Can't give you a good clear explanation but I found it in the docs.

Found it under tween and time.

Zitat

Instead of using a fixed time for the change it is possible to define the maximum moving distance for the value and a time for that distance.
This allows to use a short time for a short distance and long time for a long distance. This can be done by using the distance function:

distance(maxdistance,maxtime)
maxdistance - the maximum distance between the start and the destination value
maxtime - the time in seconds for this maximum distance

Hi,

here the link to the documentation:
http://krpano.com/docu/actions/#tween

it's a bit difficult to explain, but here a try:

without distance() the tween will use the given time for changing the variable from the current value to the given one,

but with distance() it's possible to define the distance between a min and max value and the need that would be needed for that distance,

when the current value is now between the distance of the min/max values it would need a shorter time for changing,

I have made a quick example here:
http://krpano.com/krpano.html?xml=docu/a…eendistance.xml

click the both points and after 1-2 seconds click them again,
on each click they will change the direction,

the upper point will need 4 seconds for the whole way from left to right, but when clicked on
the way during moving it will need fewer time (relative to the new distance) for the rest way,

the lower point will need 4 seconds for every move, anytime, even if it is just a few pixels away
from the the destination,

best regards,
Klaus

what is unit of maxdistance value and how can i measure max distance for my 3d project?