Determining Whether Pusher Is In Position To Move Marker To Destination

[Joel Witt]

Hello,

This is to inquire about the example method of determining whether the
Pusher is in a position to move a Marker toward the target. The method
applies the dot product of unit_vector_marker_to_target and
unit_vector_pusher_to_marker and says the Pusher is in Position if the
dot product of the unit vectors is under 0.7, which means the Pusher
is somewhere in the pi/2 field on the far side of the Marker bisected
by the vector_marker to target, i.e. :

Target
^
|
|
Marker
/ \
/ pi/2 \
/ \
/ pusher \
/ must be in \
/ this zone \

This post is to inquire as to how the value of pi/2 was determined.
When drawing up a scheme to place the Pusher in a position to move the
Marker I was initially planning to draw a line through the Target and
Marker and move the Pusher onto that line, however this method seems
to be more liberal than what I had made.

Am I missing some logical consequence of the physics of elastic
collisions or was this angular region arrived at empirically.

Joel

[spongman]

i expect it was somewhat arbitrary.

anyone using a genetic algorithm to optimize these kinds of
parameters?