The TRotMatrix constructor wit six angles uses the GEANT convention:
theta1 is the polar angle of the x-prim axis inthe main reference system
(MRS), theta2 and theta3 have the same meaning for the y-prim and z-prim
axis.
Phi1 is the azimuthal angle of the x-prim in the MRS and phi2 and phi3
have the same meaning for y-prim and z-prim.
for example, the unit matrix is defined in the following way.
x-prim || x, y-prim || y, z-prim || z
means: theta1=90, theta2=90, theta3=0, phi1=0, phi2=90, phi3=0
You can find all the details in the GEANT manual.
Regards, Marek
On Wed, 10 Feb 1999, Frederic MACHEFERT wrote:
> Hi,
>
> I use 3d objects with Root. The rotation matrix for a 3D object doesn't
> seem to be defined by three angles but its calculation involves six angles
> called theta1, theta2, theta3, psi1, psi2, psi3. What is the meaning
> of these angles ?
>
> Thank you in advance.
> Frederic.
>
>
> -------- Frederic Machefert ------------
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> Frederic.Machefert@cea.fr
>
>