws from not exposing the Eigen objects in the API is to have an API
that's independent of Eigen's API? Not a bad decision as it'll allow
you to move seamlessly to Eigen 3.0. But perhaps after Eigen 3.0 it
would be OK for you to expose Eigen in the API?

Mathieu:

If that happened, would you still want to have this stuff in Eigen or
would your rather use KDL for that? Since you were able to reformulate
above everything in terms of Lie algebra and without any mechanics, it
seems like this is now really interesting to have in Eigen,
independently of the particular use case you had in mind, but I also
don't want to do it if its main author (you) is going to not use it in
the future because KDL does it!

Benoit