[Rock-dev] Convention Question: Orientations

[Jakob Schwendner]

On December 10, 2012 at 4:56 PM Matthias Goldhoorn <matthias.goldhoorn at dfki.de>
wrote:
> I'm not sure and couldn't find anything to this in the
> http://rock.opendfki.de/wiki/WikiStart/Standards RG1
>
> Does an Quaternion give the Transformation World2Robot or Robot2World by
> default.
A quaternion does not know anything about robots or worlds... At least in imoby
we always interpret a pose transforms as body to world, as this is the most
intuitive way when setting up the transform, and for some other reasons.

>
> Details:
> If we wrote an component that assumes an RBS-Orientation q as input.
> Our Systems want to calculate an world position 1 meter in the front:
> assume v1(1,0,0)
> Is then q*v1 the "world" relative position or q.inverse()*v1?
>
Lets say you mean that the input to your component is a RigidBodyState which
gives you a body to world transform t (as defined above). If v1 is in body
coordinates, t * v1 will give you the point v1 in world frame, or if you are
just interested in the rotation component q of t, you can of course also do q *
v1.

cheers,

Jakob
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