This option specifies a factor to control the severity of the banking. The best factor is a subjective decision; a good starting point can best be obtained by using the -b option. Animations representing aircraft of different scales will need different factors. If the slightest curve throws the plane into a 90-degree bank, the factor is too large; if it doesn't bank enough, the factor is too small. The size of the best factor varies inversely with the size of the imagined aircraft plane. If a factor of 0 is used, there will be no banking. This would be appropriate for animating a ground vehicle.

This option is used to estimate a good value for the -f option. The parameter is the maximum desired banking angle. Anim_fly then computes the factor necessary to keep the banking below the specified angle. This value is returned instead of anim_fly's usual output.

Suppress vertical loop smoothing. A special case occurs if the aircraft is to perform a vertical loop. Normally, the algorithm likes to keep the aircraft right-side up. This would cause the airplane to do an instantaneous 180-degree roll as it hits the vertical portion of the loop. To counter this, a capability was built in which prevents this sudden roll, allowing the aircraft to go upside-down in a loop situation. This feature can be suppressed with the -r flag.

Specify the ratio of input rows to output rows, which must be an integer. The default, of course, is one. The accuracy of the output depends on having a large number of input lines, which is not usually a problem in animations, which require a large number of frames per second, anyway. If a test animation with a small number of frames per second is being created, the user should still use an input table with a high number of input rows, reducing the frequency of the output with the -p option. For example, if in.table contains 30 rows for each second of the animation, then the command:

anim_fly -f0.001 -p10 < in.table > out.table

would produce an animation table containing 3 rows for each second of the animation.

Specify the minimum step size for the discrete-time differentiation. At any given point on the flight path, the yaw, pitch, and roll are calculated based on a past point, the current point, and a future point. Normally, these are consecutive points from the input table. If the time difference between the points falls below a certain threshold, then non-consecutive points are used to avoid numerical instability. The default time threshold is 0.1 seconds; this can be raised or lowered using the -s option. Try raising the threshold if the output orientations experience random jitter.