Hi Federic, 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 ------------ > DAPNIA/SPP - Bat. 141 - Piece 26B > CEA-SACLAY - 91191 GIF-SUR-YVETTE Cedex - FRANCE > tel: (33) 01 69 08 46 03 fax: (33) 01 69 08 36 49 > Frederic.Machefert@cea.fr > >
This archive was generated by hypermail 2b29 : Tue Jan 04 2000 - 00:43:29 MET