Re: [eigen] Do we need geometry refactoring?

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I forgot to comment on this before...

On Thu, Jul 29, 2010 at 2:45 PM, Benoit Jacob <jacob.benoit.1@xxxxxxxxx> wrote:
>>> Ok, the question is actually whether we want Translation, Quaternion,
>>> etc. behave like Transformations?
>
> Translation and Quaternion are different beasts here.
>
> The reason for Transform to exist is to represent non-linear (i.e.
> affine/projective) transformations.

Isn't it only the projective part that makes the whole thing
non-linear? It that were true, you have like 2/3rd of the cases being
linear ones.

> Translation is indeed a special case of that. But a Quaternion of norm
> 1 represents a rotation which is linear, so there is no reason to
> bother about Transform here; instead we unify Quaternion with other
> rotations in RotationBase and we take care once and for all of the
> interplay of rotations with general Transformations.

I was primarily thinking about adding methods

::matrix() (returns a homogenous matrix)
::linear() (returns a pure matrix)
::translation (same as ::matrix(), read only expression)

We already have toRotationMatrix() and again it was the different
naming that confused me.

- Hauke



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