I have created a toy tracker with TGeometry to study the errors on d0 and z0 measurements. I initially tested it with straight tracks initialized by geom->InitTrack(0,0,0,nx,ny,nz) where the initial directions are given by a random number generator. I have just implemented a uniform B-field and now want to have tracks seeded by a TParticle with a given charge and momentum so that my tracks will now become curved (helictical) tracks. I am not certain how to connect my track initialization to a single instance of a TParticle. Can you please help me understand this step?