portion of stdout from rztog4 executable, SVT rz file as input:

Use of Safety to reduce geometry interrogation

Addition of Low Order Steppers (W.Wand)

• 1st/2nd order for fields that are interpolated

Ability to select Field for each volume

Fast advancement in smooth fields

• multiple turns in an integration step

Approximate the path

• Building chords
• Maximum distance curve-chord < dchord
• Interrogate geometry with chords

dchord=”miss distance”

• user defined

Intersection precision

Currently available steppers are Runge-Kutta integrators

• 4th order Classical RK or
• 4th/5th order Cash-Karp improved RK
• Nystrom (fewer field evaluations) .

Soon we will have lower order integrators

• for interpolated fields typical of detectors.

Create Concrete Field & Driving Force classes

Choose a Stepper that can

• advance the set of ODE of motion &
• calculate an error estimate for endpoint

Use the Integration Driver to obtain

• an endpoint good to a given accuracy

Design of Field class category

• Field and EquationRHS abstract classes
• Integration of motion: driver & stepper
• Chord Finder

First implementation of all classes

• Field Propagator (in Geometry]
• Integration driver and steppers

Integration into transportation

Solution of the Equations of Motion

• Given a Field and a derived Driving Force

Intersection an approximate path with the Model Detector Geometry

• the curved path is split into linear sections

Volume description and Navigator are intertwined

Navigator’s performance is steady

• retaining its edge over Geant-3 in tests

Touchables

• pack full volume location information
• are used in tracking