Re: Euler angles

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Alejandro Saez (cano++at++silicon.cl)
Wed, 13 May 1998 13:50:57 -0400


On May 13, 2:55pm, Stefano Conconi wrote:
> Subject: Euler angles
> Hi,
> Could some one tell me somethinghs about the transformation between
>
> Euler parameters - Euler angles- Yaw Pitch and Roll
>
> for the orientation of an object?
>
> Which algorithms I can use to do this transformation?
>
> Or where can I find some usefull links about all of this kind of
> orientation rappresentation?
> --
> -----------------------------------------------------------------
> Ing. Stefano Conconi
> STIGMA On-Line S.r.l.
> PAVIA - Italy
> -----------------------------------------------------------------
> E-Mail: conconi++at++stigma.it Phone: +39 (0382) 578948-9
> WWW: http://www.stigma.it Fax: +39 (0382) 577902
>
>
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>-- End of excerpt from Stefano Conconi

They are the basically same thing, euler angles is just a way of representing
an object's orientation, and they are basically the angles along the principal
axis (x,y and Z), which is the definition of Pitch, yaw and Roll. Now a lot of
confusion usually arises because of the definition of what is positive X,
positive Y and positive Z, and also what is considered to be a positive
rotation (either left or right hand) and also which positive axis is the
"heading". This gives A LOT of different ways of representing the same thing.
For example:

        Classical Flight Simulation:

                +X left
                +Y away from observer
                +Z down
                right hand angles
                +X is "move forward"

        Foley,

                +X left
                +Y up
                +Z from screen towards observer
                right hand angles
                +X is forward

        Performer (not sure, but I think)
                +X left
                +Y from screen towards observer
                +Z up
                right hand rule
                etc,

        This is just to show that although each and every one of this systems
use Yaw, Pitch and Roll (that is Euler angles) you would end up with totally
different rotation matrices for the same, say, Yaw angle, this sometimes leads
to some confusion.

        Hope this helps,

-- 
------------------------------------------------------------------------
Alejandro Saez
Software Engineer
Silicon Chile S.A.
                                        Avda. Andres Bello 2777, Of. 602
E-mail: asaez++at++silicon.cl              	Providencia
Phone:  +56 (2) 203 3371 Ext. 105       Santiago
Fax:    +56 (2) 203 3370                Chile
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