From: Andrew Dalke (
Date: Thu Sep 04 2003 - 18:57:00 CDT

Ioana Cozmuta wrote:
> What is the best way to select all the particles that are inside a
> channel
> of variable diameters at various positions along the channel axis?
> Any good suggestion?

Do you have the equation for the line?

Suppose it's along the z axis, then you can do

(x*x + y*y) < 5*5

which is all atoms within 5 A of the z axis. The
extrapolation to an arbitrary line is just a bit of math.