Result channels¶

The result is a CSV file, one row per output time, one column per channel. Channel names are <element>.<output>.

Bodies¶

channel
`R_x`, `R_y`, `R_z`	position of the center of mass [m]
`theta0` … `theta3`	orientation (Euler parameters)
`Rdot_x`, `Rdot_y`, `Rdot_z`	velocity of the center of mass [m/s]
`omega_x`, `omega_y`, `omega_z`	angular velocity, global components [rad/s]
`omega_body_x`, …	angular velocity, body components
`T`	kinetic energy [J]
`H_x`, `H_y`, `H_z`	angular momentum about the center of mass
`theta_norm`	norm of the Euler parameters (1; a check of the integration)
`Rddot_x`, `Rddot_y`, `Rddot_z`	acceleration of the center of mass [m/s²]
`omegadot_x`, … / `omegadot_body_x`, …	angular acceleration, global / body components [rad/s²]

The accelerations are those the solver computes in every step (HHT solves for them), not difference quotients of the velocities: they do not depend on output_step and keep their peaks. For the motion felt at a point (a seat, a sensor, the driver's head) use a sensor.

Joints and drivers¶

One constraint force per fixed direction of the joint frame: hinge.dx.lambda, hinge.dy.lambda, hinge.dz.lambda (forces [N]), hinge.ax.lambda, … (torques [N m]). Drivers: <driver>.lambda, the force or torque that prescribes the motion.

Forces¶

type	channels
`spring_damper`	`length`, `velocity`, `force` (tension positive)
`torsion_spring`	`angle`, `rate`, `torque`
`bushing`	`displacement_x/y/z`, `rotation_x/y/z`, `force_x/y/z`, `torque_x/y/z` (bushing frame)
`force` / `torque`	`force_x/y/z` / `torque_x/y/z` (global)
`expression_force` / `expression_torque`	`value` (the law), `force_x/y/z` / `torque_x/y/z`
`tire`	`force_x/y/z` (contact frame), `slip0`, `slip1`, `friction`, `penetration`, `contact_x/y/z`, `road_height`

Measures are not channels; they enter the forces that use them.

Sensors¶

position_x/y/z (global), velocity_*, acceleration_*, specific_force_*, angular_velocity_*, angular_acceleration_* in the sensor frame. See Sensors.

Reading the results¶

In the viewer: click a channel to plot it; formulas for derived channels.
With the assistant: channels lists them, results gives statistics and a table.
In Python: pandas.read_csv("model.csv"), or fdgen.view.scene.read_results(path) for a dictionary of numpy arrays.