Marquee selection speed

[Roger H. <rog...@mi...>]

I have been investigating why my program is so slow when a user does
a marquee selection. I set up a reasonable test case of 50 to 60 spheres
and pulled out a rectangle around about 80% of the spheres. Quesa
returned about 28000 hits, and my program works through the list asking
for the data on each of the hits in turn. I find that when I ask for 
item N
the routine e3pick_hit_find is chasing up a list to a depth of N. So in 
total
that is N squared over 2 - about 392000000 times that it has to do
"currentHit = currentHit->nextHit;"
I think this might be why this section of my program might be so slow.

Would it be feasible to use an array instead of a chain?

If so, any hints on how to do it would be appreciated.

Roger.